FORAGING ECOLOGY OF THE VERVET MONKEY (CHLOROCEBUS
AETHIOPS) IN MIXED LOWVELD BUSHVELD AND SOUR LOWVELD
BUSHVELD OF THE BLYDEBERG CONSERVANCY, NORTHERN PROVINCE,
SOUTH AFRICA.
by
ALAN SEAN BARRETT
Submitted in partial fulfillment of the requirements for the degree
MAGISTER TECHNOLOGAE
Nature Conservation
Applied Behavioural Ecology & Ecosystem Research Unit
College for Agricultural & Environmental Sciences
University of South Africa
Pretoria
October 2005
Supervisors: Prof. S.P. HENZI (University of Central Lancashire)
Prof. L.R. BROWN (University of South Africa)
Dr. L. BARRETT (University of Liverpool)
LIST OF CONTENTS
i
LIST OF CONTENTS
LIST OF FIGURES
iii
LIST OF TABLES
vii
LIST OF APPENDICES
viii
ACKNOWLEDGEMENTS
ix
PREFACE
x
References
xi
INTRODUCTION
1
1.1
Prolegomenon
1
1.2
Research hypothesis under investigation
4
1.3
Aim and objectives
4
1.4
Dissertation exposition
5
1.5
Contents of dissertation
6
CHAPTER 1:
References
7
LITERATURE REVIEW
11
2.1
Vervet evolution and taxonomy
11
2.2
Vervet distribution
12
2.3
Previous studies on vervets
13
CHAPTER 2:
References
17
STUDY SITE
24
3.1
Location, size and topography
24
3.2
Geology
27
3.3
Land types
29
CHAPTER 3:
i
3.4
Climate
34
3.5
Flora
38
3.6
Fauna
39
References
41
METHODS
43
4.1
Vegetation mapping and habitat description
43
4.2
Vervet monitoring
46
4.3
Census
47
CHAPTER 4:
References
56
59
CHAPTER 5:
VEGETATION ANALYSIS
CHAPTER 6:
HABITAT UTILISATION AND FOOD SELECTION
107
CHAPTER 7:
ACTIVITY BUDGET
153
CHAPTER 8:
GENERAL DISCUSSION AND CONSERVATION ISSUES
184
191
REFERENCES
ii
LIST OF FIGURES
Ch2 Figure 1:
Known distribution of vervets in Africa (Kingdon, 1997;
12
Skinner & Smithers, 1990).
Ch3 Figure 2:
Location of the study area within the Northern province of
South Africa.
24
The study area is demarcated with a
rectangle.
Ch3 Figure 3:
A GPS generated vector map of roads and infrastructure in
26
Blydeberg Conservancy depicting the study area within the
confines of the yellow rectangle and GPS mapped roads
overlaid onto a digitized aerial photo of Blydeberg
Conservancy.
Ch3 Figure 4:
Geological map of the study area (demarcated by the
28
yellow rectangle) and surrounds as adapted from the 1:250
000 Geological Series 2430 Pilgrims Rest (South Africa,
1986).
Ch3 Figure 5:
Terrain form sketch indicating the various land types of the
33
study area. a) is land type Fa, b) is land type Fb, c) is land
type Ib, and d) is land type Ic.
Ch3 Figure 6:
Average monthly rainfall and temperatures for Blydeberg
36
Conservancy and Hoedspruit from 05/1999 to 04/2004.
Ch3 Figure 7:
Rainfall and temperature summary for the study period 01
37
May 2003 to 30 April 2004 for the study area.
Ch4 Figure 8:
Census transects walked – all transects were walked from
50
east to west i.e. a1 to a2, b1 to b2, c1 to c2 etc. to prevent
glare from the sun distorting visibility. Census transects
are depicted in green with roads in red.
Ch5 Figure 1:
Location of Blydeberg Conservancy within the Northern
Province of South Africa.
iii
62
Ch5 Figure 2:
Terrain form sketch indicating the various land types of the
64
study area. a) is land type Fa, b) is land type Fb, c) is land
type Ib, and d) is land type Ic.
Ch5 Figure 3:
Average monthly rainfall and temperatures for the
67
Blydeberg Conservancy and Hoedspruit from 05/1999 to
04/2004.
Ch5 Figure 4:
Vegetation map of the study area within the Blydeberg
71
Conservancy. Map depicts the various plant communities,
sub-communities and variants.
Ch5 Figure 5:
Community ordination scatter diagrams depicting a) tree
93
cover, shrub cover, herb cover, and grass cover with trend
lines
portraying
tendencies
in
the
aforementioned
parameters from community 1 to community 4; and b)
slope, erosion and rockiness with trend lines depicting
inclinations of aforementioned parameters from community
1 to community 4.
Ch6 Figure 1:
A map of the study area within the Northern Province of
112
South Africa.
Ch6 Figure 2:
Rainfall and temperature summary for the study period.
113
Ch6 Figure 3:
Vegetation map of the study area depicting various
119
communities, sub-communities and variants.
Ch6 Figure 4:
Community utilisation. Community utilisation for wet and
121
dry seasons is depicted, with community size reflected for
comparison.
Ch6 Figure 5:
Daily distances travelled and area covered by the study
troop during the study period. a) Represents movement
patterns for the period including May 2003 to October 2003
and May 2004 (dry season).
b) Represents movement
patterns for the period including April 2003 and November
2003 to April 2004 (wet season).
iv
123
Ch6 Figure 6:
Study troop home range during the study period. Area was
124
calculated in ha using the area within the bounding
polygon. a) Is combined study troop wet and dry ranges –
blue arcs are wet season daily ranges and red arcs are dry
season daily ranges. b) Is bounding polygon for combined
wet and dry ranges. Numbered circles depict neighbouring
troop locations and sizes as observed during census
transects walked.
Ch6 Figure 7:
Seasonal foraging.
The graph depicts the number of
125
observations for various food sources selected for both dry
and wet seasons.
Ch6 Figure 8:
Five most commonly utilized plant species for a) the wet
127
and b) the dry seasons. Pie charts show preferred plant
species by season. There were some species that were
consumed across seasons as they started fruiting during
the wet season and continued into the dry season.
Ch6 Figure 9:
Cumulative Percentage Species Contribution of various
128
plant species foraged on.
Ch6 Figure 10: Main forage plant species electivity index.
Utilisation of
130
main forage species in relation to the availability of such
expressed as an electivity/selectivity index for the wet
season, dry season and combined for both seasons.
Ch6 Figure 11: Plant community electivity index.
Utilisation of plant
131
communities in relation to their availability expressed as an
electivity/selectivity index for the wet season, dry season
and combined for both seasons.
Ch7 Figure 1:
Location of the Blydeberg Conservancy within the Northern
159
Province of South Africa.
Ch7 Figure 2:
Rainfall and temperature summary for the study period.
160
Ch7 Figure 3:
Percentage of total time allocated to various activities.
163
v
Ch7 Figure 4:
Seasonal activity breakdown.
164
Ch7 Figure 5:
Activity breakdown by sex.
165
Ch7 Figure 6:
Diurnal comparison of activities across seasons.
168
vi
LIST OF TABLES
Ch3 Table 1:
Rainfall for the last five years with a breakdown for the study
38
period.
Ch4 Table 2:
Modified Braun-Blanquet cover abundance scale (Mueller-
45
Dombois & Ellenberg, 1974).
Ch4 Table 3:
Census transects for Blydeberg with starting co-ordinates,
53
ending co-ordinates and length of transects.
Ch4 Table 4:
Census data reflecting species occurring on Blydeberg
54
Conservancy.
Ch5 Table 1:
Phytosociological table of the vegetation for the study area
72
within the Blydeberg Conservancy.
Ch5 Table 2:
Table of less prevalent plant species occurring at Blydeberg
77
and not represented in Table 1.
Ch6 Table 1:
Communities utilized seasonally by the study troop.
120
Ch6 Table 2:
Seasonal average distances travelled and average area
122
covered monthly for the study period.
Ch6 Table 3:
Vervet food selection for the study period. Table reflects
126
diet item, Chi square test results and significance of diet
items with regards to wet season. Exceptions are marked
and discussed.
Ch6 Table 4:
Breakdown of various plant part percentages contributing
129
towards the study troops diet for the wet and dry seasons.
Ch7 Table 1:
Percentage of time allocated to various activities for different
vervet activity related studies.
vii
173
LIST OF APPENDICES
Appendix 1:
Checklist of all plant species recorded during this study for
the Blydeberg Conservancy and the study area.
viii
214
ACKNOWLEDGEMENTS
I would like to express my sincere gratitude and appreciation to:
•
Prof. D. Mitchell for the kind use of his property and facilities for my
research.
•
Prof. S.P. Henzi and his wife Dr. L. Barrett for their continued assistance,
guidance and mentorship throughout this project, especially with regards to
statistical data processing, software and primate behaviour.
•
Prof. L.R. Brown for his continued assistance, guidance and mentorship
throughout this project, especially for sharing his botanical insight with me
and assisting me with the processing of my vegetation data.
•
The NRF for funding my research through their bursary scheme.
ix
PREFACE
Vervet Monkeys (Chlorocebus aethiops) are versatile primates of the suborder
HAPLORHINI, family CERCOPITHECIDAE, subfamily CERCOPITHECINAE, and
genus Chlorocebus (Skinner & Smithers, 1990). They are a widely distributed
species that adapt easily to a variety of environments, occurring throughout the
Northern and Southern Savanna, from Senegal to Sudan and south to the tip of
Southern Africa (Estes, 1992).
According
to
Estes
(1992),
vervets
are
opportunistic
omnivores,
being
predominantly vegetarians that live on wild fruits, flowers, leaves, buds, seeds,
pods, sap, roots and tubers. Occasionally they will feed on invertebrates (grubs,
termites, grasshoppers) and vertebrates (bird and reptile eggs and chicks) (Skinner
& Smithers, 1990).
Not much ecological research has been done on vervets outside the tropics to
date, and it was thus considered necessary to determine how vervets cope with the
effects of temperate area seasonality.
The aim of this study was to describe the habitat structure of a vervet monkey
troop’s territory and then to investigate the effects of seasonality on differences in
their diet (both overall and with respect to sex differences), activity patterns and
habitat utilisation.
x
REFERENCES
ESTES, R.D.
1992.
Behaviour Guide to African Mammals.
Los Angeles:
University of California Press.
SKINNER, J.D. & SMITHERS, R.H.N.
African Sub region.
1990.
2nd ed.
The Mammals of the Southern
South Africa: University of Pretoria.
xi
CHAPTER 1
INTRODUCTION
1.1 Prolegomenon
Vervet monkeys (Chlorocebus aethiops) are highly successful African primates
occupying a wide variety of habitats.
Due to their inherent ability to adapt to
various, often harsh environments they occur widespread throughout Africa and
are present in areas ranging from semi desert to gallery forest. Being omnivorous
they are capable of finding food in even the poorest of environments (Skinner &
Smithers, 1990; Estes, 1992; Kingdon, 1997; Isbell et al., 1998; Dunbar & Barrett,
2000). As a species they are second only to baboons in their ability to survive
across a diverse range of ecological conditions. They appear to cope well in most
habitats, having filled various niches in what often appears to be extreme
surroundings.
In southern Africa, vervets have successfully adapted to living away from forests
and occupy the African savanna. They are not as adept at utilizing their habitats
as baboons are, being restricted mostly to areas in close proximity to water and
trees; whereas baboons maximize the use of their environments, being labeled the
most successful African primates (Dunbar & Barrett, 2000).
Being a highly adaptable and intelligent species, vervets have become a pest to
humans, and are renowned for raiding crops, orchards and even human dwellings
(Lee et al., 1986; Saj, 1999). According to Estes (1992), vervets rank second only
to baboons as agricultural pests and are often found in the same areas as
baboons, adding to the destruction in these areas.
1
Due to their perceived destructive natures, vervets frequently raise management
issues in both protected and non-protected areas, particularly where commercial
enterprises and protected areas are adjacent to one another. It is envisaged that
by understanding their dietary requirements and seasonal movement patterns that
a set of preliminary management proposals for minimizing damage to human
interests could be drafted.
South Africa has a temperate sub-tropical climate with considerable regional
variations caused by differences in elevation, wind systems, and ocean currents.
Seasonality affects all animal species living in such temperate sub-tropical
environments. Changes in temperature and day length that accompany changes
in season are markedly different at different latitudes. Such changes influence the
activity patterns of various animal species.
Many migratory bird and mammal
species are affected by seasonality, with fluctuations in day length and temperature
often being the precursor to their migratory behaviour (Maclean, 1990; Alcock,
1993; Krebs & Davies, 1999). The life cycles of most insects, a source of food for
vervets, are also seasonally driven (Skaife et al., 1979; Scholtz & Holm, 1989).
Primates often share habitats with other animals and are similarly affected by
seasonality. Seasonal variations in day length therefore have a strong behavioural
affect on their activity patterns (Barton et al., 1992; Bronikowski & Altman, 1996;
Hill et al., 2003; Hill et al., 2004; Marais 2004). At Blydeberg the vervets share
their habitats with baboons and though both species are similarly affected by
seasonality, their respective reactions vary with the baboons spending more time in
open grassland areas and the vervets remaining in or adjacent to areas of gallery
forest.
Vegetation growth and production in Southern Africa is also seasonally dependant,
with certain phases of a plants life cycle being sensitive to changes in day length
and temperature fluctuations.
2
Examples of distinctive life cycle phases sensitive to seasonality in plants include
rate of germination, rate in amount of die off and/or survival, biomass production,
intensity and time of flowering and fruiting with accompanying yields, and overall
reproductive capacity (Barbour et al., 1987; Cowling et al., 1997; Kent & Coker,
1997). Rainfall, especially in South Africa, is another important factor affecting
plant growth.
For any research on ecologically related issues of animals to be relevant, it is of
utmost importance to first obtain an understanding of their habitat.
Once the
structure of their habitat is understood, it becomes easier to analyse their
associated behaviour.
Historically, several large scale vegetation research
projects have been done on the vegetation of Southern Africa (Acocks, 1988;
Bredenkamp & Bezuidenhout, 1995; Cowling et al., 1997; Van Oudtshoorn, 1999),
with very little having been done on a micro-scale. However, currently the impetus
of a lot of current vegetation and ecological research is on obtaining data of a more
detailed and specific nature (Bredenkamp et al., 1989; Mathews, 1991; Brown &
Bredenkamp, 1994; Mathews et al., 1994; Bezuidenhout, 1993, 1996; Brown,
1997). There is no recorded vegetation analysis for the study area apart from a
few descriptive studies having been undertaken in the surrounding area (Van der
Schijff, 1963; Van der Schijff & Schoonraad, 1971).
Most studies on vervet foraging ecology have been done in equatorial Africa. Very
little, if anything at all has been done in more temperate zones where seasonal
climatic fluctuations and thus seasonal variations in food type and abundance are
the order of the day. Wherever vervets and humans live in close proximity to one
another, vervets are considered pests as their opportunistic natures cause them to
take advantage of any opportunities for free meals.
Often the important role
vervets play in the ecology of areas they inhabit is not appreciated or understood
as their negative stigma outweighs their benefits to such areas.
3
When land owners in the Blydeberg Conservancy experienced problems with
vervets, such was seen as a unique opportunity to study a troop of semi-habituated
vervets in their natural surroundings. Currently there is no available information on
vervet foraging ecology in mixed and sour lowveld bushveld, or on vervet
management in Southern Africa, and there are no management plans at
Blydeberg.
The problems vervets are envisaged to cause and problems
experienced are not unique to Blydeberg but are widespread throughout their
range. This study aims to provide some insight into vervet foraging ecology, whilst
giving guidelines for a more comprehensive management plan for vervets to
ensure their continued existence.
1.2 Research hypotheses under investigation
It was predicted that the study troop would:
• Utilize more of their home range during the dry season than during the wet
season, thus increasing area used.
• Travel further during the dry season than during the wet season.
• Consume a larger variety of food species during the wet season than during
the dry season.
1.3 Aims and objectives
The overall aims of this study were to provide an insight into the impacts of
temperate area seasonality on the habitat utilisation, food selection and activity
patterns of a vervet troop living in a temperate sub-tropical environment. Another
intention of this study was to provide a set of basic management recommendations
for vervet monkeys in general.
4
Specific objectives for this study were to:
•
Identify, describe, classify and ecologically interpret the vegetation of the study
area within the Blydeberg Conservancy on a floristic basis using Braun-
•
Blanquet methodology.
Compile a set of basic maps for the study area which could be used for the
management of the area i.e. an infrastructure and roads map, a vegetation
•
map, and a seasonal vervet habitat utilisation map.
•
and monitored for data collection purposes.
Locate and sufficiently habituate a vervet troop so that they could be followed
Follow a troop of vervet monkeys over a twelve month period in order to record
their seasonal habitat utilisation, foraging behaviour, food selection, movement
patterns, and activity patterns.
1.4 Dissertation exposition
This dissertation consists of a research article [Chapter 5 - A vegetation
classification and description as a precursor for vervet monkey (Chlorocebus
aethiops) habitat utilisation, food selection and activity analysis in the Blydeberg
Conservancy, Northern Province.] which has been submitted for publication in
KOEDOE, as well as topics/aspects that are presented in the form of unpublished
data chapters, some of which are to be published in other journals at a later stage.
Chapter 5 follows the format required by KOEDOE, whilst unpublished data
chapters follow the format required by the respective journals they are to be
published in. Consequently, some stylistic irregularities and repetitiveness occurs
between the various data chapters, with each chapter forming an entity within itself.
5
A description of the methods used, study area, and a complete literature reference
list are given in each data chapter. Annexures referred to in certain chapters are
supplied at the end of the dissertation. Figures and Tables referred to within data
chapters are applicable only to the specific chapters they occur in and are
numbered consecutively within each respective chapter.
Tables too large to fit onto one page are included as fold-outs attached to the end
of the dissertation. Subsections within all data chapters are unnumbered. All page
numbering in this dissertation are consecutive for each page containing text, tables
or figures, hence the published and unpublished articles pages have been
renumbered accordingly.
1.5 Contents of dissertation
This dissertation contains detailed information on the phytosociology of the study
area within the Blydeberg Conservancy, followed by information on the study
troops seasonal habitat utilisation, foraging behaviour, movement patterns, food
selection and activity patterns.
A complete species list of all plant species identified during plant surveys is
provided as an Annexure at the end of the dissertation. A comprehensive list of all
references cited in all chapters is also included.
6
REFERENCES
ACOCKS, J.P.H. 1988. Veld types of South Africa.
3rd ed. Mem. Bot. Surv. S.
Afr. 40, Government Printer, Pretoria.
ALCOCK, J.
1993.
Animal Behaviour.
5th ed.
Massachusetts: Sinauer
Associates, Inc.
BARBOUR, M.G., BURK, J.H. & PITTS, W.D. 1987. Terrestrial Plant Ecology. 2nd
ed. Massachusetts: The Benjamin/Cummings Publishing Company, Inc.
BARTON, R.A., WHITEN, A., STRUM, S.C., BYRNE, R.W. & SIMPSON, A.J.
1992. Habitat use and resource availability in baboons. Animal Behaviour,
43: 831-844.
BEZUIDENHOUT, H. 1993. Syntaxonomy and synecology of Western Transvaal
Grasslands. Ph.D. dissertation, University of Pretoria, Pretoria.
BEZUIDENHOUT, H. 1996. The major vegetation communities of the Augrabies
Falls National Park, northern Cape. 1. The southern section. Koedoe, 39: 724.
BREDENKAMP, G.J. & BEZUIDENHOUT, H. 1995. A proposed procedure for the
analysis of large data sets in the classification of South African Grasslands.
Koedoe, 38(1): 33-39.
BREDENKAMP, G.J., JOUBERT A.F. & BEZUIDENHOUT, H.
1989.
A
reconnaissance survey of the vegetation of the plains in the PotchefstroomFochville-Parys Area. South African Journal of Botany, 55: 199-206.
7
BRONIKOWSKI, A.M. & ALTMANN, J. 1996. Foraging in a variable environment:
weather patterns and the behavioural ecology of baboons. Behav. Ecol.
Sociobiol, 39: 11-25.
BROWN, L.R.
1997.
A plant ecological and wildlife management plan of the
Borakalalo Nature Reserve, North-west Province.
Ph.D.
dissertation.
University of Pretoria, Pretoria.
BROWN, L.R. & BREDENKAMP, G.J. 1994. The phytosociology of the southern
section of the Borakalalo Nature Reserve, South Africa. Koedoe, 37: 59-72.
COWLING, R.M., RICHARDSON, D.M. & PIERCE, S.M. (ed.). 1997. Vegetation
of Southern Africa. Cambridge: Cambridge University Press.
DUNBAR, R. & BARRETT, L. 2000. Cousins Our Primate Relatives. London:
BBC Worldwide Ltd.
ESTES, R.D.
1992.
Behaviour Guide to African Mammals.
Los Angeles:
University of California Press.
HILL, R.A., BARRETT, L., GAYNOR, D., WEINGRILL, T., DIXON, P., PAYNE, H.
& HENZI, S.P. 2003. Day length, latitude and behavioural (in)flexibility in
baboons (Papio cynocephalus ursinus). Behav. Ecol. Sociobiol, 53: 278-286.
HILL, R.A., WEINGRILL, T., BARRETT, L. & HENZI, S.P.
2004.
Indices of
environmental temperatures for primates in open habitats. Primates, 45: 7–
13.
8
ISBELL, L.A., PRUETZ, J.D. & YOUNG, T.P.
1998.
Movements of vervets
(Cercopithecus aethiops) and patas monkeys (Erythrocebus patas) as
estimators of food resource size, density and distribution.
Behav.
Ecol.
Sociobiol, 42: 123-133.
KENT, M. & COKER, P. 1997. Vegetation Description and Ananlysis – A Practical
Approach. New York: John Wiley & Sons.
KINGDON, J. 1997. The Kingdon field guide to African Mammals. Academic
Press, New York: Natural World.
KREBS, J.R. & DAVIES, N.B. 1999. An Introduction to Behavioural Ecology. 3rd
ed. London: Blackwell Science Ltd.
LEE, P.C., BRENAN, J.P., ELSE, J.G. & ALTMAN, J.
1986.
Ecology and
behaviour of vervet monkeys in a tourist lodge habitat. In: Else J.G., Lee P.C.
(Eds). Primate ecology and conservation. Selected Proceedings of the 10th
Congress Int. Primatological Society, Nairobi, Kenya (July 1984). Cambridge
University Press, Cambridge, U.K: chap. V.3, 229-236.
MACLEAN, G.L. 1990. Ornithology for Africa. Pietermaritzburg: University of
Natal Press.
MARAIS, A.J.
2004.
Resource utilisation of the chacma baboon in different
vegetation types in north-eastern mountain sour veld, Blyde Canyon Nature
Reserve. Mtech. dissertation. University of South Africa, Pretoria.
MATTHEWS, W.S. 1991. Phytosociology of the North-eastern Mountain sourveld.
Msc. Thesis, University of Pretoria, Pretoria.
9
MATTHEWS, W.S., BREDENKAMP, G.J. & VAN ROOYEN, N.
1994. The
phytosociology and syntaxonomy of relative low-altitude areas in the Northeastern Mountain Sourveld, in the eastern Transvaal escarpment region.
Koedoe, 37(2).
SAJ, T., SICOTTE, P. & PATERSON, J.D.
1999.
Influence of human food
consumption on the time budget of vervets. Int. J. Primatology, 20: 977-994.
SCHOLTZ, C.H. & HOLM, E. (ed.). 1989. Insects of Southern Africa. Durban:
Butterworths.
SKAIFE, S.H., LEDGER, J. & BANNISTER, A. 1979. African Insect Life. 2nd ed.
Cape Town: Struik Publishers.
SKINNER, J.D. & SMITHERS, R.H.N.
1990.
The Mammals of the Southern
African Subregion. 2nd ed. South Africa: University of Pretoria.
VAN DER SCHIJFF, H.P. 1963. A preliminary account of the vegetation of the
Mariepskop Complex. Transvaal Provincial Administration. Fauna and Flora,
14: 42-53.
VAN DER SCHIJFF, H.P. & SCHOONRAAD, E.
1971.
The flora of the
Mariepskop Complex. Bothalia, 10, 3: 461-500.
VAN OUDTSHOORN, F. 1999. Guide to grasses of southern Africa. Pretoria:
Briza Publications.
10
CHAPTER 2
LITERATURE REVIEW
2.1 Vervet evolution and taxonomy
According to Dunbar & Barrett (2000) primates are one of the most ancient
mammal lineages currently alive. Their origins date back to the dinosaur age, over
65 million years ago. Fossil evidence suggests first anthropoids (group to which
monkeys and apes belong) appeared around 30 to 35 million years ago (Dunbar &
Barrett, 2000). As climate changes occurred around 12 million years ago, a new
fruit- and seed-eating monkey lineage emerged – the cercopithenes, including
baboons, macaques, guenons and their relatives (Dunbar & Barrett, 2000).
Vervets are guenons “any slender agile Old World monkey of the genus
Cercopithecus, inhabiting wooded regions of Africa and having long hind limbs and
tail with long hair surrounding the face” - Collins English Dictionary & Thesaurus,
1992. Like all other primates, vervets have an evolutionary history of being a
tropical species dependant on forests and their rich supply of food types for
survival.
Vervets successfully invaded the woodland and savanna habitats of Africa from
their ancestral forest homes (Dunbar & Barrett, 2000), but not totally since they
tend to be restricted to riparian and swamp areas.
According to Dunbar & Barrett (2000), vervets are no longer part of the genus
Cercopithecus but have been deemed sufficiently different to be placed in their
own genus Chlorocebus, in accordance with Wilson & Reeder (1993).
11
Vervets have been involved in several taxonomic debates, which have split them
into as many as four species (including pygerythrus, sabaeus, tantalus and
djiamdjiamensis) and twenty one subspecies (Wilson & Reeder, 1993).
Vervets are also referred to as the green or grivet monkey and are currently
taxonomically classified as Chlorocebus aethiops (Dunbar & Barrett, 2000).
2.2 Vervet distribution
Vervets have a wide distribution in Africa, occurring from Senegal to Ethiopia and
southwards to South Africa, as well as on the Islands of Zanzibar, Pemba and
Mafia (Wilson & Reeder, 1993). Figure 1 is a revised map of vervet distribution in
Africa, the map as far as possible matches existing river networks (Kingdon, 1997).
Figure 1:
Known distribution of vervets in Africa (Kingdon, 1997; Skinner &
Smithers, 1990).
12
As previously mentioned vervets inhabit a wide range of wooded habitat types
outside the equatorial rainforest and occur in savanna, woodlands, forest/grassland
mosaics and particularly in riverine or gallery forest throughout the savanna biome.
Vervets are extremely adaptable opportunistic generalists (similar to baboons, but
less so) that easily move into disturbed areas, including agricultural areas, lodges
and can even be found in specialised habitats such as mangrove swamps (Oates,
1996; Kingdon, 1997; Fedigan & Fedigan, 1988; Skinner & Smithers, 1990; Booth,
1979).
2.3 Previous studies on vervets
The general ecology of the vervet monkey (Chlorocebus aethiops) has been widely
studied. Available information refers mostly to the species in East Africa, with less
information available for Central Africa, West Africa and the Southern African Sub
region.
East Africa:
Crucial aspects of vervet ecology were investigated on Lolui Island (Lake Victoria)
by Moreno-Black & Maples (1977). In the Amboseli Game Reserve (Kenya), Lee
et al. (1986), Struhsaker (1967) and Cheney & Seyfarth (1992) did research on
vervet habitat use and preferences, diet, habits and behaviour. Brennan et al.
(1985) studied the ecology and behaviour of vervets in a tourist-lodge habitat in
Amboseli, Kenya. The study revealed that human food played an important role in
the survival of the troop living close to the lodge.
Increased aggression was
observed and human-animal conflict occurred frequently. Changes to the time
budgets of a troop of vervets living in a tourist and cultivated area in Entebbe,
Uganda was investigated by Saj et al. (1999).
Results revealed that the time
budgets of provisioned vervet troops differed in that high proportions of time were
spent resting and low proportions of time were spent feeding.
13
Lee et al. (1986) also focused on vervet interactions with humans. A study on
habitat utilisation and preferences, spatial distribution and feeding habits was
conducted at Diani Beach Forest (Kenya) by Moreno-Black & Maples (1977). Both
Wrangham & Waterman (1981) and Whitten (1988) did research on the feeding
behaviour of vervets in Kenya.
Wrangham & Waterman (1981) did their research in Amboseli and concentrated on
the feeding behaviour of vervets on Acacia tortilis and A. xanthophloea with
specific emphasis on reproductive strategies and tannin production. They found
that the quality of diet has important long-term consequences for the behavioural
ecology and population dynamics of vervets in Amboseli, and that tannins do play
a significant role in shaping the diets of vervets. Whitten (1988) studied the effects
of patch quality and feeding subgroup size on feeding success in vervet monkeys
and provided some evidence to support the hypothesis that patch quality
significantly influences foraging success, also it was suggested that individual
differences in benefits and costs of group foraging may play an important role in
the history and evolution of groups.
The long term consequences of changes in territory quality on feeding and
reproductive strategies of vervets was researched in Kenya by Lee & Hauser
(1998), it was found that the diets of vervets were related to dynamic changes in
their environment and that habitat deterioration resulted in local group extinction
over the medium term. Food properties and contest competition in vervets and
patas monkeys was investigated in Laikipia, Kenya by Pruetz & Isbell (1999).
Results showed that foods which were clumped in their spatial distribution and
which were characterized by long food-site depletion times were food types which
monkeys were most likely to contest.
Aspects of vervet behaviour, population
structure and population dynamics in Amboseli Game Reserve were dealt with by
Cheney et al. (1981) and Cheney & Seyfarth (1983, 1986, 1992).
14
Interspecific relationships and niche separation among coexisting primates of the
Bole Valley (Ethiopia) were examined by Dunbar & Dunbar (1974).
Data on vervet occurrence and ecology are available for Ethiopia, Eritrea, and
Somalia (Yalden et al., 1977, 1996; Nievergelt, 1981).
Central and West Africa:
The vervets’ ecology has been poorly studied in this part of its distribution range.
Harrison (1983) investigated spacing patterns and territorial behaviour in Senegal.
Information on habitat utilisation and preferences in old and secondary growth
forests is reported on by Fimbel (1994), who researched vervet at Tiwai (Sierra
Leone).
Differential habitat utilisation by patas and tantalus monkeys living
sympatrically in northern Cameroon was researched by Nakagawa (1999). Results
revealed that tantalus showed an overall preference for woodland, regardless of
season; whereas patas had a preference for grasslands in the wet season.
Adeyemo (1997) did studies on the diurnal activities of vervets in Old Oyo National
Park, Nigeria and showed that the research subjects were more active in the
mornings and late afternoons, traveling and drinking occurred more in the dry
season than in the wet season, and food supply had an impact on activity patterns
regardless of season. Distribution and ecological data are available for Gabon
(Blom et al., 1992), Ghana (Booth, 1979), Comoé National Park (Ivory Coast)
(Geerling & Bokdam, 1973), and Kwiambana Game Reserve (Nigeria) (Ajayi et al.,
1981).
Southern African Sub region:
Population structure in the Mosi-Oa-Tunya National Park (Zambia) was analysed
by Tembo (1994). Some data on vervet density in relation to water availability in
the Zambesi woodland (Zimbabwe) are reported in Dunham (1994).
Data on
vervet existence in the Sioma-Ngwezi Park (Zambia) are found in Tembo (1995).
15
Most of the aforementioned authors also give some information on the ecology of
the species.
Diurnal and seasonal variations in vervet monkey activity patterns was researched
in Natal by Baldellou & Adan (1998) and showed seasonal diurnal variations to
activity patterns related to climatic constraints and metabolic requirements. Henzi
(1982), did research on visual signaling and social organization in vervets,
comparing data obtained from three free-ranging and one caged troop in Natal,
South Africa with similar data from other localities and in other species. Results
are similar to those recorded in East Africa and it was concluded that Natal vervets
use fewer visual signals than do other species living in more open habitat.
Information on vervet distribution is available for most of South Africa (Pringle,
1974; Bruton, 1978; De Graaff & Rautenbach, 1983; Lynch, 1983, 1989; Skinner &
Smithers, 1990) and northern Namibia (Viljoen, 1982). General information on
vervet ecology and distribution is reported by several authors (Eisenberg et al.,
1972; Struhsaker, 1979; Fedigan & Fedigan, 1988; Lernould, 1988; Skinner &
Smithers, 1990; Estes, 1992; Kingdon, 1997; Mills & Hes, 1997; Stuart & Stuart,
1997). Its status and distribution are discussed by Skinner & Smithers (1990) and
Oates (1996).
From the above it is apparent that not many studies have been carried on vervet
ecology in temperate sub-tropical areas, emphasizing the need for this study.
16
REFERENCES
ADEYEMO, A.I.
1997.
Diurnal activities of green monkeys Cercopithecus
aethiops in Old Oyo National Park, Nigeria. S. Afr. J. Wildl. Res, 27(1): 2426.
AJAYI, S.S., AFOLAYAN, T. & MILLIGAN, K.
1981.
A survey of wildlife in
Kwiambana Game Reserve, Nigeria. Afr. Jnl. Ecol, 19: 295-298.
BALDELLOU, M. & ADAN, A. 1998. Diurnal and seasonal variations in vervet
monkeys’ activity. Psychological Reports, 83(2): 675-85.
BRENNAN, E.J., ELSE, J.G. & ALTMANN, J. 1985. Ecology and behaviour of a
pest primate: vervet monkeys in a tourist-lodge habitat. Afr. J. Ecol, 23: 3544.
BLOM, A., ALERS, M.P.T., FEISTNER, A.T.C., BARNES, R.F.W. & BARNES, K.L.
1992. Primates in Gabon - current status and distribution. Oryx, 26(4): 223234.
BOOTH, A.H. 1979. The Distribution of Primates in the Gold Coast. In: Sussman,
R.W.
(Ed.).
Primate Ecology.
Problem-oriented field studies.
Wiley,
Chichester & New York: chap. 7: 139-154.
BRUTON, M.N.
1978.
Recent mammal records from eastern Tongaland in
Kwazulu, with notes on Hippopotamus in lake Sibaka. Lammergeyer, 24: 1927.
17
CHENEY, D.L., LEE, P.C. & SEYFARTH, R.M. 1981. Behavioural correlates of
non-random mortality among free-ranging female vervet monkeys. Behav.
Ecol. Sociobiol, 9: 153-161.
CHENEY, D.L. & SEYFARTH, R.M. 1983. Nonrandom dispersal in free-ranging
vervet monkeys: social and genetic consequences. Am. Nat, 122(3): 392412.
CHENEY, D.L. & SEYFARTH, R.M. 1986. The recognition of social alliances by
vervet monkeys. Anim. Behav, 34: 1722-1731.
CHENEY, D.L. & SEYFARTH, R.M. 1992. How Monkeys See the World – Inside
the Mind of Another Species. Chicago: University of Chicago Press.
COLLINS ENGLISH DICTIONARY & THESAURUS. 1992. vs 1.5. Harper Collins.
DE GRAAFF, G. & RAUTENBACH, I.L. 1983. A survey of mammals in the newly
proclaimed Karoo National Park, South Africa. Ann Mus Roy Afr Cent, 237:
89-99.
DUNBAR, R. & BARRETT, L. 2000. Cousins: Our Primate Relatives. London:
BBC Worldwide Ltd.
DUNBAR, R.I.M. & DUNBAR, E.P.
1974.
Ecological relations and niche
separation between sympatric terrestrial primates in Ethiopia. Folia Primatol,
21: 36-60.
DUNHAM, K.M. 1994. The effect of drought on the larger mammal populations of
Zambezi riverine woodlands. Jnl. Zool, 234(3): 489-526.
18
EISENBERG, J.F., MUCKENHIRN, N. & RUDRAN, R.
1972.
The relations
between ecology and social structure in primates. Science, 176: 863-874.
ESTES, R.D.
1992.
Behaviour Guide to African Mammals.
Los Angeles:
University of California Press.
FEDIGAN, L. & FEDIGAN, L.M. 1988. Cercopithecus aethiops: a review of field
studies. In: Gautier-Hion A., Bourlière F., Gautier J., Kingdon J. (Eds). A
Primate Radiation: Evolutionary Biology of the African Guenons. Cambridge
University Press, New York: pp 389-411.
FIMBEL, C. 1994. The relative use of abandoned farm clearings and old forest
habitats by primates and a forest antelope at Tiwai, Sierra Leone, West
Africa. Biological Conservation, 70: 277-286.
GEERLING, G. & BOKDM, J. 1973. Fauna of the Comoé National Park, Ivory
Coast. Biological Conservation, 5(4): 251-257.
HARRISON, M.J.S.
1983.
Territorial behaviour in the green monkey,
Cercopithecus sabaeus: seasonal defence of local supplies. Behav. Ecol.
Sociobiol, 12: 85-94.
HENZI, S.P. 1982. Some aspects of visual signaling and social organization in the
vervet monkey (Cercopithecus aethiops pygerthrus).
Ph.D. dissertation.
University of Natal.
KINGDON, J. 1997. The Kingdon field guide to African Mammals. Academic
Press, New York: Natural World.
19
LEE, P.C., BRENAN, J.P., ELSE, J.G. & ALTMAN, J.
1986.
Ecology and
behaviour of vervet monkeys in a tourist lodge habitat. In: Else J.G., Lee P.C.
(Eds). Primate ecology and conservation. Selected Proceedings of the 10th
Congress Int. Primatological Society, Nairobi, Kenya (July 1984). Cambridge
University Press, Cambridge, U.K: chap. V.3, 229-236.
LEE, P.C. & HAUSER, M.D.
1998.
Long-term consequences of changes in
territory quality on feeding and reproductive strategies of vervet monkeys.
Journal of Animal Ecology, 67: 347-358.
LERNOULD, J. 1988. Classification and geographical distribution of guenons: a
review. In: Gautier-Hion A., Bourlière F., Gautier J., Kingdon J. (Eds). A
Primate Radiation: Evolutionary Biology of the African Guenons. Cambridge
University Press, New York.
LYNCH, C.D. 1983. The mammals of the Orange Free State. Mem. van die
Nasionale Mus, 18: 1-218.
LYNCH, C.D. 1989. The mammals of the north-east Cape Province. Mem. van
die Nasionale Mus, 25: 1-116.
MILLS, G. & HES, L. 1997. The complete book of Southern African mammals.
Struik Publishers.
MORENO-BLACK, G.S. & MAPLES, W.R. 1977. Differential habitat utilisation of
four Cercopithecidae in a Kenyan forest. Folia Primatol, 27: 85-107.
20
NAKAGAWA, N.
1999.
Differential habitat utilisation by Patas monkeys
(Erythrocebus patas) and Tantalus monkeys (Cercopithecus aethiops
tantalus) living sympatrically in northern Cameroon.
American Journal of
Primatology, 49: 243-264.
NIEVERGELT, B. 1981. Ibexes in an African Environment. Ecology and social
system of the Walia Ibex in the Simen Mountains, Ethiopia. Springer Verlag:
Berlin and New York Ecology Studies.
OATES, J.F. 1996. African Primates Status Survey and Conservation Action plan.
IUCN/SSC Primate Specialist Group. S.I.
PRINGLE, J.A. 1974. The distribution of mammals in Natal. Part I. Primates,
Hyracoidea, Lagomorpha (except Lepus), Pholidota and Tubulidentata. Ann.
Natal Mus, 22(1): 173-186.
PRUETZ, J.D. & ISBELL, L.A. 1999. What makes a food contestable? Food
properties and contest competition in vervets and patas monkeys in Laikipia,
Kenya. American Journal of Physical Anthropology, 28: 225-226.
SAJ, T., SICOTTE, P. & PATERSON, J.D.
1999.
Influence of human food
consumption on the time budget of vervets. Int. J. Primatology, 20: 977-994.
SKINNER, J.D. & SMITHERS, R.H.N.
nd
African Subregion. 2
STRUHSAKER, T.T.
1990.
The Mammals of the Southern
ed. South Africa: University of Pretoria.
1967.
Auditory Communication Among Vervet Monkeys
(Chlorocebus aethiops). In: Social Communication among Primates, ed. S.A.
Altmann. University of Chicago Press.
21
STRUHSAKER, T.T. 1979. Correlates of ecology and social organisation among
African cercopithecines. In: Primate Ecology, ed. R.W. Sussman. Problemoriented field studies. Wiley, Chichester & New York: chap. 20: 391-404.
STUART, C. & STUART, T. 1997. Field guide to the larger mammals of Africa.
Struik Publishers, Cape Town.
TEMBO, A. 1994. Population characteristics of the vervet monkey in the Mosi-OaTunya National Park, Zambia. Afr. Jnl. Ecol, 32: 72-74.
TEMBO, A. 1995. A survey of large mammals in Sioma-Ngwezi Park, Zambia.
Afr. Jnl. Ecol, 33: 173-174.
VILJOEN, P.J.
1982.
The distribution and population status of the larger
mammals in Kaokoland, South West Africa/Namibia. Cimbebasia, A7: 7-33.
WHITTEN, P.L.
1988. Effects of patch quality and feeding subgroup size on
feeding success in vervet monkeys (Cercopithecus aethiops).
Behaviour,
105: 35-52.
WILSON , D.E. & REEDER, D.M. (eds.). 1993. Mammal Species of the World: A
Taxonomic and Geographic Reference.
2nd ed.
Smithsonian Institution
Press, Washington D.C.
WRANGHAM, R.W. & WATERMAN, P.G. 1981. Feeding behaviour of vervet
monkeys on Acacia tortilis and Acacia xanthophloea with special reference to
reproductive strategies and condensed tannin production. J. Anim. Ecol, 50:
715-731.
22
YALDEN, D.W., LARGEN, M.J. & KOCK, D. 1977. Catalogue of the mammals of
Ethiopia 3. Primates. Monitore Zoologico Italiano, suppl, IX: 1-52.
YALDEN, D.W., LARGEN, M.J., Kock, D. & HILLMAN, J.C. 1996. Catalogue of
the mammals of Ethiopia and Eritrea. 7. Revised checklist, zoogeography
and conservation. Tropical Zoology, 9: 73-164.
23
CHAPTER 3
STUDY SITE
3.1 Location, size and topography
The Blydeberg Conservancy is located along the great escarpment in the
Northern Province, Longitude 30° 27’ to 25° 56’ E and Latitude 24° 23’ to 24°
28’ S. Altitude ranges from 350 m to 800 m above sea level (Bredenkamp &
Van Rooyen, 1998a, 1998b). The study area constitutes the farms Dunstable
(farm number 230) and Jongmanspruit (farm number 234) (Figure 2).
Figure 2:
Location of the study area within the Northern province of South
Africa. The study area is demarcated with a rectangle.
The size of the Blydeberg conservancy is approximately 3000 ha, with the
study area being 816 ha.
24
The topography of the study area is mountainous in the south to flat and
open in the north. There are several small mountain streams running from
the watershed in the Drakensberg Mountains in the south into the Blyde River
to the north of the conservancy.
Within the Blydeberg Conservancy there were areas that were off limits
during the study. Such areas were private property where hunting occurred.
Areas to the east and west of the demarcated study area (yellow rectangle in
Figure 3) were such off limit zones.
25
Figure 3:
A GPS generated vector map of roads and infrastructure in
Blydeberg Conservancy depicting the study area within the
confines of the yellow rectangle and GPS mapped roads overlaid
onto a digitized aerial photo of Blydeberg Conservancy.
26
3.2 Geology
The geology of the central and southern sections of the study area are a
combination of volcanic and sedimentary rocks from the Black Reef formation
of the Transvaal Sequence, from the Selati Formation of the undifferentiated
upper part of the Wolkberg Group, and from the Abel Erasmus formation of
the undifferentiated lower part of the Wolkberg Group; all dating back to the
Vaalian Quaternary (Visser, 1989; Walraven, 1989; Buckle, 1992).
The
geology of the northern section of the study area is rock of intrusive origin,
dating back to the Swazian Quaternary (Visser, 1989; Walraven, 1989;
Buckle, 1992).
The geology of the study area ranges from a zone of fine to medium grained
quartzite, gritty in places with pebble layers, basic lava, tuff, agglomerate and
shale (lithologically classified as Vbr) in the South, to a zone of light-grey,
medium
grained
biolite
gneiss
with
coarse-grained
quartz-feldspar
leucosomes; recrystallised in places (lithologically classified as Zm) in the
North (Figure 4) (Visser, 1989; Walraven, 1989).
An intermediate zone of
laminated micaceous and graphitic shale, locally interlayered with sandy shale,
flagstone and quartzite (lithologically classified as Vwe) separates the southern
Vbr and northern Zm zones (Figure 4) (Visser, 1989; Walraven, 1989). Also,
according to Visser (1989) and Walraven (1989), intermittently layered along
the south of the northern Zm zone and between such and the Vwe
intermediate zone is another less distinct zone of greenish grey intermediate
lava, amygdaloidal in places, interbedded porphyritic layers and layers of shale
and quartzite (lithologically classified as Vwa) (Figure 4).
27
Study Area
Figure 4:
Geological map of the study area (demarcated by the yellow
rectangle) and surrounds as adapted from the 1:250 000
Geological Series 2430 for Pilgrims Rest (South Africa, 1986).
Vbr, Vwe and Vwa are rocks of volcanic and sedimentary origin (Figure 4)
(Visser, 1989; Walraven, 1989; Buckle, 1992). Vbr originates from the Black
Reef formation of the Transvaal Sequence dating back to the Vaalian
Quaternary. Vwe originates from the Selati Formation of the undifferentiated
upper part of the Wolkberg Group dating back to the Vaalian Quaternary.
Vwa originates from the Abel Erasmus Formation of the undifferentiated lower
part of the Wolkberg Group and also dates back to the Vaalian Quaternary.
Zm is rock of intrusive origin, dating back to the Swazian Quaternary (Figure
4) (Visser, 1989; Walraven, 1989; Buckle, 1992).
28
3.3 Land Types
Four land types, namely Fa, Fb, Ib and Ic occur in the study area as indicated
in the terrain form sketch (Figure 5). According to Land Type Survey Staff
(1989), “A land type denotes an area that can be shown at 1:250 000 scale
and displays a marked degree of uniformity with respect to terrain form, soil
pattern and climate”.
A close association between the major plant
communities and the different land types has been observed in other studies
(Kooij et al., 1990; Bezuidenhout, 1993; Eckhardt, 1993; Brown, 1997).
The F land type refers to pedologically young landscapes that are not
predominantly rock and alluvial or aeolian; in which the main soil forming
processes have been rock weathering (Land Type Survey Staff, 1989). The
formation of orthic topsoil horizons and clay illuviation have typically given rise
to lithocutanic horizons (Land Type Survey Staff, 1989). Dominant soil forms
are Glenrosa and Mispah, with Oakleaf present in upland areas (Soil
Classification Working Group, 1991).
In the Fa land type lime in the soil is not commonly encountered and is rare or
absent throughout the landscape. This land type consists of two terrain units,
midslopes comprising 95 % of the land type, and valley bottoms constituting
the remaining 5 % of the land type. Terrain type is D5, with less than 20 % of
the area having slopes less than 8 %. Local relief varies from 300 to 900 m.
Midslopes slope range varies between 6-30 % with range of slope length
varying between 500-2000 m. Soil forms found on midslopes include Msinga
(30 %), Mispah (20 %) and Trevanian (10 %). Rockiness is estimated at 40
%.
29
Valley bottoms slope range varies between 2-10 % with range of slope length
varying between 10-40 m. Soil forms found in valley bottoms include Mispah
(15 %), Trevanian (10 %), Waterridge and Cartref Series (20 %). Rockiness
is estimated at 30 %, with stream beds comprising 25 % of the landscape.
Soils are mostly medium sandy loam to sandy clay loam (Soil Classification
Working Group, 1991).
Soils are shallower than 400 mm.
The geology
consists of shale, quartzite, conglomerate and basalt of the Wolkberg group,
Transvaal Sequence (Land Type Survey Staff, 1989).
In the Fb land type, lime in the soil is rare or absent in upland areas but,
generally lime is present in low-lying areas. This land type consists of two
terrain units, foot slopes comprising 80 % of the land type, and valley bottoms
constituting 20 % of the land type. Terrain type is B3, with 50–80 % of the
area having slopes less than 8 %. Local relief varies from 90 to 150 m. Foot
slopes slope range varies between 4-10 % with range of slope length varying
between 500-2500 m. Soil forms found on foot slopes include Cartref and
Kusasa Series (20 %), Nyoka and Lindley Series (10 %), Shorrocks (10 %),
Springfield (10 %), and Glenrosa (5 %). Soil rock complexes include Mispah
(10 %), Platt and Glenrosa Series (20 %), and Shorrocks (5 %).
Soil
rockiness is estimated at 10 %. Valley bottoms slope range varies between
2-4 % with range of slope length varying between 50-100 m. Soil forms found
in valley bottoms include Nyoka and Lindley Series (20 %), and Balfour and
Darling Series (60 %). Rockiness is estimated at 5 %, with stream beds
comprising 15% of the landscape. Soils are mostly medium to coarse sand to
loamy sand (Soil Classification Working Group, 1991). Soils are shallower
than 1200 mm.
The geology consists of unnamed potassic granite and
granodiorite (Land Type Survey Staff, 1989).
The I land type refers to miscellaneous land classes (Land Type Survey Staff,
1989).
30
The land type Ib indicates land types with exposed rock (country rock, stones
or boulders), which covers 60-80 % of the area. This land type consists of
three terrain units, namely crests comprising 20 % of the land type, midslopes
comprising 75 % of the land type, and valley bottoms constituting the
remaining 5 % of the land type. Terrain type is D5, with less than 20 % of the
area having slopes less than 8 %. Local relief varies from 300 to 900 m. The
slope range of crests varies between 2-6 % with range of slope length varying
between 20-100 m.
Soil forms found on crests include Farningham and
Hutton Series (20 %).
Soil rock complexes include Mispah (10 %),
Williamson, Trevanian and Sainfaiths Series (20 %).
Soil rockiness is
estimated at 50 %. Midslopes slope range varies between 10-60 % with
range of slope length varying between 100-1000 m. Soil forms found on
midslopes include Farningham and Hutton Series (5%). Soil rock complexes
include Mispah (15 %), Williamson, Trevanian and Sainfaiths Series (10 %).
Soil rockiness is estimated at 70 %.
Valley bottoms slope range varies
between 2-4 %, with range of slope length varying between 10-50 m. Soil
forms found in valley bottoms include Cranbrook (10 %), and Jozini (10 %).
Soil rock complexes include Williamson, Trevanian and Sainfaiths Series (20
%). Soil rockiness is estimated at 50 %, with stream beds comprising 10 % of
the landscape. Soils are mostly medium sandy clay loam to sandy clay (Soil
Classification Working Group, 1991). Soils are shallower than 900 mm. The
geology consists of quartzite, conglomerate, shale and basalt of the Black
Reef Formation, Transvaal Sequence (Land Type Survey Staff, 1989).
The land type Ic refers to land types with exposed rock (country rock, stones
or boulders), covering more than 80 % of the area. This land type consists of
four terrain units, crests comprising 10 % of the land type, scarps comprising
20 % of the land type, midslopes comprising 68 % of the land type, and valley
bottoms constituting the remaining 2 % of the land type.
31
Terrain type is D5, with less than 20 % of the area having slopes less than 8
%. Local relief varies from 300 to 900 m. Crests slope range varies between
4-15 % with range of slope length varying between 50-100 m. Soils rock
complexes found on crests include Mispah (25 %), Williamson and Trevanian
Series (10 %), and Msinga (10 %). Soil rockiness is estimated at 55 %.
Scarps slope range varies between 90-150 % with range of slope length
varying between 50-150 m. Soil rock complexes found on scarps include
Mispah (5 %). Soil rockiness is estimated at 95 %.
Midslopes slope range
varies between 8-50 % with range of slope length varying between 200-800
m. Soil forms found on midslopes include Mispah (5 %), Williamson and
Trevanian Series (5 %), and Msinga (5 %). Soil rockiness is estimated at 85
%.
Valley bottoms slope range varies between 4-8 % with range of slope length
varying between 10-40 m. Soil forms found in valley bottoms include Mispah
(5 %), and Msinga (5 %). Soil rockiness is estimated at 85 %, with stream
beds comprising 5 % of the landscape. Soils are mostly fine to medium
sandy loam to sandy clay loam (Soil Classification Working Group, 1991).
Soils are shallower than 300 mm. The geology consists of shale, quartzite,
conglomerate and basalt of the Wolkberg Group, Transvaal Sequence (Land
Type Survey Staff, 1989).
32
a)
b)
c)
d)
Figure 5:
Terrain form sketch indicating the various land types of the study
area. a) is land type Fa, b) is land type Fb, c) is land type Ib, and
d) is land type Ic.
Within the land type sketches, 1=Crest,
2=Scarp, 3=Mid slope, 4=Foot slope, 5=Valley bottom.
33
3.4 Climate
According to Bredenkamp & Van Rooyen (1998a, 1998b), the rainfall for the
region encompassing the study area varies between 450 mm to 1000 mm per
annum with temperatures ranging between -4 to 45 °C with a daily mean of
21 to 22° C.
Annual rainfall and temperature for Blydeberg for the four years preceding the
study period was obtained from the Agricultural Research Council (ARC)
institute for tropical and sub-tropical crops in Nelspruit.
Climatic data
collected over the study period was combined with ARC data for analyses.
Rainfall and temperature figures for the same period for the Hoedspruit area
was obtained from local farmers. Only five years of climatic data were used
for analysis due to records from local farmers not being accurate for longer
periods.
The average annual rainfall for the study area, as measured by a weather
station situated on the Jongmanspruit farm for the period 05/1999 to 04/2004
was 561 mm, with a high of 953 mm and a low of 255 mm recorded in 2000
and 2002 respectively. For the period 05/1999 to 04/2004, average monthly
rainfall varied from 0.7 mm during the dry winter season (May to October) to
106 mm in the wet summer season (November to April) (Figure 6).
For the larger Hoedspruit region, average annual rainfall for the period
05/1999 to 04/2004 was 900 mm with a high of 1463 mm and a low of 629
mm recorded in 2000 and 2002 respectively.
For the period 05/1999 to
04/2004, average monthly rainfall varied from 2 mm during the dry winter
season (May to October) to 189 mm in the wet summer season (November to
April) (Figure 6).
34
Rainfall recorded for the study area is less than for the larger Hoedspruit
region due to the study areas location on the foothills of the Drakensberg
Mountains along the great escarpment. The mountains form a barrier leading
to a rain shadow which could be responsible for less rainfall in the study area.
However, the mountains do function as an important catchment for the study
area and are the source of several small mountain streams (Van Zyl, 2003).
Locally thunderstorms and fog are the main sources of precipitation for the
study area.
Average annual temperature for the study area for the period 05/1999 to
04/2004 was 22oC, with mean temperatures varying from 17oC during the dry
winter season to 26oC in the wet summer season (Figure 6).
A minimum temperature of 3oC and a maximum of 42oC were recorded in the
05/2003 to 04/2004 period.
Average annual temperature for the larger Hoedspruit region for the period
05/1999 to 04/2004 was 17oC, with mean temperatures varying from 11oC
during the dry winter season to 23oC in the wet summer season (Figure 6). A
minimum temperature of 11oC and a maximum of 23oC were recorded in the
05/2003 to 04/2004 period.
Temperatures for the study area are higher than those for the larger
Hoedspruit region due to the study area lying along the north facing foot
slopes of the Drakensberg Mountains along the great escarpment. The study
area has more direct exposure to sunlight and is more sheltered from
southerly winds than the surrounding areas (Tyson & Preston-Whyte, 2000).
35
200
180
160
140
120
100
80
60
40
20
0
Temperature ( o C)
25
20
15
10
5
0
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
Month
Figure 6:
Avg Temp - Hoedspruit 99-04
Avg Temp - Blydeberg 99-04
Avg Rainfall - Hoedspruit 99-04
Avg Rainfall - Blydegerg 99-04
Average monthly rainfall and temperatures for Blydeberg
Conservancy and Hoedspruit from 05/1999 to 04/2004.
Temperature and rainfall depicted in Figure 6 do not accurately represent
monthly variations over the study period for the study area; hence a
breakdown by month was created (Figure 7).
According to Figure 7, the coldest months at Blydeberg were June 2003 to
August 2003, and the hottest were December 2003 to February 2004. No
rainfall was recorded for July and August 2003, with only 2.5 mm recorded for
October 2003. The highest rainfall of 136.5 mm was recorded in March 2004,
with January and February 2004 being slightly less at 118.4 mm and 121.4
mm respectively.
36
Rainfall (mm)
30
160
30
136.5
118.4 121.4
Rainfall (mm)
120
25
100
20
80
15
60
44.8
42
38
40
20
9.5
14.7
0
0
6.8
2.5
5
0
-20
10
Temperature (deg C)
140
May- Jun- Jul-03 Aug- Sep- Oct- Nov- Dec- Jan- Feb- Mar- Apr03
03
03
03
03
03
03
04
04
04
04
0
Months
Total rainfall
Figure 7:
Average temperature
Average rainfall
Rainfall and temperature summary for the study period 01 May
2003 to 30 April 2004 for the study area.
Table 1 depicts a rainfall summary for the last five years with a breakdown for
the study period. Total rainfall for the first three quarters of the study period
(238.7 mm) was less than rainfall for the fourth quarter (295.9 mm). From
Table 1 it can be seen that the study period was mostly a dry period, with
more than half (295.9 mm) of the total (534.6 mm) rainfall having fallen during
the fourth quarter. The fourth quarter’s rainfall as a percentage of the actual
was 55.3 %, with the first to third quarters totaling only 44.7 %.
To further emphasize the above, the second half of the study period had 93.7
% of the total rainfall, as opposed to 6.3 % for the first half of the study period.
The year before the study period was also a dry period, with only 254.6 mm of
rain recorded for the year.
37
Rainfall during the study period was erratic and voluminous over short
periods, with thunderstorms being the main source thereof.
During
thunderstorms large quantities of rain fell over very short periods of time, with
most rainfall ending up as runoff and not much seepage.
Table 1:
Rainfall for the last five years with a breakdown for the study
period.
Actual Mean
Period
(mm)
(mm) % of Actual Comment
05/1999-04/2000
953.3
79.4 n/a
n/a
05/2000-04/2001
467.1
38.9 n/a
n/a
05/2001-04/2002
595.3
49.6 n/a
n/a
05/2002-04/2003
254.6
21.2 n/a
n/a
05/2003-04/2004
534.6
44.6 n/a
n/a
1st quarter 05/2003-07/2003
24.2
2.0
4.5 Below mean
2nd quarter 08/2003-10/2003
9.3
0.8
1.7 Below mean
3rd quarter 11/2003-01/2004
205.2
17.1
38.4 Below mean
4th quarter 02/2004-04/2004
295.9
24.7
55.3 Above mean
1st half 05/2003-10/2003
33.5
2.8
6.3 Below mean
2nd half 11/2003-04/2004
501.1
41.8
93.7 Above mean
3.5 Flora
The conservancy’s vegetation falls within the Mixed Lowveld Bushveld vegetation type No. 19 (Bredenkamp & Van Rooyen, 1998a) and Sour
Lowveld Bushveld - vegetation type No. 21 (Bredenkamp & Van Rooyen,
1998b); or within the Arid Lowveld (Acocks veld type No. 11) (Acocks, 1988).
38
The aforementioned veld types have high plant species richness with more
than one thousand plant species recorded in the nearby Blyde River Canyon
Nature Reserve. A checklist of all plant species recorded during this study for
the Blydeberg Conservancy and the study area is attached (Appendix 1).
Adjacent to the conservancy, especially in the valleys, are cultivated
agricultural lands containing sub-tropical fruits which include mangoes,
bananas, papayas, oranges, vegetables and sugar cane.
For a comprehensive analysis of the study areas vegetation refer to Chapter
5.
3.6 Fauna
Several bird species including the martial eagle (Polemaetus bellicosus) and
the crowned eagle (Stephanoaetus coronatus), which are known predators of
vervets are frequently seen flying over the Blydeberg Conservancy.
Mammals found on the Conservancy include aardvark (Orycteropus afer),
baboon (Papio ursinus), banded mongoose (Mungos mungo), black backed
jackal (Canis mesomelas), common duiker (Sylvicapra grimmia), blue
wildebeest
(Connochaetes
taurinus),
thick-tailed
bushbaby
(Otolemur
crassicaudatus), bushbuck (Tragelaphus scriptus), caracal (Felis caracal),
rock hyrax (Procavia capensis), giraffe (Giraffa camelopardalis), honey
badger
(Mellivora
capensis),
impala
(Aepyceros
melampus),
kudu
(Tragelaphus strepsiceros), leopard (Panthera pardus), porcupine (Hystrix
africaeaustralis), scrub hare (Lepus saxatilis), slender mongoose (Gelerella
sanguinea), large spotted genet (Genetta tigrina), vervet (Chlorocebus
aethiops),
warthog
(Phacochoerus
aethiopicus),
ellipsiprymnus), and burchell’s zebra (Equus burchelli).
39
waterbuck
(Kobus
Wild dog (Lycaon pictus) and cheetah (Acinonyx jubatus) have been known
to pass through the Conservancy from time to time, but are not resident.
Invertebrates are well represented and include several families.
A variety of frog and toad species occur in mountain streams and pools, and
include the platanna (Xenopus laevis laevis), red toad (Bufo carens), common
rain frog (Breviceps mossambicus adspersus), red-backed grass frog
(Ptychadena
superciliaris),
painted
reed
frog
(Hyperolius
viridiflavus
taeniatus), and common rana (Rana angolensis).
Snakes are well represented with the black mamba (Dendroaspis polylepis),
mozambique spitting cobra (Naja mossambica), common night adder
(Causus rhombeatus), twig or vine snake (Thelotornis capensis), stiletto
snake (Atractaspis bibronii), southern African rock python (Python sebae),
boom slang (Dispholidus typus), and puff adder (Bitis arietans) being the most
noteworthy dangerous snakes.
Several lizards and geckos are present
throughout the area.
40
REFERENCES
ACOCKS, J.P.H. 1988. Veld types of South Africa.
3rd ed. Mem. Bot. Surv. S.
Afr. 40, Government Printer, Pretoria.
BEZUIDENHOUT, H. 1993. Syntaxonomy and synecology of Western Transvaal
Grasslands. Ph.D. dissertation, University of Pretoria, Pretoria.
BREDENCAMP, G. & VAN ROOYEN, N. 1998a. Mixed Lowveld Bushveld. In:
Low, A.B. & Rebelo, A.G. (eds) Vegetation of South Africa, Lesotho and
Swaziland. 2nd ed. Dept Environmental Affairs and Tourism, Pretoria.
BREDENCAMP, G. & VAN ROOYEN, N. 1998b. Sour Lowveld Bushveld. In:
Low, A.B. & Rebelo, A.G. (eds) Vegetation of South Africa, Lesotho and
Swaziland. 2nd ed. Dept Environmental Affairs and Tourism, Pretoria.
BROWN, L.R.
1997.
A plant ecological and wildlife management plan of the
Borakalalo Nature Reserve, North-west Province.
Ph.D.
dissertation.
University of Pretoria, Pretoria.
BUCKLE, C.
1992.
Landforms in Africa: An Introduction to Geomorphology.
Essex: Longman Group Ltd.
ECKHARDT, H.C. 1993. A synecological study of the vegetation of the northeastern Orange Free State. M.Sc. thesis. University of Pretoria, Pretoria.
KOOIJ, M.S., BREDENKAMP, G.J. & THERON, G.K. 1990. Classification of the
vegetation of the B land type in the north-western Orange Free State. South
African Journal of Botany, 56: 309-318.
41
LAND TYPE SURVEY STAFF. 1989. Land types of the maps 2330 Tzaneen,
2430 Pilgrims Rest. Memoirs on the Agricultural Natural Resources of South
Africa, 12.
SOIL CLASSIFICATION WORKING GROUP.
taxonomic system for South Africa.
1991.
Soil classification a
Memoirs on the Agricultural Natural
Resources of South Africa, 15: 1-257.
SOUTH AFRICA (REPUBLIC). 1986. 1:250 000 Geological Series 2430 Pilgrims
Rest. Government Printer, Pretoria.
TYSON, P.D. & PRESTON-WHYTE, R.A. 2000. The Weather and Climate of
Southern Africa. Cape Town: Oxford University Press.
VAN ZYL, D.
2003.
South African Weather and Atmospheric Phenomena.
Pretoria: Briza Publications.
VISSER, D.J.L. (ed.).
1989.
The Geology of the Republics of South Africa,
Transkei, Bophuthatswana, Venda and Ciskei and the Kingdoms of Lesotho
and Swaziland.
Geological Survey, Explanation of the 1: 1 000 000
Geological Map, 4th ed. Government Printer, Pretoria.
WALRAVEN, F.
1989.
The Geology of the Pilgrim’s Rest Area.
Survey, Explanation of Sheet 2430. Government Printer, Pretoria.
42
Geological
CHAPTER 4
METHODS
This dissertation consists of a series of reports on the vegetation, vervet troop
seasonal habitat utilisation and food selection, and seasonal activity patterns within
the study area. The specific methods used in each data chapter (chapters 5, 6 and
7) are presented in each report. This chapter is a more detailed presentation of the
general methods applied to this study.
4.1 Vegetation mapping and habitat description
One of the main objectives for this study was to identify, classify and describe
the different plant communities within the study area. In order to compile
such an ecological classification, the Zurich-Montpellier approach or the so
called ‘Braun-Blanquet’ method was used (Braun-Blanquet, 1932; MuellerDombois & Ellenberg, 1974; Westhoff & Van der Maarel, 1978). The BraunBlanquet method satisfies the three basic requirements of a vegetation
ecology study in that it is: 1) scientifically sound, 2) it fulfills the necessity of
classification at appropriate levels, and 3) it is more efficient and versatile
among other comparable methods (Werger, 1974).
Because of the
aforementioned reasons and also due to the Braun-Blanquet methodology
being easy to use, producing a reliable classification of an areas vegetation, it
was decided to use this method for the classification of the study areas
vegetation.
For orientation purposes and to gain knowledge of the study area, it was
necessary to map the existing roads and infrastructure. Such was done with
a Garmin 12 XL GPS and CARTALINX (Hagan et al., 1998) mapping
software.
43
Using a 1:10 000 digitized ortho photo for the Blydeberg area, the study area
was stratified into homogeneous physiognomic-physiographic units based on
geological formations, river banks, steep slopes, hills, valleys and floodplains,
as well as areas with similar vegetation structure and texture (Barbour et al.,
1987; Kent & Coker, 1997). A total of 49 sample plots were located in a
randomly stratified manner within these different stratification units to ensure
all variations in the vegetation were considered and sampled. The number of
plots were determined on a pro-rata basis subjective to the size of the unit,
with more plots placed in the larger units than in the smaller ones. This
subjective approach is often criticized but this strategy ensures that a
statistically acceptable representative sample of the variation is obtained
(Werger, 1974). Plot sizes were fixed at 400 m2 (Barbour et al., 1987; Brown
& Bredenkamp, 1994; Brown, 1997). In each sample plot all plant species
were recorded and cover abundance was assessed using the Braun-Blanquet
cover abundance scale (Mueller-Dombois & Ellenberg, 1974; Barbour et al.,
1987)(Table2). Fieldwork was undertaken during April, May, and June 2003
and in January 2004. In the light of taxon names constantly changing, this
publication conforms to those of Arnold & De Wet (1993).
44
Table 2:
Modified Braun Blanquet cover abundance scale (MuellerDombois & Ellenberg, 1974).
Scale
r
Description
One or few individuals with less than 1 % cover of the total sample plot
area.
+
Occasional and less than 1 % cover of the total sample plot area.
1
Abundant with low cover, or less abundant but with higher cover, 1-5 %
cover of the total sample plot area.
2
Abundant with >5-25 % cover of the total sample plot area, irrespective
of the number of individuals.
2a
>5-12.5 % cover.
2b
>12.5-25 % cover.
3
>25-50 % cover of the total sample plot area, irrespective of the number
of individuals.
4
>50-75 % cover of the total sample plot area, irrespective of the number
of individuals.
5
>75 % cover of the total sample plot area, irrespective of the number of
individuals.
Environmental data collected include aspect, estimates of slope, percentage
rockiness and percentage erosion. Floristic Data were analysed according to
Braun-Blanquet procedures using the TURBOVEG suite (Hennekens, 1998),
which includes the Two-way
indicator species
analysis
multivariate
classification technique (TWINSPAN)(Hill, 1979) for deriving an initial
approximation of the main plant communities. This numerical classification
technique is regarded as a successful approach to vegetation classification
by various phytosociologists (Brown & Bredenkamp, 1994; Bredenkamp &
Bezuidenhout, 1995; Brown et al., 1996; Cilliers, 1998).
45
The visual editor MEGATAB (Hennekens, 1996) was used to generate a
phytosociological table.
Using the phytosociological table and habitat
information collected during sampling in the field, different plant communities
were identified, described and ecologically interpreted. Further refinement of
the classification was undertaken through the application of Braun-Blanquet
procedures (Barbour et al. 1987; Bredenkamp et al. 1989; Kooij et al. 1990;
Bezuidenhout 1993; Eckhardt 1993; Brown & Bredenkamp 1994; Kent &
Coker 1997).
Plant communities were recognized by using diagnostic
species as defined by Westhoff & Van der Maarel (1978).
Diagnostic or
character species are those that are relatively restricted to a community.
These species do not necessarily have a high importance value.
The
different plant communities are described according to their dominant
species.
Dominant species are those that are most conspicuous in the
community and are high in one or more of the importance values (Whittaker,
1978), in this case cover and frequency.
A map of the various vegetation communities occurring within the
conservancy (Ch5 Figure 4) was generated using a GPS and CARTALINX
software (Hagan et al., 1998).
4.2 Vervet monitoring
The study was conducted over a one year period to include at least one wet
and one dry season.
Population structure and demography
Counts of the total vervet population in the Conservancy were obtained from
random searches undertaken every month over the study period, and from
conducting a census of the study area.
46
The location of all troops in the area was mapped as an overlay to the base
map using GPS co-ordinates (Ch6 Figure 6).
Individual animals were
classified according to age class (adults, sub-adults, juveniles and neonates)
and sex (male, female and unknown).
Ecology
A single vervet troop was habituated. The troop was followed on foot from a
distance of 5-15 m for as long as possible on each day of data collection.
Data were collected over an average of eleven days a month for a twelvemonth period (1 May 2003 to 30 April 2004), resulting in 132 days of data, 30
of which were from dawn to dusk, the rest being dependent on when and for
how long the troop was located.
Data were recorded using a PALM
HANDSPRINGTM data-logger, pre-loaded with PENDRAGON FORMSTM
software. Scan samples were taken approximately every thirty minutes from
all visible animals (Altmann, 1974). Five mutually exclusive categories of
activity were recognized: foraging (feeding, actively searching for or
processing food), socializing (playing, aggression, grooming, maternal or
paternal, mating), moving, resting and drinking. Chapter 7 depicts seasonal
variations in the study troop’s activity patterns.
When animals were recorded as foraging, the food source was identified and
the specific part being consumed i.e. root, stem, fruit, flower, seed or leaf was
documented.
4.3 Census
A census of the various species occurring in the study area was undertaken
to determine diversity and numbers of animals. Combinations of the strip/line
transect and known group counts were used.
47
A PALM HANDSPRINGTM data-logger pre-loaded with PENDRAGON
FORMSTM software was used for doing the census.
A MICROSOFT
ACCESSTM form was generated on a desktop computer and exported to the
data-logger for data collection in the field. Collected Data were exported from
the data-logger back to the desktop for analysis and processing.
• Animal Census Protocol
According to Collinson (1985), the methods used for censusing animal
populations needs to be standardized for comparison purposes between
data collected by different individuals in potentially different areas, and for
contingency purposes.
Estimations of distances from animals encountered to the observer during
the census are most likely to vary, and either a measuring tape should be
used (this wasn’t practical) or, more realistically, the individuals conducting
the census should train themselves to estimate distances as accurately as
possible (Barrett, pers. comm., 2003; Henzi, pers. comm., 2003).
• Estimating Distance
Barrett (pers. comm., 2003) and Henzi (pers. comm., 2003), state that
pacing is an effective method of measuring horizontal distances, provided
the terrain is level and unobstructed. Pace length is calculated by counting
one’s steps along a straight pre-measured line and then dividing number of
paces by distance.
After pacing the line several times and regulating ones stride, average
pace length can be determined. Pacing was used to measure distance
between observer and animal.
48
Estimation of horizontal and vertical distances in the census habitat was
done by making visual estimates along measured distances - multiples of
known distances i.e. a person’s height was used and the height of a tree
was estimated as the number of multiples of the height of for example a
1.5 m tall person (Barrett, pers. comm., 2003; Henzi, pers. comm., 2003).
• Timing of Censuses
Censuses were done at approximately the same time of day on census
days i.e. from 07h00 to 11h00, this being consistent with recommendations
for doing censuses (Collinson, 1985). The first 4-6 hours of the morning
and the last 3 hours of the afternoon/evening are ideal for censusing
primates as this is when animals tend to be most active (Barrett, pers.
comm., 2003; Henzi, pers. comm., 2003). No censusing was done during
rainy or very windy conditions, as such reduces visibility and leads to
sample bias.
• Transect Lines
Transect lines were kept as straight as possible, bearing in mind that the
terrain was rocky and mountainous. A total of five transect lines were set
out (Figure 8), with a total transect length of 17.3 km (transect lengths
varied from 2.4 km to 4.3 km).
49
e1
e2
d1
c1
d2
b1
a1
c2
b2
a2
Figure 8:
Census transects walked – all transects were walked from
east to west i.e. a1 to a2, b1 to b2, c1 to c2 etc. to prevent the
suns glare from distorting visibility.
Census transects are
depicted in green with roads in red.
Transects ran from east to west and were walked as such to prevent the
suns glare from distorting visibility. Transects were walked bi-monthly for 5
months as per recommendations (Barrett, pers. comm., 2003; Henzi, pers.
comm., 2003).
Transects were selected using stratified random sampling techniques and
covered most of the potential habitats except mountain tops which were
excluded due to their precipitous nature.
50
• Conducting the Census
During the census the observer moved along a transect line and stopped
frequently (every five minutes) to listen and scan the surrounding area. A
walking pace of approximately 2-3 km/h was maintained with the use of a
GPS.
Distances paced and direction travelled were calculated and maintained by
pre-plotting transects on a map of the area and using a GPS to pace from
starting to ending points in as straight a line as possible. Each transects
was walked alone.
The following general information was collected during the census:
̇
̇
̇
̇
Start and end GPS locations.
Date and time.
Weather conditions.
Observer name.
Whenever an animal was encountered, two to ten minutes was spent
observing it, depending on the species and its behaviour. The observer
remained on the census route and did not follow the animal or group. For
each encounter the following information was recorded:
̇
̇
̇
̇
̇
Time encounter started.
Species encountered.
Animal to observer distance: distance from observer’s position to
animal when first detected – also called sighting distance.
Animal to transect distance: shortest perpendicular distance from
the animal to the transect line.
Initial animal height (m).
51
̇
̇
̇
̇
̇
̇
̇
̇
̇
Initial animal activity (of first animal detected): resting, moving,
foraging, socializing or other.
Number of animals counted.
Estimated group size.
Mode of detection: visual moving, visual stationary, vocalization or
sound while traveling through the bush.
Age class: adult, sub-adult, juvenile, neonate.
Sex: male, female or unknown.
Vocalizations.
Time encounter ended.
Comments.
Census
transects
starting
and
ending
GPS
co-ordinates
predetermined and setup prior to starting with the census.
were
On census
days, transects were walked from east to west (Figure 8). A GPS was
used to walk along transects and the starting and ending co-ordinates were
captured into the GPS. The GOTO function was then used to go from the
starting location to the end location in as straight a line as possible.
Starting and ending GPS co-ordinates with mean distances of each
transect were recorded and are reflected in Table 3 below.
52
Table 3: Census transects for Blydeberg with starting co-ordinates,
ending co-ordinates and length of transects.
TRANSECT
a1 to a2
b1 to b2
c1 to c2
d1 to d2
e1 to e2
START
END
DISTANCE
CO-ORDINATE
CO-ORDINATE
(km)
30.780561
30.752140
-24.432018
-24.444224
30.780437
30.753006
-24.429663
-24.439143
30.780623
30.755174
-24.427308
-24.434000
30.779509
30.759384
-24.424706
-24.428300
30.780314
30.763100
-24.422228
-24.422537
Total
± 3.2
±3
± 2.7
± 2.1
± 1.7
± 12.7
Transect lines shown in Figure 8 are an overlay of the roads and transects
for orientation purposes. The mean or central lines of all census transects
walked are shown as each time a particular transect was done it was
impossible to do the entire transect exactly along a previous route.
Density calculations were not performed as the area was too small to
justify such, however from the census data obtained a table of the main
species occurring in the area with average numbers was generated, known
group counts and separate sightings have been included (Table 4).
Average number of animals was calculated by summing the number of
animals counted for each species and dividing such by the number of
times they were seen, the same was done for estimated group size – total
animals counted and total estimated group size were added together and
divided by two.
53
Table 4: Census
data
reflecting
species
occurring
on
Blydeberg
Conservancy.
Species
Average
Highest Animal
Tot Numbers
Number Of
Count
From Known
Animals
(Census)
Group Counts
(Census)
Aardvark
1
1
1
10
16
25 (16+9)*
9
14
15
1
1
2
4
10
10
3
3
5
1
1
1
2
3
4
5
30
30
0
0
2
1
1
1
(Orycteropus afer)
Baboon (Papio
ursinus)
Banded Mongoose
(Mungos mungo)
Common Duiker
(Sylvicapra
grimmia)
Blue Wildebeest
(Connochaetes
taurinus)
Bushbuck
(Tragelaphus
scriptus)
Caracal (Felis
caracal)
Giraffe (Giraffa
camelopardalis)
Impala (Aepyceros
melampus)
Porcupine (Hystrix
africaeaustralis)
Slender Mongoose
(Gelerella
sanguinea)
54
Large Spotted
0
0
1
0
0
3
14
28
52 (33+11+8)**
2
5
5
1
1
2
Genet (Genetta
tigrina)
Thick-tailed
bushbaby
(Otolemur
crassicaudatus)
Vervet
(Chlorocebus
aethiops)
Warthog
(Phacochoerus
aethiopicus)
Waterbuck (Kobus
ellipsiprymnus)
* Two known troops, ±16 for the troop at Torchwood and ±9 for the troop at the
gate – some of the latter troop’s animals were injured i.e. broken limbs, limping
etc.
** Three known troops, the study troop were 33, Dunstable troop ±11 and a small
troop at the entrance gate of ±8.
55
REFERENCES
ALTMANN, J.
1974.
Observational study of behaviour: sampling methods.
Behaviour, 49: 227-267.
ARNOLD, T.H. & DE WET, B.C. 1993. Plants of Southern Africa: Names and
distribution. Memoirs of the botanical Survey of South Africa, 62: 1-825.
BARBOUR, M.G., BURK, J.H. & PITTS, W.D. 1987. Terrestrial Plant Ecology. 2nd
ed. Massachusetts: The Benjamin/Cummings Publishing Company, Inc.
BARRETT, LOUISE. 2003. Personal Communication.
Doctor in Primatology.
University of Liverpool.
BEZUIDENHOUT, H. 1993. Syntaxonomy and synecology of Western Transvaal
Grasslands. Ph.D. dissertation, University of Pretoria, Pretoria.
BRAUN-BLANQUET, J. 1932. Plant sociology: the study of plant communities.
New York: McGraw-Hill.
BREDENKAMP, G.J. & BEZUIDENHOUT, H. 1995. A proposed procedure for the
analysis of large data sets in the classification of South African Grasslands.
Koedoe, 38(1): 33-39.
BREDENKAMP, G.J., JOUBERT A.F. & BEZUIDENHOUT, H.
1989.
A
reconnaissance survey of the vegetation of the plains in the PotchefstroomFochville-Parys Area. South African Journal of Botany, 55: 199-206.
56
BROWN, L.R.
1997.
A plant ecological and wildlife management plan of the
Borakalalo Nature Reserve, North-west Province.
Ph.D.
dissertation.
University of Pretoria, Pretoria.
BROWN, L.R. & BREDENKAMP, G.J. 1994. The phytosociology of the southern
section of the Borakalalo Nature Reserve, South Africa. Koedoe, 37: 59-72.
BROWN, L.R., BREDENKAMP, G.J. & VAN ROOYEN, N.
1996.
The
phytosociology of the northern section of the Borakalalo Nature Reserve.
Koedoe, 39(1): 9-24.
CILLIERS, S.S.
1998.
Potchefstroom,
Phytosociological studies of urban open spaces in
North
West
Province,
South
Africa.
Ph.D.
thesis,
Potchefstroom University for CHE, Potchefstroom.
COLLINSON, R.F.H. 1985. Selecting Wildlife Census Techniques. Monograph 6.
University of Natal: Institute of Natural Resources.
ECKHARDT, H.C. 1993. A synecological study of the vegetation of the northeastern Orange Free State. M.Sc. thesis. University of Pretoria, Pretoria.
HAGAN, J.E., EASTMAN, J.R. & AUBLE, J. 1998. Cartalinx the spatial data
builder – Users guide. Clark University, Worcester, USA.
HENNEKENS, S.M. 1996. Megatab: a visual editor for phytosociological tables.
Ulft: Giesen.
HENNEKINS, S. 1998. TURBOVEG: Clipper database management software for
storage, selection, and export of vegetation data (relevés). Netherlands.
57
HENZI, S.P.
2003.
Personal Communication.
Professor in Psychology.
University of Central Lancashire.
HILL, M.O. 1979. TWINSPAN: A Fortran program for arranging multivariate data
in an ordered two-way table by classification of individuals and attributes.
New York: Cornell University.
KENT, M. & COKER, P. 1997. Vegetation Description and Ananlysis – A Practical
Approach. New York: John Wiley & Sons.
KOOIJ, M.S., BREDENKAMP, G.J. & THERON, G.K. 1990. Classification of the
vegetation of the B land type in the north-western Orange Free State. South
African Journal of Botany, 56: 309-318.
MUELLER-DOMBOIS, D. & H. ELLENBERG.
1974.
Aims and methods of
vegetation ecology. New York: Wiley & Sons.
WERGER, M.J.A.
1974.
On concepts and techniques applied in the Zurich-
Montpellier method of vegetation survey. Bothalia, 11: 309-323.
WESTHOFF, V. & VAN DER MAAREL, E.
1978.
20. The Braun-Blanquet
approach. In: Classification of plant communities, ed. R.H. Whitakker, pp.
289-399. Junk, The Hague.
WHITTAKER, R.H.
1978.
Direct gradient analysis.
communities, ed. R.H. Whittaker, pp. 7-50.
Netherlands.
58
In: Ordination of plant
Junk, Groningen, The
CHAPTER 5
A vegetation classification and description as a precursor for vervet monkey
(Chlorocebus aethiops) habitat utilisation, food selection and activity
analysis in the Blydeberg Conservancy, Northern Province.
Barrett, A.S.1, Brown, L.R.1, Barrett, L.2,3 and Henzi, S.P.2,4
1. Applied Behavioural Ecology and Ecosystems Research Unit, University of
South Africa
2. Behavioural Ecology Research Group, University of KwaZulu-Natal
3. School of Biological Science, University of Liverpool
4. Department of Psychology, University of Central Lancashire.
The plant communities of the Blydeberg Conservancy were investigated as part
of a research project on the foraging ecology of the vervet monkey (Chlorocebus
aethiops) in mixed lowveld bushveld and sour lowveld bushveld areas. From a
TWINSPAN classification refined by Braun-Blanquet procedures, ten plant
communities which can be placed into four major groups were identified. A
classification and description of these communities, including a vegetation map
are presented. Diagnostic species as well as prominent and less conspicuous
species of tree, shrub, herb and grass strata are outlined. From the ten plant
communities available to the vervet troop only six were utilized as a food source.
Of the six communities utilized, one was utilized throughout the year, and two
only during the dry season. These communities should be managed effectively
to ensure continued availability of food for the vervets.
Keywords: Braun-Blanquet procedures, conservancy, plant communities,
TWINSPAN, phytosociology, vervet monkey.
59
Introduction
The Blydeberg Conservancy constitutes a group of privately owned farms
belonging to individuals with varying interests. Owners have diverse backgrounds
including farming, hunting, research, business and property development.
The
intention of the conservancy was to pool resources and properties to form a large
area containing various game species for tourism ventures and private utilisation.
Not many extensive vegetation studies have been carried out in the Blydeberg
area or surrounds and those that have been done (Van der Schijff, 1963; Van der
Schijff & Schoonraad, 1971), were done once off without any recorded follow ups
to date. Due to the various land use practices occurring within the area and their
long-term effects on ecosystems, as well as for the research project on vervet
monkeys (Chlorocebus aethiops) undertaken in the area (Barrett, 2005), it was
deemed important to undertake a vegetation description and classification of the
Blydeberg Conservancy.
It is widely recognized that the detailed description, identification, classification and
mapping of vegetation forms the basis of sound land-use planning and
management (Van Rooyen et al. 1981; Tueller 1988; Fuls et al. 1992; Fuls 1993;
Bezuidenhout 1996; Brown 1997). The results obtained from such an endeavor
could be used to assist management in making decisions for the conservancy;
whilst simultaneously providing data for the determination of the seasonal foraging
ecology of the vervet monkeys (Chlorocebus aethiops).
The main aim of the
vegetation study was thus to describe and map the plant communities of the study
area within the Blydeberg Conservancy in order to determine the seasonal foraging
ecology of a troop of vervet monkeys (Chlorocebus aethiops) living within the area.
Vegetation assessments are prerequisites to any ecological or habitat related
research, forming a basis to any further studies (Van Rooyen et al. 1981).
60
Vervet monkeys are extremely adaptable opportunistic generalists (similar to
baboons but, less so) that easily move into disturbed areas, including agricultural
areas, lodges and can even be found in specialized habitats such as mangrove
swamps (Oates, 1996; Kingdon, 1997; Fedigan & Fedigan, 1988; Skinner &
Smithers, 1990; Booth, 1979). Vervets are capable of becoming a pest species in
areas where they are forced into close proximity with humans, leading to conflict
and ultimately their wanton demise. The aim of the encompassing study on vervet
foraging ecology hopes to elucidate some of their foraging behavior.
It is
anticipated that results obtained from such a study would assist management in
successfully implementing management plans for vervets as part of their overall
ecological management strategy. Not many detailed ecological studies of vervets
have been undertaken in temperate sub-tropical areas (Struhsaker, 1967;
Harrison, 1983, 1984; Whitten, 1988; Lee & Hauser, 1998; Isbell et al., 1998;
Pruetz & Isbell, 2000). At these low latitudes, overall habitat productivity is high
and seasonal variability is relatively constrained (Caughley & Sinclair, 1994). A
better understanding of vervet ecological flexibility and the factors that might limit
their distribution both broadly and locally is likely to be derived from the
encompassing study and will benefit the overall management of the species. No
related vervet studies have been undertaken locally. A study on baboon resource
utilisation has been done in the adjacent Blyde Canyon Nature Reserve (Marais,
2005).
Study Area
The Blydeberg Conservancy is situated approximately 19 km south of the town of
Hoedspruit in the Northern Province. It is located between longitude 30° 27’ to 25°
56’ E and latitude 24° 23’ to 24° 28’ S. Altitude ranges from 350 m to 800 m above
sea level (Bredenkamp & Van Rooyen, 1998a, 1998b). The study area constitutes
the farms Dunstable (farm number 230) and Jongmanspruit (farm number 234)
(Figure 1).
61
The current size of the Blydeberg Conservancy is 3000 ha with the study area
being 816 ha.
Figure 1:
Location of Blydeberg Conservancy within the Northern Province of
South Africa.
Geology and Topography
The geology of the conservancy ranges from a zone of fine to medium grained
quartzite, gritty in places with pebble layers; basic lava, tuff, agglomerate and shale
in the South; to a zone of light-grey, medium grained biolite gneiss with coarsegrained quartz-feldspar leucosomes; recrystallised in places in the North (Visser,
1989; Walraven, 1989).
An intermediate zone of laminated micaceous and
graphitic shale, locally interlayered with sandy shale, flagstone and quartzite
separates the southern and northern zones (Visser, 1989; Walraven, 1989).
62
Also, according to Visser (1989) and Walraven (1989), intermittently layered along
the south of the northern zone and between such and the intermediate zone is
another less distinct zone of greenish grey intermediate lava, amygdaloidal in
places, interbedded porphyritic layers and layers of shale and quartzite. Visser
(1989) and Walraven (1989), state that the southern, intermediate and the less
distinct zone between the northern and intermediate zones are rocks of volcanic
and sedimentary origin dating back to the Vaalian Quaternary. The southern zone
originates from the Black Reef formation of the Transvaal Sequence; the
intermediate zone originates from the Selati Formation of the undifferentiated
upper part of the Wolkberg Group and the less distinct zone between the northern
and intermediate zones originates from the Abel Erasmus formation of the
undifferentiated lower part of the Wolkberg Group (Visser, 1989; Walraven, 1989;
Buckle, 1992). The northern zone is rock of intrusive origin, dating back to the
Swazian Quaternary (Visser, 1989; Walraven, 1989; Buckle, 1992).
The topography of the study area is mostly mountainous with steep to moderately
steep slopes gradually tapering off to a relatively flat mountain plateau. In the
southern section of the area the Drakensberg Mountains form the southern
boundary of the study area and have very steep slopes and rock faces that are
almost impossible to traverse. The northern section of the study area is less steep
and the terrain is relatively flat. The geology is a combination of volcanic and
sedimentary rocks in the south, and intrusive rocks in the north.
Land Types
Four land types, namely Fa, Fb, Ib and Ic, occur in the study area as indicated in
the terrain form sketch (Figure 2). According to Land Type Survey Staff (1989), “A
land type denotes an area that can be shown at 1:250 000 scale and displays a
marked degree of uniformity with respect to terrain form, soil pattern and climate”.
63
A close association between the major plant communities and the different land
types has been observed in other studies (Kooij et al., 1990; Bezuidenhout, 1993;
Eckhardt, 1993; Brown, 1997).
a)
b)
c)
d)
Figure 2:
Terrain form sketches indicating the various land types of the study
area. a) is land type Fa, b) is land type Fb, c) is land type Ib, and d)
is land type Ic. Within the land type sketches, 1=Crest, 2=Scarp,
3=Mid slope, 4=Foot slope, 5=Valley bottom.
64
The F land type refers to pedologically young landscapes that are not
predominantly rock and alluvial or aeolian, in which the main soil forming
processes have been rock weathering (Land Type Survey Staff, 1989).
The
formation of orthic topsoil horizons and clay illuviation have typically given rise to
lithocutanic horizons (Land Type Survey Staff, 1989). Dominant soil forms are
Glenrosa and Mispah, with Oakleaf present in upland areas (Soil Classification
Working Group, 1991).
In the Fa land type lime in the soil is not commonly encountered and is rare or
absent throughout the landscape. Soils are mostly medium sandy loam to sandy
clay loam (Soil Classification Working Group, 1991). Soils are shallower than 400
mm.
The geology consists of shale, quartzite, conglomerate and basalt of the Wolkberg
group, Transvaal Sequence (Land Type Survey Staff, 1989).
In the Fb land type, lime in the soil is rare or absent in upland areas but, generally,
lime is present in low-lying areas. Soils are mostly medium to coarse sand to
loamy sand (Soil Classification Working Group, 1991). Soils are shallower than
1200 mm.
The geology consists of unnamed potassic granite and granodiorite (Land Type
Survey Staff, 1989).
The I land type refers to miscellaneous land classes (Land Type Survey Staff,
1989). The land type Ib indicates land types with exposed rock (country rock,
stones or boulders), which covers 60-80 % of the area. Soils are mostly medium
sandy clay loam to sandy clay (Soil Classification Working Group, 1991). Soils are
shallower than 900 mm.
65
The geology consists of quartzite, conglomerate, shale and basalt of the Black
Reef Formation, Transvaal Sequence (Land Type Survey Staff, 1989).
The land type Ic refers to land types with exposed rock (country rock, stones or
boulders) covering more than 80 % of the area. Soils are mostly fine to medium
sandy loam to sandy clay loam (Soil Classification Working Group, 1991). Soils
are shallower than 300 mm.
The geology consists of shale, quartzite, conglomerate and basalt of the Wolkberg
Group, Transvaal Sequence (Land Type Survey Staff, 1989).
Vegetation
The area is rather patchy and vegetation varies from relatively open bushveld with
long grass species on undulating hills and slopes, through dense shrub and scrub
in dry ravines and dongas, to patches of semi-montane forest in sheltered kloofs.
The area can be classified as intermediate between Mixed Lowveld Bushveld veld type 19 (Bredenkamp & Van Rooyen, 1998a) and Sour Lowveld Bushveld veld type 21 (Bredenkamp & Van Rooyen, 1998b).
Climate
The average annual rainfall for the study area, as measured by a weather station
situated on the Jongmanspruit farm (farm number 234) for the period 05/1999 to
04/2004 was 561 mm, with a high of 953 mm and a low of 255 mm recorded in
2000 and 2002 respectively. For the period 05/1999 to 04/2004, average monthly
rainfall varied from 0.7 mm during the dry winter season (May to October) to 106
mm in the wet summer season (November to April) (Figure 3).
66
200
180
160
140
120
100
80
60
40
20
0
Temperature ( o C)
25
20
15
10
5
0
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Rainfall (mm)
30
Apr
Month
Figure 3:
Avg Temp - Hoedspruit 99-04
Avg Temp - Blydeberg 99-04
Avg Rainfall - Hoedspruit 99-04
Avg Rainfall - Blydegerg 99-04
Average monthly rainfall and temperatures for the Blydeberg
Conservancy and Hoedspruit from 05/1999 to 04/2004.
For the larger Hoedspruit region, average annual rainfall for the period 05/1999 to
04/2004 was 900 mm with a high of 1463 mm and a low of 629 mm recorded in
2000 and 2002 respectively. For the period 05/1999 to 04/2004, average monthly
rainfall varied from 2 mm during the dry winter season (May to October) to 189 mm
in the wet summer season (November to April) (Figure 3).
Rainfall recorded for the study area is less than that of the larger Hoedspruit region
due to the study areas location on the foothills of the Drakensberg Mountains along
the great escarpment. The mountains form a barrier leading to a rain shadow
which could be responsible for less rainfall in the study area.
However, the
mountains do function as an important catchment for the study area and are the
source of several small mountain streams (Van Zyl, 2003). Locally thunderstorms
and fog are the main sources of precipitation for the study area.
67
Average annual temperature for the study area for the period 05/1999 to 04/2004
was 22oC, with mean temperatures varying from 17oC during the dry winter season
to 26oC in the wet summer season (Figure 3). A minimum temperature of 3oC and
a maximum of 42oC were recorded in the 05/2003 to 04/2004 period.
Average annual temperature for larger Hoedspruit region for the period 05/1999 to
04/2004 was 17oC, with mean temperatures varying from 11oC during the dry
winter season to 23oC in the wet summer season (Figure 3).
A minimum
temperature of 11oC and a maximum of 23oC were recorded in the 05/2003 to
04/2004 period.
Temperatures for the study area are higher than those for the larger Hoedspruit
region due to the study area lying along the north facing foot slopes of the
Drakensberg Mountains along the great escarpment. The study area has more
direct exposure to sunlight and is more sheltered from southerly winds than the
surrounding areas (Tyson & Preston-Whyte, 2000).
Methods
Using a 1:10 000 digitized ortho photo for the Blydeberg area, the study area was
stratified into physiognomic-physiographic units (Barbour et al., 1987; Kent &
Coker, 1997). A total of 49 sample plots were located in a randomly stratified
manner within these units to ensure that all variations in the vegetation were
considered and sampled. Plot sizes were fixed at 400 m2 (Barbour et al., 1987;
Brown & Bredenkamp, 1994; Brown, 1997).
In each sample plot all species were recorded and cover abundance was assessed
using the Braun-Blanquet cover abundance scale (Mueller-Dombois & Ellenberg,
1974; Barbour et al., 1987).
68
Fieldwork was undertaken during April, May, and June 2003 and in January 2004.
In the light of taxon names constantly changing, this publication conforms to those
of Arnold & De Wet (1993).
Environmental data collected included aspect, estimates of slope, percentage
rockiness and percentage erosion.
Floristic Data were analyzed according to
Braun-Blanquet procedures using the TURBOVEG suite (Hennekens, 1998), which
includes the Two-way indicator species analysis multivariate classification
technique (TWINSPAN) (Hill, 1979) for deriving an initial approximation of the main
plant communities.
This numerical classification technique is regarded as a
successful approach to vegetation classification by various phytosociologists
(Brown & Bredenkamp, 1994; Bredenkamp & Bezuidenhout, 1995; Brown et al.,
1996; Cilliers, 1998). The visual editor MEGATAB (Hennekens, 1996) was used to
generate a phytosociological table. Further refinement of the classification was
undertaken through the application of Braun-Blanquet procedures (Barbour et al.
1987; Bredenkamp et al. 1989; Kooij et al. 1990; Bezuidenhout 1993; Eckhardt
1993; Brown & Bredenkamp 1994; Kent & Coker 1997).
Using the final
phytosociological table and habitat information collected during sampling in the
field, different plant communities were identified, described and ecologically
interpreted.
Erosion was estimated within the following classes (Matthee & Van Schalkwayk,
1984):
Class 1
Slight.
Class 2
Moderate loss of topsoil with slight soil cutting by run-off
channels or gullies.
Class 3
Severe loss of topsoil with marked soil cutting by run-off
channels or gullies.
Class 4
Total loss of topsoil and exposure of subsoil or deep
intricate soil cutting by gullies.
69
Slope was estimated within the following categories:
Level
0-30
Gentle
3-80
Moderate
8-160
Steep
16-260
Very steep
26-450
Results
Classification
The analysis resulted in the identification of the following ten plant communities
(Figure 4), which may be grouped into four major community types (Table 1):
1. Eragrostis lehmanniana-Grewia flava Shrubland.
1.1 Heteropogon contortus-Grewia flava Shrubland.
1.2 Ziziphus mucronata-Grewia flava Shrubland.
2. Bridelia mollis-Acacia nigrescens Woodland.
2.1 Berchemia zeyheri-Acacia nigrescens Woodland.
2.2 Combretum imberbe-Acacia nigrescens Woodland.
3. Acacia nigrescens-Combretum apiculatum Woodland.
4. Gymnosporia glaucophylla-Panicum maximum Woodland.
4.1 Balanites maughamii-Panicum maximum Woodland.
4.2 Sclerocarya birrea-Panicum maximum Woodland.
4.3 Combretum zeyheri-Panicum maximum Woodland.
4.4 Asparagus setaceus-Philenoptera violacea Woodland.
4.4.1 Pappea capensis Variant.
4.4.2 Diospyros mespiliformis Variant.
70
Figure 4:
Vegetation map of the study area within the Blydeberg Conservancy.
Map depicts the various plant communities, sub-communities and
variants.
71
Description of plant communities
The study area is mostly open woodland with a depleted herbaceous layer due to a
history of overgrazing and irregular agricultural practices leading to low plant
species diversity. The vegetation comprises a mixture of dense montane forest in
kloofs, open tree savanna sour bushveld on northern and western slopes, high
mountain sour grass veld and dense riverine thickets along drainage lines and
streams. There is a strong presence of the shrub species Grewia flava and Grewia
flavescens throughout the study area.
The general vegetation of the study area is characterized by the presence of
species from species groups O, P and Q occurring in communities 1, 2, 3 and 4;
and with species from species group N found mostly in communities 1, 2 and 3.
For all species groups refer to Table 1.
Prominent species include the shrubs Grewia flavescens, Grewia flava (species
group Q), Dichrostachys cinerea (species group P) and the grass Elionurus
muticus (species group Q) which occur in all communities, and the trees
Combretum apiculatum and Ziziphus mucronata (species group P) which occur in
most communities with the exception of sub-community 4.4.2.
The tree
Sclerocarya birrea (species group O) is prominent in most communities except
sub-community 4.4. The tree Acacia nigrescens (species group O) is dominant in
communities 1, 2, 3 and sub-community 4.1 (Table 1).
Table 2 depicts additional plant species recoded for Blydeberg but not significant
enough to be reflected in table 1. The species names and the communities they
occur in are presented.
76
Table 2:
Table of less prevalent plant species occurring at Blydeberg and not
represented in Table 1.
Community
Species Name
Community
Species Name
Number
Number
Acacia burkei
1.1, 2.1
Melinis repens
2.2
Acacia galpinii
1.1
Nuxia oppositifolia
4.4
Acacia tortilis
1.1
Olea europaea
2.1, 4.1
Aloe dyeri
1.2
Opuntia ficus-indica
2.2
Aloe marlothii
4.1, 4.2
Ozoroa paniculosa
1.2, 2.2
Asparagus cooperi
1.1, 3
Ozoroa sphaerocarpa
4.2
Bacchar adoensi v. kot
2.1
Pavonia columella
4.2, 4.4
Boscia albitrunca
1.2, 2.2
Plectroniella armata
2.2
Canthium ciliatum
2.1
Rauvolfia caffra
4.3
Capparis tormentosa
4.3
Rhigozum obovatum
1.1
Celtis africana
4.4
Rhus dentata
4.4
Chloris virgata
1.1
Rhus tumulicola
4.3
Cussonia spicata
1.1
Schotia brachypetala
4.1
Diheteropogon filifolius
1.2
Scolopia zeyheri
4.4
Eragrostis rigidior
4.4
Spirostachys africana
4.4
Eragrostis superba
2.1
Strelitzia nicolai
1.2
Eustachys paspaloides
4.2
Strophanthus gerrardii
4.2, 4.3
Ficus sycomorus
4.3
Strophanthus speciousus
4.3
Garcinia livingstonei
4.3
Tagetes minuta
1.1, 1.2
Hippocratea crenata
4.3
Terminalia sericea
1.1, 2.1
Hyparrhenia hirta
1.2
Trichilia emetica
4.4
Hypoxis hemerocallidea
1.1
Vernonia adoensis
2.1
Leucosidea sericea
1.2
Wachendorfia parviflor
4.2
Maerua angolensis
4.1
Xanthium spinosum
2.1
Markhamia zanzibarica
4.2
77
1. Eragrostis lehmanniana-Grewia flava Shrubland.
This shrubland plant community covers approximately 24 % of the study area (193
ha) and consists of flat rocky terrain with the vegetation in various stages of
degradation (Figure 4). Soils are sandy, gravely and relatively well drained. Rock
cover for this community varies between 20-45 % and erosion is estimated at 15
%.
Species belonging to species group A are diagnostic for this community and
include the trees Acacia exuvialis, Sterculia rogersii, the grasses Eragrostis
lehmanniana, Aristida congesta, A. stipitata, and the forbs Sida cordifolia and
Corchorus kirkii.
Vegetation is dominated by the trees Acacia nigrescens, Sclerocarya birrea
(species group O), Ziziphus mucronata and Combretum apiculatum (species group
P), while the shrubs Dichrostachys cinerea (species group P), Grewia flava and
Grewia flavescens (species group Q) are also prominent. The grass layer is not
well developed and includes Elionurus muticus (species group Q), Panicum
maximum (species group F) and Eragrostis lehmanniana (species group A).
Portions of this community were previously used for cultivation purposes and are in
various stages of secondary succession as can be seen from the large number of
different species that are prominent within this community.
This community is
divided into two sub communities.
Although they are delineated on the vegetation map, small sections of sub
community 1.1 form a mosaic distribution pattern within sub community 2.2 and
could therefore not be mapped.
78
1.1
Heteropogon contortus-Grewia flava Shrubland.
The Heteropogon contortus-Grewia flava sub-community is situated in three small
areas in the northwest and central sections of the study site (Figure 4). This subcommunity covers 3 % of the study area (20 ha) and 10 % of community 1, and
occurs on what appears to be more disturbed sites or pockets. The areas are
relatively rocky (20 %) and fairly open. Erosion is estimated at 15 % with gentle
slopes. Soils are mostly sandy and gravely.
The grasses Heteropogon contortus, Digitaria eriantha and Pogonarthria squarrosa
(species group B) are diagnostic for this sub-community.
The vegetation is dominated locally by the trees Combretum apiculatum (species
group P), Acacia nigrescens and Sclerocarya birrea (species group O), together
with the shrubs Dichrostachys cinerea (species group P), and Grewia flavescens
(species group Q). The herbaceous layer is not well developed and includes the
grasses
Eragrostis
lehmanniana
(species
group
A),
Digitaria
eriantha,
Heteropogon contortus (species group B) and Panicum maximum (species group
F).
The average number of plants per 400 m2 in this sub-community is 17. The tree
layer has a 10-60 % cover with an average of 37 %, the shrub layer has a 10-70 %
cover with an average of 29 %, the herb layer has a 0-5 % cover with an average
of 2 %, and the grass layer has a 1-70 % cover with an average of 26 %.
The shrub Dichrostachys cinerea has the highest density of 5 333 ind/ha followed
by the tree Acacia nigrescens with 2 583 ind/ha and the shrub Acacia karroo with 2
167 ind/ha.
79
1.2
Ziziphus mucronata-Grewia flava Shrubland.
This sub-community comprises two separate sections. One section is located on
the northern boundary of the study area while the other is located on the eastern
boundary extending towards the southern boundary in a narrow strip, isolating subcommunity 2.1 from the rest of the study area (Figure 4). This sub-community
covers 21 % of the study area (173 ha) and 90 % of community 1, being flat and
relatively open with signs of prior mismanagement in the form of bush
encroachment and several stands of same sized and aged trees occurring within
this sub-community. The areas are quite rocky (45 %). Erosion is estimated at 15
% with gentle slopes. Soils are mostly sandy, gravely and relatively deep.
The tree Commiphora africana, the shrub Balanites pedicellaris, the herbs Cyclopia
capensis and Bidens pilosa, the grass Anthephora pubescens, and the forb
Solanum panduriforme (species group C) are diagnostic species for this subcommunity.
The vegetation is dominated by the trees Acacia nigrescens (species group O),
Ziziphus mucronata, Combretum apiculatum (species group P), and the shrub
Grewia flava (species group Q). The tree Sclerocarya birrea (species group O), is
also very prominent within this sub-community. The herbaceous layer comprises
the grasses Elionurus muticus (species group Q) and Eragrostis lehmanniana
(species group A) that are locally prominent. The pioneer forbs Bidens pilosa and
Solanum panduriforme (species group C) are also present.
The average number of plant species per 400 m2 in this sub-community is 15. The
tree layer has a 5-80 % cover with an average of 46 %, the shrub layer has a 5-90
% cover with an average of 42 %, the herb layer has a 0-80 % cover with an
average of 17 %, and the grass layer has a 1-70 % cover with an average of 17 %.
80
The tree Acacia exuvialis has the highest density of 6 000 ind/ha followed closely
by the shrub Grewia flava with 5 222 ind/ha, and the tree Ziziphus mucronata with
2 667 ind/ha.
2. Bridelia mollis-Acacia nigrescens Woodland.
The Bridelia mollis-Acacia nigrescens woodland comprises the largest proportion
of the study area and covers 51% (415 ha) of the conservancy (Figure 4). Soils
are mostly sandy and well drained with a non-perennial mountain stream passing
through the centre of this community. Rock cover and erosion estimates for this
community varies between 25-35 % and 10-15 % respectively.
Species belonging to species group D are diagnostic for this community and
include the trees Ficus stuhlmannii, Combretum imberbe and Bridelia mollis.
The vegetation is dominated by the trees Acacia nigrescens (species group O),
Combretum apiculatum (species group P) and Acacia karroo shrubs (species
group N).
The trees Bridelia mollis (species group D) and Sclerocarya birrea
(species group O) are locally prominent. Other species also present include the
shrubs Dichrostachys cinerea (species group P), Grewia flava, Grewia flavescens
(species group Q), and the grass Elionurus muticus (species group Q). The grass
species Anthephora pubescens (species group C) occurs sparsely in the
community, being locally dominant.
Within this community there are signs of previous overgrazing with old kraals,
dipping structures and various old farming implements found throughout the area.
This community consists of two sub-communities.
81
2.1
Berchemia zeyheri-Acacia nigrescens Woodland.
The Berchemia zeyheri-Acacia nigrescens sub-community is located in two large
areas in the southern and southeastern sections of the study area (Figure 4). This
sub-community is relatively large covering 28 % of the study area (226 ha) and 54
% of community 2, and occurs in areas where there are signs of historical
disturbance, particularly overgrazing with some relics of agricultural farming found
within the area. The areas are flat with gentle slopes and sandy soils. Intermittent
rocks are scattered throughout (35 % rockiness).
There is slight evidence of
erosion in the form of small furrows at places (erosion estimated at 10 %).
The trees Berchemia zeyheri, Commiphora mollis, Lannea discolor, the shrubs
Mundulea sericea, Euclea divinorum, and the grasses Imperata cylindrica and
Brachiaria brizantha (species group E) are diagnostic for this sub-community.
The woody layer comprises a mixture of species with the vegetation dominated by
the trees Acacia nigrescens (species group O), Combretum apiculatum (species
group P), and Acacia karroo shrubs (species group N).
The trees Berchemia
zeyheri (species group E), Sclerocarya birrea (species group O) and Ziziphus
mucronata (species group P) are locally prominent.
The shrubs Grewia flava,
Grewia flavescens (species group Q), Gymnosporia glaucophylla (species group
G), the grass Elionurus muticus (species group Q) and the forb Lobelia species
(species group N) are also present.
The average number of plants per 400 m2 in this sub-community is 16. The tree
layer has a 10-80 % cover with an average of 46 %, the shrub layer has a 5-80 %
cover with an average of 34 %, the herb layer has a 1-30 % cover with an average
of 8 %, and the grass layer has a 1-60 % cover with an average of 20 %. The
shrub Acacia karroo has the highest density of 5 615 ind/ha followed by the trees
Acacia nigrescens with 3 962 ind/ha and Combretum apiculatum with 3 308 ind/ha.
82
2.2
Combretum imberbe-Acacia nigrescens Woodland.
This sub-community is located centrally and towards the western boundary of the
study area, east of community 3 that forms part of the western boundary of the
study area (Figure 4). This woodland is relatively large covering 23% of the study
area (189 ha) and 46 % of community 2, and is mainly flat and open with signs of
mismanagement in the form of previous overgrazing. Rockiness is estimated at 25
% with most rocks occurring adjacent to a dry river bed. Erosion is estimated at 15
%. The area has a gentle slope with soils being predominantly sandy and well
drained.
Characteristic of this sub-community is the absence of species from species group
E. The trees Peltophorum africanum (species group G), Combretum apiculatum,
Ziziphus mucronata (species group P) and the shrub Dichrostachys cinerea
(species group P) dominate the vegetation. Other species also present are the
tree Bridelia mollis (species group D), the shrub Corchorus kirkii (species group A),
and the grass Elionurus muticus (species group Q) being locally prominent.
The average number of plants per 400 m2 in this sub-community is 18. The tree
layer has a 30-90 % cover with an average of 60 %, the shrub layer has a 5-40 %
cover with an average of 18 %, the herb layer has 0 % cover, and the grass layer
has a 1-40 % cover with an average of 19 %. The shrub Dichrostachys cineria has
the highest density of 5 500 ind/ha, with the tree Combretum apiculatum having 2
500 ind/ha and the shrub Grewia flavescens having 1 667 ind/ha.
83
3.
Acacia nigrescens-Combretum apiculatum Woodland.
This woodland community forms part of the western boundary of the study area
covering approximately 6 % (48 ha) of such (Figure 4). Slope is moderate with
shallow soils as most of the community is on a rocky protrusion. Average erosion
for this community is estimated at 10 %, with average rockiness estimated at 15 %.
The Acacia nigrescens-Combretum apiculatum Woodland is characterized by the
absence of any diagnostic species. Also characteristic of this woodland is the
presence of species from species group F and the absence of species from
species groups G to M.
Vegetation is dominated by the trees Combretum
apiculatum (species group P), Acacia nigrescens, Sclerocarya birrea (species
group O), the shrub Grewia flava (species group Q), and the grass Elionurus
muticus (species group Q).
Characteristic of this community is the absence of the shrubs Dichrostachys
cinerea (species group P) that are present in almost all the other communities of
the study area.
Acacia karroo shrubs (species group N) are present.
This
community has a more developed herbaceous layer with the increaser 2 grass
Eragrostis lehmanniana (species group A) and the decreaser grass Panicum
maximum (species group F) present throughout.
There are signs of previous overgrazing by cattle in this community, with several
old farm implements scattered throughout the community. The dominance of the
increaser 3 grass Elionurus muticus (species group Q) is indicative of the degraded
condition of the herbaceous layer. However, the presence of the grasses Panicum
maximum (species group F) and Eragrostis lehmanniana (species group A) is
indicative that this community is recovering and in a secondary successional
phase.
84
The average number of plants per 400 m2 in this community is 13. The tree layer
has an average estimated cover of 32 %, the shrub layer has an average
estimated cover of 18 %, the herb layer has an average estimated cover of 1 %,
and the grass layer has an average estimated cover of 33 %. The shrub Grewia
flava has a density of 4833 ind/ha, the tree Combretum apiculatum has 4000
ind/ha and the shrub Acacia karroo has 3333 ind/ha.
4.
Gymnosporia glaucophylla-Panicum maximum Woodland.
This woodland plant community covers approximately 20 % of the study area (160
ha) and is mostly mountainous (Figure 4). Soils are predominantly sandy and
relatively well drained. Rock cover for this community varies between 10-50 % and
erosion is estimated at 10 %.
Species belonging to species groups F and G are diagnostic for this community
and include the trees Peltophorum africanum and Rhus leptodictya, the shrub
Gymnosporia glaucophylla, and the grass Panicum maximum.
The vegetation is dominated by the shrubs Grewia flavescens and Grewia flava
(species group Q), while the grass Elionurus muticus (species group Q) is also
prominent. The trees Combretum apiculatum and Ziziphus mucronata (species
group P), and the shrub Dichrostachys cinerea (species group P) are also
dominant throughout, except in the Diospyros mespiliformis Variant.
There are many signs of animal activity throughout this community, mainly game
tracks, middens and foraging evidence. There are also signs of previous cattle
grazing. A few roads pass through the community and a few small dwellings are
present. This community consists of four sub-communities and two variants.
85
4.1
Balanites maughamii-Panicum maximum Woodland.
This sub-community is located in the south western section of the study area and
consists of two separate areas split by the Pappea capensis Variant (Figure 4).
This sub-community covers 5 % of the study area (43 ha) and 27 % of community
4, and is found on the relatively steep, predominantly north facing foot slopes of the
Drakensberg Mountain Range constituting the southern boundary of the study
area. There are signs of previous cattle grazing in the low lying areas. The areas
are relatively rocky (30 %). Erosion is estimated at 10 % with a moderate to steep
slope. Soils are mostly sandy.
The trees Combretum erythrophyllum and Balanites maughamii, the shrub
Gossypium herbaceum, and the perennial herb Argyrolobium velutinum (species
group H) are diagnostic for this community.
The woody layer comprises a mixture of species with the vegetation dominated by
the trees Combretum apiculatum, Ziziphus mucronata (species group P) and
Sclerocarya birrea (species group O), the shrubs Dichrostachys cinerea (species
group P) and Grewia flavescens (species group Q), and the grass Elionurus
muticus (species group Q). The tree Acacia nigrescens (species group O) and the
shrub Grewia flava (species group Q) are also present.
The average number of plants per 400 m2 in this sub-community is 15. The tree
layer has a 40-80 % cover with an average of 55 %, the shrub layer has a 20-50 %
cover with an average of 30 %, the herb layer has 1 % cover, and the grass layer
has a 40-60 % cover with an average of 49 %. The shrub Dichrostachys cineria
has the highest density of 7995 ind/ha followed by the shrubs Grewia flavescens
with 5750 ind/ha and Grewia flava with 4125 ind/ha.
86
4.2
Sclerocarya birrea-Panicum maximum Woodland.
This is a small sub-community occupying the south western corner of the study
area (Figure 4). This woodland covers 1 % of the study area (5 ha) and 3 % of
community 4. The area is steep and has a large cliff like rock face forming part of
its eastern boundary. There are many signs of wild animal activity and several
animal tracks traverse this sub-community. Rockiness and erosion are estimated
at 30 % and 10 % respectively. Soils are predominantly sandy and shallow.
The grass Cymbopogon excavatus and the herbaceous shrublet Pelargonium sp.
(species group I) are diagnostic for this sub-community.
The vegetation is dominated by the trees Sclerocarya birrea (species group O) and
Combretum apiculatum (species group P). The shrub Grewia flavescens (species
group Q) and the grass Elionurus muticus (species group Q) are also very
prominent within this sub-community. The tree Acacia exuvialis (species group A)
is also present.
The average number of plants per 400 m2 in this sub-community is 15. The tree
layer has a 30-80 % cover with an average of 47 %, the shrub layer has a 5-80 %
cover with an average of 42 %, the herb layer has 0-1 % cover with an average of
1 %, and the grass layer has a 40-90 % cover with an average of 70 %.
The tree Combretum apiculatum has the highest density of 5000 ind/ha, followed
by the tree Sclerocarya birrea that has 2333 ind/ha and the shrub Grewia
flavescens that has 2320 ind/ha.
87
4.3
Combretum zeyheri-Panicum maximum Woodland.
This sub-community is found in the south western section of the study area (Figure
4). This woodland covers 6 % of the study area (51 ha) and 32 % of community 4.
The area is moderate to steep in the south, gradually becoming moderate towards
the north. A few small dwellings are found within this sub-community. There are
many signs of wild animal activity and some previous signs of human agricultural
disturbance in the form of old farm implements lying in the veld. Small unused
man made dams and open areas with stands of similar size and aged
Dichrostachys cinerea shrubs occur throughout, indicating overgrazing by cattle.
Rockiness and erosion are estimated at 45 % and 10 % respectively. Soils are
sandy and shallow in the south, becoming deeper towards the north.
The trees Acacia caffra and Combretum zeyheri, and the shrub Ptaeroxylon
obliquum (species group J) are diagnostic for this sub-community.
The vegetation is dominated by the trees Sclerocarya birrea (species group O) and
Combretum apiculatum (species group P), and the shrub Grewia flavescens
(species group Q). The shrub Dichrostachys cineria (species group P) and the
grass Elionurus muticus (species group Q) are also prominent within this subcommunity. There is also a strong presence of the tree Bridelia mollis (species
group D).
The average number of plants per 400 m2 in this sub-community is 17. The tree
layer has a 70-80 % cover with an average of 73 %, the shrub layer has a 15-70 %
cover with an average of 35 %, the herb layer has a 0-1 % cover with an average
of 1 %, and the grass layer has a 1-80 % cover with an average of 29 %. The tree
Combretum apiculatum has the highest density of 4500 ind/ha, the shrub
Dichrostachys cineria has 3833 ind/ha and the shrub Grewia flavescens has 3500
ind/ha.
88
4.4
Asparagus setaceus-Philenoptera violacea Woodland.
This woodland sub-community consists of two variants, the Pappea capensis
Variant located in the south western section of the study area, and the Diospyros
mespiliformis Variant located in the north eastern section (Figure 4). This subcommunity covers approximately 8 % of the study area (61 ha) and 38 % of
community 4. The terrain ranges from steep (the Pappea capensis Variant) to
gentle (the Diospyros mespiliformis Variant). Rockiness for this sub-community
varies between 10-50% and erosion is estimated at 10 %. Soils are predominantly
sandy and well drained.
The trees Philenoptera violacea, Combretum hereroense and Combretum molle,
the shrub Dovyalis caffra, and the herbs Asparagus setaceus and Tacazzea
apiculata (species group K) are diagnostic for this sub-community.
The vegetation is dominated by the shrub Grewia flavescens (species group Q).
The shrub Grewia flava and the grass Elionurus muticus (species group Q) are
also prominent within this sub-community. There is a strong presence of the tree
Berchemia zeyheri (species group E).
There are signs of previous and current human disturbance in the form of old cattle
dipping structures, old cattle kraals, recent vegetation removal for development, a
few recently constructed log cabins and a new earthen dam.
89
4.4.1
Pappea capensis Variant.
This variant is located on the north facing mid- and foot-slopes of the Drakensberg
Mountains in the south eastern section of the study area and divides the Balanites
maughamii-Panicum maximum Woodland sub-community into an eastern and
western section (Figure 4). This variant covers 1 % of the study area (7 ha) and 11
% of sub-community 4.4, and is found on the moderate to steep mid- and footslopes of the Drakensberg Mountain Range. Signs of human disturbance include
previous cattle dipping structures and kraals. Rockiness is estimated at 50 % and
erosion is estimated at 10 %. Soils are sandy.
The tree Pappea capensis and the shrubs Bolusanthus speciosus, Euclea crispa,
Ehretia rigida and Grewia monticola (species group L) are diagnostic for this
variant.
The vegetation is dominated by the tree Combretum apiculatum (species group P)
and the shrub Grewia flavescens (species group Q). The tree Commiphora mollis
(species group E) and the grass Elionurus muticus (species group Q) are also
prominent in this variant. The trees Ziziphus mucronata (species group P), Ficus
stuhlmannii (species group D) and Berchemia zeyheri (species group E), and the
shrubs Dichrostachys cinerea (species group P), Grewia flava (species group Q)
and Euclea divinorum (species group E) are also present.
The average number of plants per 400 m2 is 22. The tree layer has a 70-90 %
cover with an average of 80 %, the shrub layer has a 15-60 % cover with an
average of 38 %, the herb layer has a 2-5 % cover with an average of 4 %, and the
grass layer has a 20-70 % cover with an average of 45 %. The shrub species
Grewia flavescens has the highest density of 2500 ind/ha, with the tree species
Combretum apiculatum having 1750 ind/ha, and the shrub species Grewia flava
with 1500 ind/ha.
90
4.4.2
Diospyros mespiliformis Variant.
This variant is located in the north eastern section of the study area (Figure 4),
covering 7 % of the study area (54 ha) and 89 % of sub-community 4.4. Slope is
gentle. A dry river bed with several large riverine trees growing adjacent to the
river bed runs through the area.
There are many signs of recent human
disturbance throughout this variant. Several small wooden cabins and an earthen
dam have recently been constructed along the river bed due to the shady and
aesthetic nature of the area. A portion of the variants vegetation has also been
removed for development. Average erosion for this community is estimated at 10
%, with average rockiness also estimated at 10 %. Soils are deep, sandy and well
drained.
Species belonging to species group M are diagnostic for this variant and include
the trees Diospyros mespiliformis, Acacia schweinfurthii and Dombeya rotundifolia,
the shrubs Indigofera arrecta and Morella pilulifera, the herb Asparagus virgatus,
and the liana Dalbergia armata.
The vegetation is dominated by the shrubs Grewia flavescens and Grewia flava
(species group Q).
prominent.
The tree Berchemia zeyheri (species group E) is also
The grass layer is not well developed and includes the grasses
Panicum maximum (species group F) and Elionurus muticus (species group Q).
The average number of plants per 400 m2 is 16. The tree layer has an 80-90 %
cover with an average of 87 %, the shrub layer has a 30-60 % cover with an
average of 40 %, the herb layer has a 2-3 % cover with an average of 2 %, and the
grass layer has a 0-5 % cover with an average of 2 %. The shrub species Grewia
flava has the highest density of 2000 ind/ha, with the tree species Berchemia
zeyheri having 1950 ind/ha, and the tree species Diospyros mespiliformis with
1667 ind/ha.
91
Ordination
Figure 5 depicts community vegetation cover percentages and abiotic parameters
along estimated gradients of slope, erosion and rockiness. There is a general
increase in tree cover from community 1 to community 4, with the exception of
community 3 which occurs on a rocky protrusion with shallow soils which is more
conducive to grasses (Figure 5a). An increase in tree cover along this gradient
could be attributable to declines in estimated erosion and rockiness from
community 1 to community 4, reaching their respective troughs in community 3 due
to the rocky protrusion (Figure 5b).
Shrub and herb cover decrease from
community 1 to community 3, but increase slightly in community 4 (Figure 5a).
This decrease could be related to a trend of increasing tree cover which blocks
sunlight and out competes non-woody vegetation. The tree and shrub cover are
very similar in community 1.
This can be ascribed to the community being
disturbed by previous agricultural practices. As a result large areas that have been
cleared of bush are now being encroached by shrubs while the natural areas are
characterised by large trees. Increases in slope and decreases in erosion and
rockiness (with the exception of community 3 which occurs on a rocky outcrop as
mentioned previously) from community 1 to community 4 (Figure 5b), might also be
partially responsible for increases in shrub cover for community 4.
Grass cover generally increases with increasing slope, decreasing erosion, and
decreasing rockiness from community 1 to community 4 (Figure 5a & 5b), with a
slight exception for community 2 which could be due to previous mismanagement
and overgrazing. As grass cover increases, erosion decreases.
92
80
Percentage Cover
70
60
50
40
30
20
10
0
0
1
2
3
4
Com m unities
TREE COVER
SHRUB COVER
HERB COVER
GRASS COVER
Linear (TREE COVER)
Linear (SHRUB COVER)
Linear (GRASS COVER)
Linear (HERB COVER)
40
30
20
10
0
Slope
Level Gentle Moderate Steep Very
Steep Erosion Class
1
2
3
4
Percentage Rockiness
a)
0
1
2
3
4
Com m unities
SLOPE
EROSION
ROCKINESS
Linear (ROCKINESS)
Linear (EROSION)
Linear (SLOPE)
b)
Figure 5:
Community ordination scatter diagrams depicting a) tree cover, shrub
cover, herb cover, and grass cover with trend lines portraying
tendencies in the aforementioned parameters from community 1 to
community 4; and b) slope, erosion and rockiness with trend lines
depicting inclinations of aforementioned parameters from community
1 to community 4.
93
Discussion and conclusion
There are relatively clear distinctions between the various communities identified at
the Blydeberg Conservancy. The stratification and classification using TWINSPAN
(Hill, 1979) and the refinement thereof using Braun-Blanquet procedures proved
successful as the various vegetation units are recognizable in the veld (Figure 4).
All plant communities identified at Blydeberg reflect some form of human related
impact. These are mostly historical and agriculturally related influences that are in
the process of self rectification to a more stable successional stage, with the
exception of the Diospyros mespiliformis Variant (community 4.4.2) occurring
within the Gymnosporia glaucophylla-Panicum maximum Woodland (community 4).
In this variant there are recent signs of large scale vegetation destruction through
clearing by a landowner. This is not consistent with the definition and objectives of
a conservancy, which is the conservation of the natural resources occurring within
the area, and should be addressed by all members of the conservancy.
According to Van Oudtshoorn (1999), the grass species Elionurus muticus is
considered to be mostly an Increaser IIb that occurs in broken country of lower
rainfall areas, it grows on a variety of soil types with a preference for poor, stony
soils.
The presence of similar size and aged clumps of the shrub species
Dichrostachys cinerea tends towards poor veld conditions in certain areas.
A decline in the condition of the grass or herbaceous layer is typically accompanied
by an increase in the density of trees and shrubs (Smit et al., 1999). This can be
seen at Blydeberg (Figure 5a), where many of the low-lying areas have dense
woodlands and a poorly developed herbaceous layer, possibly due to long term
previous overgrazing by cattle, of which there is evidence.
94
Overgrazing by cattle has compromised the herbaceous layer by removing the
natural tree/grass competition factor, resulting in areas that appear to be in a semidegraded condition. According to (Donaldson, 1978; Dye & Spear, 1982; Moore et
al., 1985), woody species compete more successfully than grasses for resources
required for growth, whilst simultaneously tolerating utilisation better. This is due to
trees and shrubs having exclusive access to soil water at depth in the soil profile
(Dye & Spear, 1982).
Grasses are unable to survive in dense woody communities as they are deprived
of water and sunlight, however trees can survive unaffected in dense grass
communities. Woody species are partially protected against excessive utilisation
as part of their canopy is often out of reach from browsing animals. This is not the
case for grasses which are mostly within reach for grazers. Reduced competition
from grass communities in overgrazed areas leads to an increase in the density of
woody species.
In most cases these changes are irreversible due to woody
species out competing grasses for moisture (Smit et al., 1999). Over time, fuel
loads are reduced in areas with a degraded grass layer and fire can no longer be
used as an effective means of bush control.
An understanding of the various plant communities with their associated habitats is
fundamentally important and are deemed critical for devising sound management
and conservation strategies for any protected area (Smit et al., 1999). In order to
develop suitable management plans and to determine habitat suitability for various
species of animals, it is important that more detailed vegetation studies be
undertaken to compile an inventory of the flora of a conservation area (Brown &
Bredenkamp, 1994).
95
There are no known detailed vegetation maps for the study area.
Previous
vegetation studies were conducted on broader plant communities within the region
(Deall, 1985; Deall et al., 1989; Mathews, 1991; Matthews et al., 1996; Marais,
2004). Data obtained from this initial assessment could be incorporated into a
larger vegetation map for the entire Blydeberg conservancy.
The information
generated could be utilised as part of a management plan for the area and would
form the basis thereof.
Ongoing analysis of the areas vegetation over the medium to long term is
recommended as it would provide an accurate data set that could serve as
guidelines for future management actions. From such data, trends in vegetation
could be identified and any negative tendencies with their causes could be rectified
before such leads to further degradation.
This study forms part of a larger study on the foraging ecology of a single troop of
vervet monkeys (Chlorocebus aethiops) in Mixed Lowveld Bushveld and Sour
Lowveld Bushveld of the Blydeberg Conservancy. To date there are no formal
management plans for vervet monkeys. This is attributed to the limited knowledge
of vervets and their utilisation of, and impacts on ecosystems. Plant communities
identified and described in this study form part of the study area containing the
study troop’s home range, thereby providing detailed data on various plant species
as well as habitats occurring within their home range.
This study provides
essential information pertaining to community utilisation within the study troops’
home range.
Data obtained from this study as mentioned previously will also
provide base line information for management plans of the study area, providing
information that could be used to assist with the development and implementation
of a set of guidelines for the management of vervets in similar areas. Without the
classification and delineation of the different plant communities, food availability
and utilisation in such communities by the vervets could not have been determined.
96
Having knowledge of vervet habitat utilisation aids in management’s decision
making.
With regards to habitat utilisation, the vervets had ten plant communities, subcommunities and variants available to them within their home range. Of the ten
available plant communities, sub-communities and variants, they utilized only six
during the study period i.e. sub-community 2.2 (Combretum imberbe-Acacia
nigrescens Woodland), community 3 (Acacia nigrescens-Combretum apiculatum
Woodland),
sub-community
4.1
(Balanites
maughamii-Panicum
maximum
Woodland), sub-community 4.2 (Sclerocarya birrea-Panicum maximum Woodland),
sub-community 4.3 (Combretum zeyheri-Panicum maximum Woodland), and
variant 4.4.1 (Pappea capensis Variant)(Barrett, 2005).
Of the six plant
communities, sub-communities and variants utilized, sub-community 4.2 was used
the most during both the wet and the dry season. Community 3 and variant 4.4.1
were only used during the dry season, whereas, the other communities, subcommunities and variants were randomly utilized across both seasons (Barrett,
2005).
There are no specific management plans for the Blydeberg Conservancy and it
appears as though there is very little consensus on the management of the area
between the different land owners and involved parties.
Setting up goals and
objectives for the management of the area would be crucial to its continued
existence over the medium to long term and such should be seen as a priority by
all involved.
It is suggested that all land owners meet and agree to a set of
minimum objectives for the area.
These objectives must be obtainable under
current conditions where there are conflicting interests between owners.
A
baseline management plan needs to be established where the natural vegetation is
managed and protected as it forms the basis of any current or future endeavour.
97
A veld management program needs to be implemented as a priority so that a
thorough knowledge of the ecosystem and its functioning can be understood and
managed to the benefit of all animals and humans in the area. By knowing the
seasonal utilisation of plant communities by vervets, a management plan can be
developed that would ensure the minimum disturbance to these communities.
Such a management plan should prevent the vervets from seeking additional food
sources in the adjacent commercial plantations.
98
Acknowledgements
Professor D. Mitchell is thanked for allowing the research to take place on his
privately owned portion of the Blydeberg Conservancy.
This research was
financially supported by the National Research Foundation.
References
ARNOLD, T.H. & DE WET, B.C. 1993. Plants of Southern Africa: Names and
distribution. Memoirs of the botanical Survey of South Africa., 62: 1-825.
BARBOUR, M.G., BURK, J.H. & PITTS, W.D. 1987. Terrestrial Plant Ecology. 2nd
ed. Massachusetts: The Benjamin/Cummings Publishing Company, Inc.
BARRETT, A.S.
2005.
Foraging ecology of the Vervet Monkey (Chlorocebus
aethiops) in Mixed Lowveld Bushveld and Sour Lowveld Bushveld of the
Blydeberg
Conservancy,
Northern
Province,
South
Africa.
Mtech.
dissertation. University of South Africa, Pretoria.
BEZUIDENHOUT, H. 1993. Syntaxonomy and synecology of Western Transvaal
Grasslands. Ph.D. dissertation, University of Pretoria, Pretoria.
BEZUIDENHOUT, H. 1996. The major vegetation communities of the Augrabies
Falls National Park, northern Cape. 1. The southern section. Koedoe, 39: 724.
BOOTH, A.H. 1979. The Distribution of Primates in the Gold Coast. In: Sussman,
R.W.
(Ed.).
Primate Ecology.
Problem-oriented field studies.
Chichester & New York: chap. 7: 139-154.
99
Wiley,
BREDENKAMP, G.J., JOUBERT, A.F. & BEZUIDENHOUT, H.
1989.
A
reconnaissance survey of the vegetation of the plains in the PotchefstroomFochville-Parys Area. South African Journal of Botany, 55: 199-206.
BREDENKAMP, G.J. & BEZUIDENHOUT, H. 1995. A proposed procedure for the
analysis of large data sets in the classification of South African Grasslands.
Koedoe, 38(1): 33-39.
BREDENCAMP, G. & VAN ROOYEN, N. 1998a. Mixed Lowveld Bushveld. In:
Low, A.B. & Rebelo, A.G. (eds) Vegetation of South Africa, Lesotho and
Swaziland. 2nd ed. Dept Environmental Affairs and Tourism, Pretoria.
BREDENCAMP, G. & VAN ROOYEN, N. 1998b. Sour Lowveld Bushveld. In:
Low, A.B. & Rebelo, A.G. (eds) Vegetation of South Africa, Lesotho and
Swaziland. 2nd ed. Dept Environmental Affairs and Tourism, Pretoria.
BROWN, L.R.
1997.
A plant ecological and wildlife management plan of the
Borakalalo Nature Reserve, North-west Province.
Ph.D.
dissertation.
University of Pretoria, Pretoria.
BROWN, L.R. & BREDENKAMP, G.J. 1994. The phytosociology of the southern
section of the Borakalalo Nature Reserve, South Africa. Koedoe, 37: 59-72.
BROWN, L.R., BREDENKAMP, G.J. & VAN ROOYEN, N.
1996.
The
phytosociology of the northern section of the Borakalalo Nature Reserve.
Koedoe, 39(1): 9-24.
BUCKLE, C.
1992.
Landforms in Africa: An Introduction to Geomorphology.
Essex: Longman Group Ltd.
100
CAUGHLEY, G. & SINCLAIR, A.R.E. 1994. Wildlife Ecology and Management.
Canada: Oxford University Press.
CILLIERS, S.S.
1998.
Potchefstroom,
Phytosociological studies of urban open spaces in
North
West
Province,
South
Africa.
Ph.D.
thesis,
Potchefstroom University for CHE, Potchefstroom.
DEALL, G.B. 1985. A plant-ecological study of the Eastern Transvaal escarpment
in the Sabie area. M.sc. Thesis, University of Pretoria, Pretoria.
DEALL, G.B., THERON, G.K., WESTVAAL, R.H. 1989. The vegetation ecology of
the Eastern Transvaal Escarpment in the Sabie area.
2.
Floristic
classification. Bothalia, 19: 69-89.
DONALDSON, C.H. 1978. Evaluation of Cenchrus ciliaris: II. A comparison of
bushveld, de-bushed veld and bushveld combined with Cenchrus pastures.
Proc. Grassld Soc. Sth. Afr, 2:137-141.
DYE, P.J. & SPEAR, P.T.
1982.
The effects of bush clearing and rainfall
variability on grass yield and composition in south-west Zimbabwe.
Zimbabwe Journal of Agricultural Resources, 20: 103-118.
ECKHARDT, H.C. 1993. A synecological study of the vegetation of the northeastern Orange Free State. M.Sc. thesis. University of Pretoria, Pretoria.
FEDIGAN, L. & FEDIGAN, L.M. 1988. Cercopithecus aethiops: a review of field
studies. In: Gautier-Hion A., Bourlière F., Gautier J., Kingdon J. (Eds). A
Primate Radiation: Evolutionary Biology of the African Guenons. Cambridge
University Press, New York: pp 389-411.
101
FULS, E.R. 1993. Vegetation ecology of the northern Orange Free State. Ph.D.
dissertation. University of Pretoria, Pretoria.
FULS, E.R., BREDENKAMP, G.J. & VAN ROOYEN, N.
1992.
The plant
communities of the undulating grassland of Vredefort – Kroonstad – Lindley –
Heilbron area, northern Orange Free State. South African Journal of Botany,
58: 224-230.
HARRISON, M.J.S.
1983. Patterns of range use by the green monkey,
Cercopithecus sabaeus, at Mt. Assirik, Senegal. Folia Primatol, 41: 157-179.
HARRISON, M.J.S. 1984. Optimal foraging strategies in the diet of the green
monkeys, Cercopithecus sabaeus, at Mt. Assirik, Senegal. Int. J. Primatol, 5:
435-471.
HENNEKENS, S.M. 1996. Megatab: a visual editor for phytosociological tables.
Ulft: Giesen.
HENNEKENS, S. 1998. TURBOVEG: Clipper database management software for
storage, selection, and export of vegetation data (relevés). Netherlands.
HILL, M.O. 1979. TWINSPAN: A Fortran program for arranging multivariate data
in an ordered two-way table by classification of individuals and attributes.
New York: Cornell University.
ISBELL, L.A., PRUETZ, J.D. & YOUNG, T.P.
1998.
Movements of vervets
(Cercopithecus aethiops) and patas monkeys (Erythrocebus patas) as
estimators of food resource size, density and distribution.
Sociobiol, 42: 123-133.
102
Behav.
Ecol.
KENT, M. & COKER, P. 1997. Vegetation Description and Analysis – A Practical
Approach. New York: John Wiley & Sons.
KINGDON, J. 1997. The Kingdon field guide to African Mammals. Academic
Press, New York: Natural World.
KOOIJ, M.S., BREDENKAMP, G.J. & THERON, G.K. 1990. Classification of the
vegetation of the B land type in the north-western Orange Free State. South
African Journal of Botany, 56: 309-318.
LAND TYPE SURVEY STAFF. 1989. Land types of the maps 2330 Tzaneen,
2430 Pilgrims Rest. Memoirs on the Agricultural Natural Resources of South
Africa, 12.
LEE, P.C. & HAUSER, M.D.
1998.
Long-term consequences of changes in
territory quality on feeding and reproductive strategies of vervet monkeys.
Journal of Animal Ecology, 67: 347-358.
MARAIS, A.J.
2004.
Resource utilisation of the chacma baboon in different
vegetation types in north-eastern mountain sour veld, Blyde Canyon Nature
Reserve. Mtech. dissertation. University of South Africa, Pretoria.
MATTHEE, J.F. & VAN SCHALKWYK, C.J. 1984. A Primer on Soil Conservation.
Bulletin No. 399., Dept of Agriculture. Government Printer, Pretoria.
MATTHEWS, W.S. 1991. Phytosociology of the North-eastern Mountain sourveld.
Msc. Thesis, University of Pretoria, Pretoria.
103
MATTHEWS, W.S., BREDENKAMP, G.J. VAN ROOYEN, N.
1994. The
phytosociology and syntaxonomy of relative low-altitude areas in the Northeastern Mountain Sourveld, in the eastern Transvaal escarpment region.
Koedoe, 37(2).
MOORE, A., VAN NIEKERK, J.P., KNIGHT, I.W. & WESSELS, H. 1985. The
effect of Tebuthiuron on the vegetation of the thorn bushveld of the northern
Cape: a preliminary report. J. Grassld Soc. Sth. Afr, 2: 7-10.
MUELLER-DOMBOIS, D. & ELLENBERG, H.
1974.
Aims and methods of
vegetation ecology. New York: Wiley & Sons.
OATES, J.F. 1996. African Primates Status Survey and Conservation Action plan.
IUCN/SSC Primate Specialist Group. S.I.
PRUETZ, J.L. & ISBELL, L.A. 2000. Correlations of food distribution and patch
size with agonistic interactions in female vervets (Chlorocebus aethiops) and
patas monkeys (Erythrocebus patas) living in simple habitats. Behav. Ecol.
Sociobiol, 49: 38-47.
SKINNER, J.D. & SMITHERS, R.H.N.
1990.
The Mammals of the Southern
African Subregion. 2nd ed. South Africa: University of Pretoria.
SMIT, G.N., RICHTER, C.G.F. & AUCAMP, A.J. 1999. Bush encroachment: An
approach to understanding and managing the problem. In: Veld Management
in South Africa, ed. N. Tainton. University of Natal Press.
SOIL CLASSIFICATION WORKING GROUP.
taxonomic system for South Africa.
Resources of South Africa, 15: 1-257.
104
1991.
Soil classification a
Memoirs on the Agricultural Natural
STRUHSAKER, T.T. 1967. Ecology of Vervet Monkeys (Cercopithecus aethiops).
Ecology, 48: 891-904.
TUELLER, P.T. 1988. Vegetation science applications for rangeland analysis and
management. Dordrecht: Kluwer Academic Publishers.
TYSON, P.D. & PRESTON-WHYTE, R.A. 2000. The Weather and Climate of
Southern Africa. Cape Town: Oxford University Press.
VAN DER SCHIJFF, H.P. 1963. A preliminary account of the vegetation of the
Mariepskop Complex. Transvaal Provincial Administration. Fauna and Flora,
14: 42-53.
VAN DER SCHIJFF, H.P. & SCHOONRAAD, E.
1971.
The flora of the
Mariepskop Complex. Bothalia, 10(3): 461-500.
VAN OUDTSHOORN, F. 1999. Guide to grasses of southern Africa. Pretoria:
Briza Publications.
VAN ROOYEN, N., THERON, G.K. & GROBBELAAR, N.
1981.
A floristic
description and structural analysis of the plant communities of the Punda
Milia-Pafuri-Wambiya area in the Kruger National Park, Republic of South
Africa. 1. The hygrophilous communities. South African Journal of Botany,
47: 213-246.
VAN ZYL, D.
2003.
South African Weather and Atmospheric Phenomena.
Pretoria: Briza Publications.
105
VISSER, D.J.L. (ed.).
1989.
The Geology of the Republics of South Africa,
Transkei, Bophuthatswana, Venda and Ciskei and the Kingdoms of Lesotho
and Swaziland.
Geological Survey, Explanation of the 1: 1 000 000
Geological Map, 4th ed. Government Printer, Pretoria.
WALRAVEN, F.
1989.
The Geology of the Pilgrim’s Rest Area.
Geological
Survey, Explanation of Sheet 2430. Government Printer, Pretoria.
WHITTEN, P.L.
1988. Effects of patch quality and feeding subgroup size on
feeding success in vervet monkeys (Cercopithecus aethiops).
105: 35-52.
106
Behaviour,
CHAPTER 6
Habitat utilisation and food selection by
vervet monkeys (Chlorocebus aethiops) in South African Bushveld.
Barrett, A.S.1, Brown, L.R.1, Barrett, L.2,3 and Henzi, S.P.2,4
1. Applied Behavioural Ecology and Ecosystems Research Unit, University of
South Africa
2. Behavioural Ecology Research Group, University of KwaZulu-Natal
3. School of Biological Science, University of Liverpool
4. Department of Psychology, University of Central Lancashire.
Abstract
A 12-month study was conducted in the Northern Province of South Africa to
determine the seasonal habitat utilisation and food selection of a free ranging troop
of vervet monkeys (Chlorocebus aethiops).
It was hypothesized that the study troop would utilize varying proportions of their
habitat based on seasonality. The study troop’s habitat was mapped and plant
communities occurring within their home range was determined.
Seasonal
community utilisation did not differ significantly.
It was suggested that the study troop would cover more area during the dry season
than during the wet season. This was found to be true.
107
It was anticipated that the study troop would utilize more of their home range
during the dry season than during the wet. Such was the case - they used more of
what was available to them during the dry season than during the wet season.
It was predicted that the vervets would travel further during the dry season, thus
utilizing a larger area of their home range than during the wet season when food
sources are more abundant and accessible. This was the case for the study troop
- they covered significantly more area during the dry season.
It was expected that a larger variety of foods would be consumed during the wet
rather than during the dry season. This was observed. It has been suggested that
vervet diets are usually restricted to a small number of staple foods, with a wider
supplementation based on seasonality (Harrison, 1983a; Lee, 1984; Whitten, 1988;
Lee & Hauser, 1998). The aforementioned appeared to be true for the research
troop that had certain staple food sources making up the mainstay of their diet, with
a large variety of other foods used for purely supplementary purposes as and when
such became available.
Introduction
The opportunistic omnivery that characterizes the cercopithecines, together with
locomotory and postural adaptations that reduce their reliance on continuous
canopy have resulted in vervets being the most widely-distributed species in the
guenon group (Struhsaker, 1967a).
Vervets are well adapted to practically any wooded habitats outside equatorial rain
forests. They spend a large portion of their moving time on the ground making
them semi-terrestrial (Dunbar & Barrett, 2000).
They are typically an ‘edge’
species, never venturing too far from the cover of trees and the protection such
provides.
108
Vervets are always found relatively close to water and are associated with the
accompanying riverine or gallery forest vegetation (Nagel, 1973; Harrison, 1983b;
Skinner & Smithers, 1990; Estes, 1991; Nakagawa, 1999; Dunbar & Barrett, 2000;
Zinner et al., 2002). In Eritrean vervet home-ranges, proportions of forested and
wooded areas were significantly higher than expected, with trees serving as main
food sources and for sleeping sites. Large portions of agricultural areas were also
included in their home-ranges (Zinner et al., 2002). Vervets are non-specialist
feeders adapted to strongly fluctuating resource availability (Wrangham &
Waterman, 1981; Harrison, 1984; Lee & Hauser, 1995). Their diet includes fruits,
seeds, pods, flowers, leaves, buds, sap, gum, grasses, invertebrates and,
occasionally vertebrates such as small reptiles, nestling birds and eggs (Skinner
and Smithers, 1990).
Despite the attendant ability to respond to local circumstances that their broad
latitudinal distribution indicates (i.e. their ecological plasticity), few detailed
ecological studies of the species have been undertaken in the tropics (Struhsaker,
1967c; Harrison, 1983b, 1984; Whitten, 1988; Lee & Hauser, 1998; Isbell et al.,
1998; Pruetz & Isbell, 2000). At these low latitudes overall habitat productivity is
high and seasonal variability, while obviously evident is relatively constrained
(Caughley & Sinclair, 1994).
A fuller understanding of the extent of vervet
ecological flexibility and the factors that might limit their distribution both broadly
and locally is likely to be derived from data collected at higher latitudes, where
overall productivity is generally much lower and therefore likely to magnify any
seasonal effects on food choice and habitat use by omnivores (Bronikowski &
Altmann, 1996; Lee & Hauser, 1998; Dunbar & Barrett, 2000). Lawes et al. (1990)
for example, found that sources of protein rich foods were the critically limiting
factor for samango monkey (Cercopithecus mitis) foraging behaviour.
109
Samangos are the most widely distributed of the arboreal guenons and cope with
seasonal declines in the availability of insects at high latitudes by ingesting large
amounts of foliage and flowers, as well as where necessary unripe fruit and mature
leaves. It has been argued that this ability to turn to leaves, made possible by a
suite of gut adaptations, is responsible for the radiation of samangos out of the
tropics.
Comparison of the gut morphology of vervet and samango monkeys
indicate that vervets do not share these adaptations, at least not to the same
extent (Bruorton et al., 1991), suggesting that the successful response of vervets to
higher latitudes rests on different foundations.
In the Kala Maloue National Park, Cameroon, a distinct seasonal change in the diet
of Cercopithecus aethiops tantalus was observed by Nakagawa (1999 & 2003).
According to Nakagawa (1999) and Zinner et al. (2002), during the dry season
more time is spent feeding on woody plants than on grasses, with slightly more
time spent in grasslands during the wet season.
According to Brennan et al.
(1985), seasonality has a definite influence on the diet of vervets in a tourist-lodge
habitat in Amboseli National Park, Kenya: where vervets around the lodge become
more dependent on human foods during the dry season when fewer natural food
sources are available, often leading to conflict with man.
Due to there not being much of a variety to choose from at some other temperate
sub-tropical sites, vervets utilized more of what was available to them seasonally
i.e. vervets in north central Kenya were restricted to what Pruetz & Isbell (2000)
refer to as simple habitats with small randomly distributed food patches. In such
patches the vervets would maximize the use of their resources, feeding on various
parts of a particular plant species as such became available i.e. leaves, flowers,
seeds, exudates, insects attracted to the plants and even swollen thorns were
utilized.
110
According to Pruetz & Isbell (2000), Acacia drepanolobium accounted for over half
of the vervet’s diet when they were in A. drepanolobium habitat, and Acacia
xanthophloea similarly accounted for more than half of their diet when they were in
A. xanthophloea habitat.
Regardless of the precise dietary response to latitude and seasonality, there is also
indirect energetic consequences to a reduction in food availability that result from
the need to cover a greater area, and hence travel further in order to maintain
adequate intake. Other things being equal, it is expected that social primates will
extend both the size of their home range and their day range distances as food
availability declines (Adeyemo, 1997; Baldellou & Adan, 1998). Vervet monkeys
are territorial (Henzi, 1984; Skinner & Smithers, 1990; Cheney & Seyfarth, 1992;
Estes, 1992; Dunbar & Barrett, 2000) and, while territory size will reflect local
resource density, it may well be that vervets at high latitude are constrained in the
extent to which they can respond when resources decline. Alternatively, they may
work during times of good resource availability to maintain territories of a sufficient
size to support them when resources are scarcer.
We begin to address these issues with data from a free-ranging troop of vervet
monkeys occupying temperate sub-tropical bushveld in the Northern Province,
South Africa. Although the study population is not near the limit of the species
distribution, which lies in the Western Cape Province, it is to our knowledge the
southern most population for which detailed ecological information is available. In
this paper, we present data on diet and habitat use and assess the animals’
response to seasonal variation in resource availability.
111
Methods
Study animals
A troop of vervet monkeys living on the Blydeberg Conservancy was habituated.
At the end of the study period the troop (N=33) comprised 5 adult males, 8 adult
females and 20 non-adults.
Study site
The Blydeberg Conservancy is approximately 3000 ha in size, located along the
great escarpment in the Northern Province of South Africa, Longitude 30° 27’ to
25° 56’ E and Latitude 24° 23’ to 24° 28’ S. Altitude ranges from 350 m to 800 m
above sea level (Bredenkamp & Van Rooyen, 1998a, 1998b). The study area
constitutes the farms Dunstable (farm number 230) and Jongmanspruit (farm
number 234) (Figure 1).
Figure 1:
A map of the study area within the Northern Province of South Africa.
112
The topography of the area is mountainous in the south to flat and open in the
north. There are several small mountain streams running from the watershed in
the Drakensberg Mountains that make up the southern boundary of the
conservancy, into the Blyde River to the north of the conservancy.
The climate along the escarpment is mostly mild (Figure 2). Mean temperature of
the hottest months (December 2003 and January 2004) was 27.2oC, whilst that of
the coldest month (July 2003) was 19.9oC. Average annual temperature over the
last five years has increased from 21.8 °C in 1999/2000 to 22.9 °C in 2003/2004 –
an average increase of 0.2 °C per year. Average temperature for the study period
was 0.6 °C above the average for the last five years, which was 22.3 °C. Mean
monthly rainfall for the study period was 44.6 mm, with no rainfall being recorded
for July and August 2003, and only 2.5 mm for October 2003. The highest rainfall
of 136.5 mm was recorded in March 2004. Rainfall for the study period (534.6
mm) was below average, with the mean for the previous five years being 561 mm.
160
30
136.5
118.4 121.4
Rainfall (mm)
120
25
100
20
80
15
60
44.8
42
38
40
20
9.5
14.7
0
0
6.8
2.5
5
0
-20
May- Jun- Jul-03 Aug- Sep- Oct- Nov- Dec- Jan- Feb- Mar- Apr03
03
03
03
03
03
03
04
04
04
04
Months
Total rainfall
Figure 2:
Average temperature
Average rainfall
Rainfall and temperature summary for the study period.
113
10
0
Temperature (deg C)
140
Data collection
i. Activity and diet.
The troop was followed on foot from a distance of 5-15 m for as long as possible
on each day of data collection. Data were collected over an average of eleven
days a month for a twelve-month period (1 May 2003 to 30 April 2004), resulting in
132 days of data, 30 of which were from dawn to dusk, the rest being dependent
on when and for how long the troop was located. Data were recorded using a
PALM HANDSPRINGTM data-logger, pre-loaded with PENDRAGON FORMSTM
software.
Scan samples were drawn approximately every thirty minutes from all
visible animals (Altmann, 1974).
Five mutually exclusive categories of activity were recognized: foraging (feeding,
actively searching for or processing food), socializing (playing, aggression,
grooming, maternal or paternal, mating), moving, resting and drinking.
When
animals were recorded as foraging, we identified the food source and the specific
part being consumed. A total of 4504 individual scans were collected.
ii. Habitat structure
A GARMIN 12 XLTM handheld GPS with CARTALINXTM mapping software (Hagan
et al., 1998) was used to digitize a map of the study site. A map of vegetation
types and habitat structure was generated using a 1:10 000 digitized ortho photo
for the Blydeberg area.
The study area was stratified into physiognomic-
physiographic units i.e. the vegetation of the study area was divided up broadly into
obviously different vegetation types by examining the ortho photo.
Sampling
quadrats were then allocated to each separately identified vegetation unit in a
randomly stratified manner (Barbour et al., 1987; Kent & Coker, 1997).
114
A total of 49 sample plots were located within these units to ensure all variations in
vegetation were considered and sampled.
Plot sizes were fixed at 400 m2
(Barbour et al., 1987; Brown & Bredenkamp, 1994; Brown, 1997). In each sample
plot all plant species were recorded and cover abundance was assessed using the
Braun-Blanquet cover abundance scale (Mueller-Dombois & Ellenberg, 1974;
Barbour et al., 1987). This component of the fieldwork was undertaken during
April, May, and June 2003 and in January 2004. Floristic Data were analyzed
according
to
Braun-Blanquet
procedures
using
the
TURBOVEGTM
suite
(Hennekins, 1998), which includes the Two-way indicator species analysis
multivariate classification technique (TWINSPANTM – Hill, 1979), for deriving an
initial approximation of the main plant communities. This numerical classification
technique is regarded as a successful approach to vegetation classification by
various
phytosociologists
(Brown
&
Bredenkamp,
1994;
Bredenkamp
&
Bezuidenhout, 1995; Brown et al., 1996; Cilliers, 1998).
The visual editor MEGATABTM (Hennekens, 1996) was used to generate a
phytosociological table. Using the phytosociological table and habitat information
collected during sampling in the field, different plant communities were identified,
described and ecologically interpreted. Further refinement of the classification was
undertaken through the application of Braun-Blanquet procedures according to
(Barbour et al., 1987; Bredenkamp et al., 1989; Kooij et al., 1990; Bezuidenhout,
1993; Eckhardt, 1993; Brown & Bredenkamp, 1994; Kent & Coker, 1997).
iii. Food and community Selection
Electivity of the main plant species consumed was calculated using Ivlev’s
electivity index i.e. Species Electivity = (r1-n1)/(r1+ n1) where r1 = proportion of
food item in diet and n1 = proportion of food item in home range (Krebs, 1989).
115
For species electivity the proportion of a food item in their diet was calculated as a
percentage of all plants in their diet, and a proportion of a food item in the home
range was calculated as a percentage of all species occurring within the home
range.
Similarly, electivity of available plant communities was also calculated using Ivlev’s
electivity index i.e. Community Electivity = (r1-n1)/(r1+ n1) where r1 = proportion of
community utilized and n1 = proportion of community available in home range. For
community electivity the proportion of a community utilized was calculated as a
percentage of the overall communities’ size, and a proportion of a communities
availability within the home range was calculated as a percentage of the size of all
communities.
Values for Ivlev’s electivity index range between -1 and 1; >0 indicates positive
selection of a food item, <0 indicates selection against, or avoidance of a food
item.
iv. Day range length and home range area estimation.
When the troop was located, GPS co-ordinates of their centre of mass was
recorded. If the troop started moving, the subsequent route would be mapped by
recording a GPS co-ordinate every 10 seconds until they stopped moving for a
continuous period exceeding 5 minutes. The co-ordinates of their new location
would then again be recorded. This was done for three days a month to provide
estimates of home range area. Co-ordinates collected were plotted onto a 1:10
000 ortho-photo of the study area forming a backdrop to simplify analysis. To
estimate home range size, all day journeys were combined to generate a bounding
polygon.
116
GIS software utilized for analyses uses fractal theory and a combination of simple
algorithms for its area calculations i.e. minimum convex polygons and a series of
increasing sized ‘gliding boxes’ are used to sample spatial or gridded data. For
information on the specifics of algorithms used in GIS software, refer to Bartlett
(1978), Davis (1986) and Allain & Cloitre (1991).
A census of the various animal species occurring in the study area was undertaken
to determine diversity and numbers. Combinations of the strip/line transect and
known group counts census methods were used (Collinson, 1985). Five transect
lines were set out with a combined length of 17.3km. Transects were walked bimonthly for 5 months. Transects were selected using stratified random sampling
techniques and covered most of the potential habitats.
Mountain tops were
excluded as they could not be reached. Counts of known vervet groups were
undertaken whenever these were observed.
By the end of the study period two additional vervet troops had been identified: a
troop on the adjacent farm Dunstable consisting of approximately eleven
individuals, and another troop of at least eight individuals residing in the proximity
of the conservancy’s entrance gate.
Both troop sizes are only of individuals
actually observed and are likely to be underestimates (Figure 6b).
v. Statistical analysis
SPSSTM (version 11.5.0) was used for all statistical analyses. All tests were twotailed with alpha set at 0.05.
117
Results
Habitat utilisation
Several distinct physiognomically physiographic plant communities were identified
within the study area.
Figure 3 depicts the various plant communities.
Descriptions of plant communities are as follows:
1. Eragrostis lehmanniana-Grewia flava Shrubland.
1.1 Heteropogon contortus-Grewia flava Shrubland.
1.2 Ziziphus mucronata-Grewia flava Shrubland.
2. Bridelia mollis-Acacia nigrescens Woodland.
2.1 Berchemia zeyheri-Acacia nigrescens Woodland.
2.2 Combretum imberbe-Acacia nigrescens Woodland.
3. Acacia nigrescens-Combretum apiculatum Woodland.
4. Gymnosporia glaucophylla-Panicum maximum Woodland.
4.1 Balanites maughamii-Panicum maximum Woodland.
4.2 Sclerocarya birrea-Panicum maximum Woodland.
4.3 Combretum zeyheri-Panicum maximum Woodland.
4.4 Asparagus setaceus-Philenoptera violacea Woodland.
4.4.1 Pappea capensis Variant.
4.4.2 Diospyros mespiliformis Variant.
118
Figure 3:
Vegetation map of the study area depicting various communities, subcommunities and variants.
Table 1 is a breakdown of seasonal community, sub-community and variant
utilization and shows that community 3 and variant 4.4.1 were only used during the
dry season; whereas the other communities, sub-communities and variants were
used across both seasons.
119
Table 1:
Comms in
Blydeberg
Communities utilized seasonally by the study troop.
4.3
Comm Description
Eragrostis lehmanniana-Grewia
flava Shrubland
Heteropogon contortus-Grewia
flava Shrubland
Ziziphus mucronata-Grewia flava
Shrubland
Bridelia mollis-Acacia nigrescens
Woodland
Berchemia zeyheri-Acacia
nigrescens Woodland
Combretum imberbe-Acacia
nigrescens Woodland
Acacia nigrescens-Combretum
apiculatum Woodland
Gymnosporia glaucophyllaPanicum maximum Woodland
Balanites maughamii-Panicum
maximum Woodland
Sclerocarya birrea-Panicum
maximum Woodland
Combretum zeyheri-Panicum
maximum Woodland
4.4
4.4.1
4.4.2
Asparagus setaceus-Lonchocarpus
capassa Woodland
Pappea capensis Variant
Diospyros mespiliformis Variant
1
1.1
1.2
2
2.1
2.2
3
4
4.1
4.2
In Territory
Utilised Utilised
Comm Comm
Dry
Wet
in
Total Season Total
Size
% Representation of Main Plant sp.
(ha) AS
(ha)
(ha) Territory (ha) Utilised (ha)
BZ CA DA DM FS
PA
TD
(193)
No
--
--
--
--
-- --
--
--
--
--
--
--
--
20
No
--
--
--
--
-- --
--
--
--
--
--
--
--
173
No
--
--
--
--
-- --
--
--
--
--
--
--
--
(415)
No
--
--
--
--
-- --
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
189 Wet/Dry
23.7
0.2
3.0 5.76
8.64 0.00 0.00
2.89 2.89 11.53 0.00
0.1 0.00
0.00 0.00 0.10
0.05 0.00
226
No
189
Yes
48
Yes
48
Dry
0.4
0.0
--
No
--
--
--
--
43
Yes
43 Wet/Dry
9.0
0.5
1.3 0.00
0.00 0.00 0.00
0.82 0.00
1.64 0.00
5
Yes
5 Wet/Dry
2.6
0.7
0.6 0.00
0.00 0.00 0.00
0.00 0.00
0.00 0.00
51
Yes
51 Wet/Dry
41.4
7.2
6.7 0.00
5.05 0.00 0.00 20.17 0.00 40.31 0.00
-7
54
816
No
Yes
No
-0.1
0.0
77.2
-0.0
-8.6
-7
-343
-Dry
--
-- --
-- --
-0.1
-11.7
--
--
--
--
0.00 0.00
--
--
--
--------0.00 0.03 0.02 0.00 0.00 0.06 0.03 0.03
--------5.76 13.72 0.02 0.10 23.93 2.94 53.51 0.03
AS=Acacia schweinfurthii, BZ=Berchemia zeyheri, CA=Celtis africana, DA=Dalbergia armata, DM =Diospyros mespiliformes, FS=Ficus sur, PA=Peltophorum
africanum, TD=Trichilia dregeana
Community utilisation was as follows (Table 1):
•
Sub-community 2.2 made up 55.1 % of the study area, during the wet
season they used 0.1 % of it and during the dry season they used 1.6 % of
•
it.
•
did not use it and during the dry season they used 0.2 % of it.
Community 3 made up 14.0 % of the study area, during the wet season they
Sub-community 4.1 made up 12.5 % of the study area, during the wet
season they used 1.1 % of it and during the dry season they used 3.0 % of
•
it.
•
they used 13.4 % of it and during the dry season they used 13.1 % of it.
Sub-community 4.2 made up 1.5 % of the study area, during the wet season
Sub-community 4.3 made up 14.9 % of the study area, during the wet
season they used 14.2 % of it and during the dry season they used 13.1 %
•
of it.
Variant 4.4.1 made up 2.0 % of the study area, during the wet season they
did not use it and during the dry season they used 1.2 % of it.
120
Figure 4 below depicts community utilisation across seasons for the study area and
study period. Community information shown is reflected in Table 1 above.
50
Size (ha)
40
30
20
10
0
2.2
3
4.1
4.2
4.3
4.4.1
Community
Community Size
Figure 4:
Combined Utilisation
Wet Utilisation
Dry Utilisation
Community utilisation. Community utilisation for wet and dry seasons
is depicted, with community size reflected for comparison.
Community utilisation was not significantly different for wet and dry seasons (u =
23.000, p = 0.4233).
Seasonal area traversed
It was predicted that the study troop would cover larger areas during the dry
season than during the wet season. This was the case (Table 2 and Figure 5).
Table 2 depicts area and average area covered in hectares (ha) with sub-totals for
wet and dry periods.
121
Table 2:
Seasonal average distances travelled and average area covered
monthly for the study period.
Date
May 1,
June 1,
July 1,
August 1,
September 1,
October 1,
May 1,
April 1,
November 1,
December 1,
January 1,
February 1,
March 1,
April 1,
FromNode ToNode
2003
23
24
2003
2003
37
38
2003
33
34
2003
33
34
2003
41
42
2004
31
32
Season
D
D
D
D
D
D
D
2003
2003
2003
2004
2004
2004
2004
W
W
W
W
W
W
W
31
7
18
3
33
38
AreaHa
0.82
0.67
1.31
1.95
0.58
1.17
0.28
0.97
32
1.32
8
0.69
19
0.96
2
0.45
33
0.40
0.33
17
1.15
0.76
Avg Ha
0.2982
0.2995
0.7247
1.0718
0.8619
1.1981
1.1474
0.5901
0.3317
0.5957
0.5466
0.7184
0.6769
1.1835
The study troop traversed a significantly larger area during the dry season
compared to that of the wet season (Chi 2 test: χ2 = 6.908; p = 0.0086; df = 1).
Area traversed during the dry season (Figure 5a) was more than double the area
covered during the wet season (Figure 5b) i.e. 76 ha and 37 ha respectively.
122
a)
Figure 5:
b)
Daily distances travelled and area covered by the study troop during
the study period. a) Represents movement patterns for the period
including May 2003 to October 2003 and May 2004 (dry season). b)
Represents movement patterns for the period including April 2003
and November 2003 to April 2004 (wet season).
123
Home range
The study troop’s home-range size was calculated as 77 ha, (Figure 6).
8
11
a)
Figure 6:
b)
Study troop home range during the study period.
Area was
calculated in ha using the area within the bounding polygon. a) Is
combined study troop wet and dry ranges – blue arcs are wet
season daily ranges and red arcs are dry season daily ranges. b) Is
bounding polygon for combined wet and dry ranges. Numbered
circles depict neighbouring troop locations and sizes as observed
during census transects walked.
124
Diet and food selection
The various food types that made up the vervets diet are depicted in Figure 7.
40
Percentage of Diet
35
30
25
20
15
10
5
Gum
Lichen
Stem
Seed
Grass
Pod
Other
Leaf
Fruit
Flower
Insect
0
Food Type
Dry
Figure 7:
Wet
Seasonal foraging. The graph depicts various food sources selected
for both dry and wet seasons.
Table 3 below shows whether significantly more of a particular food source was
consumed during the wet season.
125
Table 3:
Vervet food selection for the study period. Table reflects diet item,
Chi square test results and significance of diet items with regards to
wet season. Exceptions are marked and discussed.
Food eaten
Chi 2 test results
Significantly more
consumed during the
wet season
χ = 0.812; p = 0.3676; df =
2
Insect
1
χ2 = 12.233; p = 0.0005; df =
Flower
Leaf
1
Other - Debris/leaves
χ2 = 20.354; p < 0.0001; df =
on ground
1
χ2 = 1.292; p = 0.2557; df =
*
Yes
Yes
Yes
1
χ2 = 0.825; p = 0.3638; df =
Gum
No
1
χ2 = 6.951; p = 0.0084; df =
Lichen
No
1
χ2 = 9.466; p = 0.0021; df =
Stem
No *
1
χ2 = 41.007; p < 0.0001; df =
Seed
No
1
χ2 = 2.400; p = 0.1213; df =
Grass
Yes
1
χ2 = 2.129; p = 0.1445; df =
Pod
Yes
1
χ2 = 20.853; p < 0.0001; df =
Fruit
No
No
1
Significantly more consumed during the dry season
Figure 8 depicts the five most commonly utilized plant species for both the wet and
dry seasons.
126
6% 5%
15%
44%
30%
Diospyros mespiliformis
Ficus sur
Peltophorum africanum
Celtis africana
Acacia schweinfurthii
a)
15%
29%
16%
17%
23%
Berchemia zeyheri
Trichilia dregeana
Dalbergia armata
Ficus sur
Diospyros mespiliformis
b)
Figure 8:
Five most commonly utilized plant species for a) the wet and b) the
dry seasons. Pie charts show preferred plant species by season.
127
There were some species that were consumed across seasons as
they started fruiting during the wet season and continued into the dry
season.
Various plant species foraged on for both seasons were plotted as a cumulative
100
80
60
40
20
0
Species
Cumulative Percentage Species Contribution of various plant species
Diospyros mespiliformis
Ficus sur
Berchemia zeyheri
Trichilia dregeana
Peltophorum africanum
Dalbergia armata
Celtis africana
Rauvolfia caffra
Ficus thoningii
Commiphora harveyi
Eragrostis lehmanniana
Sclerocarya birrea
Ximenia caffra
Acacia schweinfurthii
Panicum maximum
Tacazzea apiculata
Dovyalis caffra
Markhamia zanzibarica
Ziziphus mucronata
Capparis tomentosa
Mystroxylon
Dichrostachys cinerea
Garcinia livingstonei
Gardenia volkensii
Lanea discolor
Ficus sycomorus
Grewia flava
Grewia flavescens
Acacia karroo
Ehretia rigida
Adansonia digitata
Albizia forbesii
Albizia versicolor
Dovyalis zeyheri
Elionurus muticus
Helinis integrifolius
Acacia caffra
Combretum imberbe
Dombeya rotundifolia
Philenoptera violacea
Aloe castanea
Strophanthus speciosus
percentage contribution (Figure 9).
Figure 9:
foraged on.
Table 4 depicts a breakdown of the various plant part percentages contributing
towards the study troops diet for the wet and dry seasons as shown in the
128
cumulative percentage contributions (Figure 9).
Percentage Contribution
Table 4:
Breakdown of various plant part percentages contributing towards the
study troops diet for the wet and dry seasons.
PLANTSPECIES
Diospyros mespiliformis
Ficus sur
Berchemia zeyheri
Trichilia dregeana
Peltophorum africanum
Dalbergia armata
Celtis africana
Rauvolfia caffra
Ficus thoningii
Commiphora harveyi
Eragrostis lehmanniana
Sclerocarya birrea
Ximenia caffra
Acacia schweinfurthii
Panicum maximum
Tacazzea apiculata
Dovyalis caffra
Markhamia zanzibarica
Ziziphus mucronata
Capparis tomentosa
Mystroxylon aethiopicum
Dichrostachys cinerea
Garcinia livingstonei
Gardenia volkensii
Lanea discolor
Ficus sycomorus
Grewia flava
Grewia flavescens
Acacia karroo
Ehretia rigida
Adansonia digitata
Albizia forbesii
Albizia versicolor
Dovyalis zeyheri
Elionurus muticus
Helinis integrifolius
Acacia caffra
Combretum imberbe
Dombeya rotundifolia
Lonchocarpus capassa
Aloe castanea
Strophanthus speciosus
% of
Total
Contribution Towards Tot % Dry
Contribution Towards Tot % Wet
Cumulative Tot % Tot % Dry
Dry
Dry
Dry
Dry
Dry
Dry
Wet
Wet
Wet
Wet
Wet
Wet
Wet
Dry
Wet Stem % Seed % Root% Pod % Flower % Fruit % Leaf % Stem % Seed % Root % Pod % Flower % Fruit % Leaf %
18.39
14.36
10.16
8.84
7.53
6.30
3.85
3.24
2.63
2.45
2.19
2.01
1.66
1.40
1.40
1.23
1.23
1.14
1.14
1.05
0.88
0.79
0.79
0.70
0.70
0.61
0.53
0.53
0.44
0.26
0.18
0.18
0.18
0.18
0.18
0.18
0.09
0.09
0.09
0.09
0.09
0.09
18.39
32.75
42.91
51.75
59.28
65.59
69.44
72.68
75.31
77.76
79.95
81.96
83.63
85.03
86.43
87.65
88.88
90.02
91.16
92.21
93.08
93.87
94.66
95.36
96.06
96.67
97.20
97.72
98.16
98.42
98.60
98.77
98.95
99.12
99.30
99.47
99.56
99.65
99.74
99.82
99.91
100.00
13.31
8.93
0.61
0.96
4.55
0.61
1.75
0.18
0.53
0.00
1.05
0.18
0.00
1.40
0.00
0.26
0.00
0.00
0.00
0.00
0.00
0.79
0.00
0.00
0.00
0.26
0.26
0.44
0.35
0.00
0.00
0.18
0.00
0.00
0.00
0.00
0.09
0.09
0.09
0.09
0.00
0.00
5.08
5.43
9.54
7.88
2.98
5.69
2.10
3.06
2.10
2.45
1.14
1.84
1.66
0.00
1.40
0.96
1.23
1.14
1.14
1.05
0.88
0.00
0.79
0.70
0.70
0.35
0.26
0.09
0.09
0.26
0.18
0.00
0.18
0.18
0.18
0.18
0.00
0.00
0.00
0.00
0.09
0.09
1.3
1.0
0.0
0.0
0.0
0.0
5.0
0.0
0.0
0.0
58.3
100.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
75.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.7
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
25.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
98.1
100.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
93.8
0.0
100.0
0.0
0.0
0.0
0.0
0.0
100.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
100.0
0.0
0.0
0.0
0.0
0.0
100.0
0.0
100.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
100.0
0.0
0.0
0.0
96.1
99.0
100.0
100.0
0.0
0.0
95.0
100.0
100.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
100.0
100.0
80.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
2.0
0.0
0.0
0.0
1.9
0.0
0.0
0.0
0.0
0.0
41.7
0.0
0.0
6.3
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
20.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
100.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
23.1
0.0
0.0
0.0
18.8
0.0
0.0
0.0
7.7
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
100.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
100.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
87.8
100.0
95.4
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
27.3
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
100.0
7.7
25.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
100.0
0.0
0.0
100.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
100.0
100.0
98.2
12.2
0.0
4.6
100.0
100.0
100.0
100.0
0.0
100.0
100.0
0.0
0.0
0.0
100.0
0.0
76.9
75.0
100.0
0.0
100.0
100.0
100.0
100.0
66.7
0.0
0.0
0.0
0.0
0.0
0.0
100.0
0.0
100.0
0.0
0.0
0.0
0.0
0.0
100.0
0.0
0.0
1.8
0.0
0.0
0.0
0.0
0.0
0.0
0.0
76.9
0.0
0.0
0.0
81.3
72.7
0.0
0.0
7.7
0.0
0.0
0.0
0.0
0.0
0.0
0.0
33.3
100.0
0.0
0.0
100.0
0.0
0.0
0.0
100.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
According to an electivity index calculated for main plant species consumed
(Figure 10), there was a relatively high preference for most of the species across
both the wet and the dry seasons, with the exception of Acacia schweinfurthii
which was not selected during the wet season.
129
Wet
Dry
Trichilia
dregeana
Peltophorum
africanum
Ficus sur
Diospyros
mespiliformes
Dalbergia
armata
Celtis africana
Berchemia
zeyheri
Combined
Acacia
schweinfurthii
Electivity Index
1.0
0.8
0.6
0.4
0.2
0.0
-0.2
-0.4
-0.6
-0.8
-1.0
Plant Species
Figure 10:
Main forage plant species electivity index. Utilisation of main forage
species in relation to the availability of such, expressed as an
electivity/selectivity index for the wet season, dry season and
combined for both seasons.
For plant communities utilized, the electivity index (Figure 11) shows that there was
a distinct preference for sub-community 4.2 (Sclerocarya birrea-Panicum maximum
Woodland) in both the wet and dry seasons. Community 3 (Acacia nigrescensCombretum apiculatum Woodland) and variant 4.4.1 (Pappea capensis Variant)
were avoided during wet season.
Refer to Habitat Utilisation above for plant
community descriptions.
130
1.0
0.8
Electivity Index
0.6
0.4
0.2
Electivity-Wet
0.0
Electivity-Dry
-0.2
Electivity-Combined
-0.4
-0.6
-0.8
-1.0
2.2
3
4.1
4.2
4.3
4.4.1
Plant Community
Figure 11:
Plant community electivity index. Utilisation of plant communities in
relation to their availability expressed as an electivity/selectivity index
for the wet season, dry season and combined for both seasons.
131
Discussion
Once the property was mapped and the vervets were habituated, data collection
commenced. The study troops group composition and population density (0.4
vervets per ha) appeared within the norms, taking into consideration that their
habitat was close to optimal with very few disturbances for the study troop.
According to Pruetz & Isbell (2000), food distribution and patch size has a
correlation to agonistic behaviour, with food scarcity leading to increased agonistic
interactions. During the study period several agonistic interactions were observed,
however due to there being a constant supply of various food sources throughout
both seasons, such interactions could not be linked to food distribution or patch
size.
The study troop’s habitat was considered ‘ideal’ in terms of food and water
availability, being rich in resources compared to potential surrounding habitats.
The study troop established their territory in the centre of the ‘ideal’ habitat, with
other troops occupying territories adjacent to such. From observations of other
troops in the study area, it was clear that the study troop was a larger and more
successful troop than the others and that they were successful in the defense of
their territory. According to Brown (1982), who did most of his work on birds, one
of the main reasons a territory is defended is for its economic value. He pointed
out that there are several costs and benefits to defending a territory with its
resources. Energy expenditure and risk of injury are some of the costs. Benefits
include priority of access to resources. Territorial behaviour becomes favoured by
selection whenever the benefits outweigh the costs, making the resource
economically defendable as is the case with vervet troops (Krebs & Davies, 1999).
The idea of economic defendability has also been used to predict levels of
resource availability, which in turn could lead to territorial defense.
132
If resources are scarce or too freely available, the gains from excluding others
becomes less cost effective and not worth the effort (Krebs & Davies, 1999).
With regards to habitat utilisation, the vervets had ten communities, subcommunities and variants available to them within their home range. Of the ten
available communities, sub-communities and variants they utilized only six during
the study period i.e. sub-community 2.2 (Combretum imberbe-Acacia nigrescens
Woodland), community 3 (Acacia nigrescens-Combretum apiculatum Woodland),
sub-community 4.1 (Balanites maughamii-Panicum maximum Woodland), subcommunity 4.2 (Sclerocarya birrea-Panicum maximum Woodland), sub-community
4.3 (Combretum zeyheri-Panicum maximum Woodland), and variant 4.4.1 (Pappea
capensis Variant). Of the six communities, sub-communities and variants utilized,
sub-community 4.2 was used the most during both the wet and the dry season.
Community 3 and variant 4.4.1 were only used during the dry season, whereas the
other communities, sub-communities and variants were randomly utilized across
both seasons.
The daily ranging patterns of vervets varies according to habitat type, predator
presence, competing neighbouring troops, distribution and nature of food, access
to water and sleeping sites (Estes, 1991; Skinner & Smithers 1990; Adeyemo,
1997). Adequate vegetative cover is a prerequisite for vervet protection, feeding
and procreation, with food availability strongly influencing their daily activity
patterns regardless of season (Michael, 1983). When foraging on the ground the
vervets often disperse over quite a broad front and progress relatively slowly.
There was no statistically significant difference between distances travelled and
area covered on a daily basis during dry and wet seasons. What was noted was
that during dry periods when the vervets extended their range, they would often
spend evenings in trees close to where they were foraging. Such trees were not
their ‘usual’ sleeping sites.
133
Even though they were moving into dry season areas they never visited during the
wet season, once in such areas, daily distances travelled and area covered
remained relatively constant regardless of season. This could be attributed to the
general habitat the troop occupies and the amount of time available for traveling.
The area appears to be pristine vervet habitat with a permanent water source and
several mountain river streams with accompanying riparian vegetation. There was
an abundant supply of various food sources throughout the year, with movement
patterns mostly coinciding with the fruiting times of several tree and plant species.
There was no need for the study troop to move far from their territory and they
remained within the boundaries of such.
On average distances travelled and area covered daily were 0.2 km and 0.2 ha
further and larger respectively for the dry season. On examination of Figure 5a
and 5b it appears as though distances travelled and area covered daily are
significantly more during the dry season. However, upon further investigation of
the data, what emerges is that during wet and dry periods they still on average
travel similar distances and cover similar sized areas daily. They did extend the
boundaries of their wanderings by sleeping closer to food sites enabling them to
travel further into areas they never utilized during the dry season in search of
additional food sources (Figure 5a).
The vervets range more than doubled during the dry season, however, their daily
range was on average only 2 ha more than during the wet season. Home range
size appeared to be linked to food and particularly water availability, with the troops
mean daily distance travelled increasing slightly during the dry season. According
to Cheney (1987), home-range sizes of vervets are 0.12-1.78km2. The fact that
the study troop had a permanent water source within their home range was an
important factor affecting their ranging patterns.
134
During the dry season they frequented their water source on an almost daily basis,
this corresponds to observations of other primate species for example patas and
tantalus in the Kala Maloue National Park in northern Cameroon, who also drank
water on an almost daily basis (Nakagawa, 1999).
During the wet season longer periods of time were spent away from the permanent
water source as there was an abundant supply of ground water throughout their
home range, particularly after rain had fallen.
The vervets do not utilize their home ranges evenly, but rather tend to concentrate
on areas of abundant food supply and move through adjacent areas solely to get to
resources. Several studies have documented that primates in general utilize areas
with higher food concentrations within their home range in order to maximize food
intake relative to energy expenditure (Clutton-Brock, 1975; Harrison, 1983b;
Vedder, 1984; Barton et al., 1992; Nakagawa, 1999). During the dry season they
are not as selective as during the wet season when there is a much larger
selection of food resources. The vervets appear to have an intrinsic knowledge of
where their food sources are located (Krebs & Davies, 1999); however, it does not
appear that they know precisely when to visit some seasonal resources and they
visit some trees on a relatively regular basis as if to investigate whether such are
bearing fruit or not.
Although vervets have diverse and seasonally variable diets, and with over
seventy-five different food species being identified and consumed by the study
troop for the study period, they concentrated mostly on the plants depicted in
Figure 8.
Berchemia zeyheri and Trichilia dregeana were the most important
species during the wet season, with Diospyros mespiliformis and Ficus sur being
most important during the dry season.
The study troop’s diet consisted of a
number of staple food items with a relatively wide seasonal variation for additional
supplementation.
135
According to Lee & Hauser (1998), vervets eat in proportion to what is available
(density, size and standing crop), and do not select food based on specific
macronutrients, rather, a large proportion of the variance in their diets is merely a
simple function of numbers, size and monthly availability or standing crop of food
resources.
The proportion of a food item in the diet of the consumer depends on the
consumers’ electivity (preference for a particular food) and the availability of that
food in the environment.
According to Ivlev’s electivity index, the study troop
positively selected the majority of their main food items, which was expected. Subcommunity 4.2 was positively selected across both the wet and dry seasons.
Community 3 and variant 4.4.1 were not selected during the wet season and were
only utilized during the harsher dry season.
Remaining communities, sub-
communities and variants were utilized less extensively. Results are as expected
bearing in mind that the vervets used only small portions of what was available in
most habitats (Figure 11).
Grasses and insects were less important sources of food, with ‘tree food’ being the
mainstay of their diets. It appeared that insect meals were never planned for and
that only when the study troop by chance came a cross a termitarium with winged
allates being released, did they ‘cash in’ on the nutritious supply of protein, much to
the amusement of the juveniles and babies.
An interesting observation that Estes (1991) noted, was that vervets were able to
assist in the propagation of their favourite fruit trees. The same was observed at
the study site where areas containing large Diospyros mespiliformis trees had
several young Peltophorum africanum trees growing under them and vice versa.
136
The vervets were feeding on one tree species and during the course of their daily
wanderings visiting the other tree species where they defecated the first trees
seeds under the second tree, leading to the combination of trees growing together.
Both tree species fruited at the same time of the year. There were many other less
conspicuous tree combinations throughout their home range further supporting the
observation.
Commonly the vervets were seen turning sticks and small logs over whilst foraging
on the ground. They scratched around in leaf litter and herbivore dung in search of
insects and undigested seeds or pods.
Unlike baboons that are capable of
digging, the vervets were never seen digging - their hands did not appear tough
enough. When foraging on Diospyros mespiliformis the adults bit into the fruit and
peeled such before eating it. When fruit was taken from the ground, it was rubbed
between the hands before being consumed, this is contrary to what was observed
in the Amboseli by Struhsaker (1967b).
The majority of the study troop often only fed on one particular food item at a time,
albeit for a relatively short period of time, before switching to another food item or
moving off. Dominant animals usually orchestrated the troops feeding behaviour,
only allowing sub-ordinates to feed when they were done. However, this did not
prevent submissive animals from feeding on less preferred food items or from
foraging on the ground.
When strange or unknown food sources were
encountered, it would more often than not be the sub-adults and juveniles that
would be the first to experiment with such, and only once they seemed to approve
of it would the adults partake.
137
It was extraordinary to witness the vervets moving off in a set direction with no
apparent reason for doing so and no sign of food in the close proximity, only to be
surprised at their ability to find a food source/patch amongst what appeared to be
sterile vegetation – it was as though they had a memory of food sources and
potential times when such sources would provide food.
On several occasions
when they visited such potential sites, the trees were not yet in a position to
provide food and the vervets just moved on, signifying that they could not predict
the exact timing of trees fruiting, nevertheless they knew exactly where to go.
The vervets frequently visited sites when the fruiting times of trees at such sites
were close, until the trees provided fruit, in which case they would visit the site
regularly until its fruit was depleted.
The sophisticated knowledge that certain
species have of their environment, which includes the vervets’ ability to remember
the location of food sources, is relatively well documented (Griffin 1984). Food
patch depletion and rate of return have been investigated for various bird species
(Krebs and McCleery 1984; Kamil and Roitblat 1985; and Kamil, Krebs, and
Pulliam 1987).
Such could have relevance to vervet foraging strategies,
particularly for plant species that provide fruit at regular intervals throughout the
year for example the various Ficus sp. occurring throughout the study troops home
range.
In most other temperate sub-tropical research sites it appears as though food
variability and availability was less than at the Blydeberg study site. At Blydeberg
there was a large variety of food species to choose from, however, the study troop
did have a definite seasonal preference for particular species. This correlates with
finding by Lee & Hauser (1998) in Amboseli - Kenya, and Harrison (1984) in
Senegal, where findings suggest that vervet diets are usually restricted to a small
number of staple foods with a wider seasonal supplementation.
Foods are
consumed in proportion to their availability, with variation in diet being a simple
function of various food species available standing crop.
138
As one food species standing crop diminishes, to be cost effective in their foraging
strategies, vervets move off to find alternative species to forage on (Lee & Hauser,
1998).
According to Clutton-Brock (1977), many species of monkey including the vervet
monkey are able to recall the location and phenological patterns of food and water
within their home ranges. This appears to be the case with the study troop that
somehow knew when to visit areas not often frequented, to ‘check’ whether trees in
the area were fruiting or not. In all instances they started visiting such sites a short
period before trees started producing fruit and continued to visit until the trees were
no longer bearing fruit.
Often when the vervets were observed foraging, they were in the presence of
antelope species that moved around with them, particularly the Bushbuck
(Tragelaphus scriptus). Bushbuck foraged on leaves of broken branches and fruit
that the vervets dropped. The vervets were very wasteful feeders and dropped
large amounts of fruit when feeding. On several occasions a resident group of
Banded Mongoose (Mungos mungo) was observed traveling with the vervets, it is
not clear whether there was a feeding association or whether the arrangement was
for safety purposes, the latter seems more probable. Several bird species were
also seen feeding in the same trees as the vervets, particularly the Purplecrested
Lourie (Tauraco porphyreolophus). However, the association appeared to be of a
more competitive nature, with the lourie eating the same fruits that the vervets
were feeding on. There was also a resident troop of Baboons (Papio ursinus) that
lived in the study area and frequently their wanderings overlapped with those of the
vervets. Certain trees and the permanent water source in the area were shared by
both species. According to Estes (1991), it is common for the two species to have
overlapping territories, they do compete for resources, and in some instances the
baboon can be an occasional predator of young vervets – this behaviour was not
observed during the study period.
139
During the dry season the baboons spent most of their time in the more open
grassy areas foraging, and competition for resources with the vervets was not
noted. During the wet season when trees and shrubs were fruiting, the baboons
were often observed displacing the vervets from large trees and shrubs containing
ripe or semi ripe fruit, particularly Sclerocarya birrea, Diospyros mespiliformis and
various Grewia sp. When the vervets were feeding in a particular tree, and the
baboons arrived, the vervets would simply unobtrusively move off to another area
or just remain in the background until the baboons had finished, this sympatric
relationship has been recorded on other occasions (Zinner et al., 2001).
Several species of non-human primates are renowned for their crop raiding antics,
with the vervet being one of the main culprits (Maples et al., 1976). The problems
are however becoming more widespread, with food-raiding tactics occurring in
reserves, suburban areas, at picnic sites and at lodges. According to Saj et al.
(1999), human food is of a higher quality than the vervets natural food, having
more energy per unit and thus allowing the vervets to reach their metabolic
demands much sooner than if they were only eating their natural foods. With this
option available to vervets in certain situations, it is obvious that they would utilize
high-quality human food sources. In many situations it is no longer a matter of
choice but one of survival and the vervets have no choice but to utilize human food
sources as their natural habitats have been degraded to such an extent that they
are unable to meet their daily caloric requirements from remaining natural food
sources alone (Else, 1991).
As our knowledge about vervet’s increases, the challenge to protect them becomes
more apparent. With habitat destruction and hunting being at the forefront of all
primates’ demise, it is critical that we nurture a better understanding of, and
appreciation for all primates and the habitats they live in.
Increasing human
populations and intensified agricultural practices, particularly in riverine habitats is
likely to increase the conflict between man and vervet.
140
In Eritrea 37.2 % of all vervet records reflect them to be within 500 m of an
agricultural area, and 31.8 % were within 1000 m of the nearest village. Vervets
are considered pests and are chased and killed to such an extent that there is a
strong negative effect on the entire population in Eritrea (Zinner et al., 2002).
With vervets being seasonal breeders (Lee, 1987; Hauser & Fairbanks, 1988;
Dunbar & Barrett, 2000), it is important that the timing of births corresponds to the
fruiting of trees and the onset of the wet season.
Seasonality thus plays an
important role in vervet society and dictates their daily and monthly activity
patterns. The abundance of seasonal foraging sites and the absence of such
during the drier months make vervet movement patterns almost predictable once
their habitat and resources has been identified and mapped. Due to some areas
having been modified by man for agricultural activities, prime vervet habitat has
been destroyed, leaving the animals no choice but to raid crops, in turn leading to
them being labeled vermin under current legislation in South Africa. This status
allows farmers to shoot vervets on site without having to justify themselves. No
permits or permission is required. To vervets the benefits of crop raiding seem to
outweigh the costs, or it might be that they have not yet learnt to adapt to the ‘new’
threat of high-powered rifle wielding farmers that eliminate them from a distance.
Many farmers believe vervets to be destructive due to their wasteful feeding habits,
but such is their natural habits in a very unnatural man made environment (Dunbar
& Barrett, 2000).
Ongoing reduction of vervet habitat for agricultural purposes, with accompanying
increases in human populations in such areas leads to intensified conflict between
man and vervet, with the outcome being obvious as long as vervets are seen as
pests. This represents a real danger of extinction in the medium term to localized
vervet populations, with loss of genetic variability (Zinner et al., 2002).
141
Conflicts between non-human primates and local human populations are well
documented throughout Africa (Basckin & Krige, 1973; Kavanagh, 1978, 1980;
Skinner & Smithers 1990; Estes, 1991; Dunbar & Barrett, 2000).
Inclusion of
human food in the vervet diet impacts their activity budget and they tend to feed
and travel less, with more time being spent on other activities including resting and
socializing (Saj et al., 1999). Should the inclusion of human food be a permanent
arrangement, it is possible that the affected troop’s home range will become
smaller as they travel less. According to Saj et al. (1999) and Basckin & Krige
(1973), obvious costs associated with the inclusion of human food into a vervet diet
are increased aggression leading to injuries, and direct competition with humans.
Of interest is that adult females, particularly females with babies, spend much less
time consuming human food in comparison to other group members, except for
juveniles that spend the most time consuming human food - it has been suggested
that this is due to their more adventurous and exploratory tendencies (Saj et al.,
1999). With the study troop, as mentioned previously, often the juveniles would eat
or ‘try’ a new or novel food source through a ‘trial and error’ approach. Once the
juveniles were consuming the new food, only then would the other troop members
taste it. This behaviour suggests that troops with large proportions of juveniles
could be more likely candidates to become ‘pests’ in the future should they become
exposed to human food sources.
To prevent vervet damage to crops and lodges, and to reduce or control potentially
detrimental incidents, it is critical to develop management plans in areas where
vervets are problematic.
According to Brennan et al. (1985), the removal of
accessible sources of human food accompanied with the trapping and removal of
known offenders and excess animals will go a long way towards solving the
problem. Simply removing an entire troop will only create a vacuum for another
troop to fill and will not alleviate the problem. Management plans should include an
assessment of the situation from a distanced perspective, taking the habitat
requirements of the vervets into consideration.
142
One of the objectives of a vervet management plan should include the provision of
natural food sources which could be achieved on the medium to long term by
planting trees that provide food throughout the year. Another objective should be
the education of all humans visiting and residing or working in such areas to not
provide food or encourage the vervets to beg for food. Yet another objective could
be to ensure no food is left lying around for the vervets to notice and steal. With a
minimum amount of effort and simple logic it would be possible to manage
problematic situations involving vervets to the benefit of both man and vervet.
According to Brennan et al. (1985), removal of accessible sources of human food,
accompanied by limited trapping and removal to reduce population density with
regular follow-up studies to ensure the problem is sufficiently controlled, is the
recommended form of control for problem vervets.
Acknowledgements
Professor Duncan Mitchell is thanked for allowing the research to take place on his
privately owned portion of the Blydeberg Conservancy. The National Research
Foundation (NRF) financially supported this study.
143
References
ADEYEMO, A.I.
1997.
Diurnal activities of green monkeys Cercopithecus
aethiops in Old Oyo National Park, Nigeria. S. Afr. J. Wildl. Res, 27(1): 2426.
ALLAIN, C. & CLOITRE, M. 1991. Characterizing the lacunarity of random and
deterministic fractal sets. Physical Review, 44: 3553-3558.
ALTMANN, J.
1974.
Observational study of behaviour: sampling methods.
Behaviour, 49: 227-267.
BALDELLOU, M. & ADAN, A. 1998. Diurnal and seasonal variations in vervet
monkeys’. Psychological Reports, 83(2): 675-85.
BARBOUR, M.G., BURK, J.H. & PITTS, W.D. 1987. Terrestrial Plant Ecology. 2nd
ed. Massachusetts: The Benjamin/Cummings Publishing Company, Inc.
BARTLETT, M.S.
1978.
An introduction to the analysis of spatial patterns.
Supplement Advanced Applied Probability, 10: 1-13.
BARTON, R.A., WHITEN, A., STRUM, S.C., BYRNE, R.W. & SIMPSON, A.J.
1992. Habitat use and resource availability in baboons. Animal Behaviour,
43: 831-844.
BASCKIN, D.R. & KRIGE, P.D.
1973. Some preliminary observations on the
behaviour of an urban troop of vervet monkeys (Cercopithecus aethiops)
during the birth season. J. Behav. Sci, 1: 287-296.
144
BEZUIDENHOUT, H. 1993. Syntaxonomy and synecology of Western Transvaal
Grasslands. Ph.D. dissertation, University of Pretoria, Pretoria.
BREDENKAMP, G.J., JOUBERT, A.F. & BEZUIDENHOUT, H.
1989.
A
reconnaissance survey of the vegetation of the plains in the PotchefstroomFochville-Parys Area. South African Journal of Botany, 55: 199-206.
BREDENCAMP, G. & VAN ROOYEN, N. 1998a. Mixed Lowveld Bushveld. In:
Low, A.B. & Rebelo, A.G. (eds) Vegetation of South Africa, Lesotho and
Swaziland. 2nd ed. Dept Environmental Affairs and Tourism, Pretoria.
BREDENCAMP, G. & VAN ROOYEN, N. 1998b. Sour Lowveld Bushveld. In:
Low, A.B. & Rebelo, A.G. (eds) Vegetation of South Africa, Lesotho and
Swaziland. 2nd ed. Dept Environmental Affairs and Tourism, Pretoria.
BRENNAN, E.J., ELSE, J.G. & ALTMANN, J. 1985. Ecology and behaviour of a
pest primate: vervet monkeys in a tourist-lodge habitat. Afr. J. Ecol, 23: 3544.
BRONIKOWSKI, A.M. & ALTMANN, J. 1996. Foraging in a variable environment:
weather patterns and the behavioural ecology of baboons. Behav. Ecol.
Sociobiol, 39: 11-25.
BROWN, J.L. 1982. Optimal group size in territorial animals. J. theor. Biol., 95:
793-810.
BROWN, L.R.
1997.
A plant ecological and wildlife management plan of the
Borakalalo Nature Reserve, North-west Province.
University of Pretoria, Pretoria.
145
Ph.D.
dissertation.
BROWN, L.R. & BREDENKAMP, G.J. 1994. The phytosociology of the southern
section of the Borakalalo Nature Reserve, South Africa. Koedoe, 37: 59-72.
BRUORTON, M. R., DAVIS, C. L. & PERRIN, M.R. 1991. Gut microflora of vervet
and samango monkeys in relation to diet.
Applied and Environmental
Microbiology, 57: 573-578.
CAUGHLEY, G. & SINCLAIR, A.R.E. 1994. Wildlife Ecology and Management.
Canada: Oxford University Press.
CHENEY, D.L. 1987. Interactions and relationships between groups. In: Primate
Societies (Eds B.B. Smuts, D.L. Cheney, R.M. Seyfarth, R.W. Wrangham and
T.T. Strushaker). University of Chicago Press, Chicago.
CHENEY, D.L., LEE, P.C. & SEYFARTH, R.M. 1981. Behavioural correlates of
non-random mortality among free ranging adult female vervet monkeys.
Behav. Ecol. Sociobiol, 9: 153-161.
CHENEY, D.L., & SEYFARTH, R.M.
1987.
The influence of intergroup
competition on the survival and reproduction of female vervet monkeys.
Behav. Ecol. Sociobiol, 21: 375-386.
CHENEY, D.L., SEYFARTH, R.M., ANDELMAN, S.J. & LEE, P.C.
1988.
Reproductive success in vervet monkeys. In Reproductive success, ed. T.H.
Clutton-Brock. Chicago: University of Chicago Press.
CHENEY, D.L., & SEYFARTH, R.M. 1992. How Monkeys See the World – Inside
the Mind of Another Species. Chicago: University of Chicago Press.
146
CLUTTON-BROCK, T.H.
1975.
Ranging behaviour of red colobus (Colobus
badius tephrosceles), in the Gombe National Park. Animal Behaviour, 23:
706-722.
CLUTTON-BROCK, T.H. 1977. Some aspects of intraspecific variation in feeding
and ranging behaviour in primates. In Primate ecology: Studies of feeding
and ranging behaviour in lemurs, monkeys and apes, ed. T.H. Clutton-Brock.
London: Academic Press.
COLLINSON, R.F.H. 1985. Selecting Wildlife Census Techniques. Monograph 6.
University of Natal: Institute of Natural Resources.
CROOK, J.H. & GARTLAN, J.S. 1966. Evolution of primate societies. Nature,
210: 1200-1203.
DAVIS, J.C. 1986. Statistics and data analysis in Geology. 2nd ed. New York:
John Wiley & Sons, Inc.
DUNBAR, R. & BARRETT, L. 2000. Cousins our primate relatives. London: BBC
Worldwide Ltd.
ECKHARDT, H.C. 1993. A synecological study of the vegetation of the northeastern Orange Free State. M.Sc. thesis. University of Pretoria, Pretoria.
ELSE, J.G.
1991.
Non-human primates as pests.
In Primate Responses to
Environmental Change, ed. H.O. Box. London: Chapman and Hall.
ESTES, R.D. 1991. The Behaviour Guide to African Mammals. London: The
University of California Press.
147
GRIFFIN, D.R. 1984. Animal thinking. Cambridge, Mass.: Harvard University
Press.
HAGAN, J.E., EASTMAN, J.R. & AUBLE, J. 1998. Cartalinx the spatial data
builder – Users guide. Clark University, Worcester, USA.
HARRISON, M.J.S.
1983a. Age and sex differences in the diet and feeding
strategies of the green monkeys, Cercopithecus sabaeus. Animal Behaviour,
31: 969-977.
HARRISON, M.J.S.
1983b. Patterns of range use by the green monkey,
Cercopithecus sabaeus, at Mt. Assirik, Senegal. Folia Primatol, 41: 157-179.
HARRISON, M.J.S. 1984. Optimal foraging strategies in the diet of the green
monkeys, Cercopithecus sabaeus, at Mt. Assirik, Senegal. Int. J. Primatol, 5:
435-471.
HAUSER, M.D. & FAIRBANKS, L.A.
1988.
Mother-offspring conflict in vervet
monkeys: variation in response to ecological conditions. Animal Behaviour,
36: 802-813.
HENNEKINS, S. 1998. TURBOVEG: Clipper database management software for
storage, selection, and export of vegetation data (relevés). Netherlands.
HENZI, S.P. 1984. Some aspects of visual signaling and social organization in the
vervet monkey (Cercopithecus aethiops pygerthrus).
University of Natal Natal.
148
Ph.D. dissertation.
HILL, M.O. 1979. TWINSPAN: A Fortran program for arranging multivariate data
in an ordered two-way table by classification of individuals and attributes.
New York: Cornell University.
ISBELL, L.A., PRUETZ, J.D. & YOUNG, T.P.
1998.
Movements of vervets
(Cercopithecus aethiops) and patas monkeys (Erythrocebus patas) as
estimators of food resource size, density and distribution.
Behav.
Ecol.
Sociobiol, 42: 123-133.
KAMIL, A.C., KREBS, J.R. & PULLIAM, H.R. 1987. Foraging behaviour. New
York: Plenum Press.
KAMIL, A.C. & ROITBLAT, H.L.
1985.
The ecology of foraging behaviour:
Implications for animal learning and memory. Ann. Rev. Psych, 36: 141-169.
KAVANAGH, M. 1978. The diet and feeding behaviour of Cercopithecus aethiops
tantalus. Folia Primatol, 30: 30-63.
KAVANAGH, M. 1980. Invasion of the forest by an African savannah monkey:
behavioural adaptations. Behaviour, 73: 238-259.
KENT, M. & COKER, P. 1997. Vegetation Description and Analysis – A Practical
Approach. New York: John Wiley & Sons.
KOOIJ, M.S., BREDENKAMP, G.J. & THERON, G.K. 1990. Classification of the
vegetation of the B land type in the north-western Orange Free State. South
African Journal of Botany, 56: 309-318.
KREBS, C. J. 1989. Ecological methodology. New York: Harper and Row.
149
KREBS, J.R. & DAVIES, N.B. 1999. An Introduction to Behavioural Ecology. 3rd
ed. London: Blackwell Science Ltd.
KREBS, J.R. & MCCLEERY, R.H. 1984. Optimization in behavioural ecology. In
Behavioural ecology: An evolutionary approach, ed. J.R. Krebs and N.B.
Davies. Oxford: Blackwell Scientific.
LAWES M.J., HENZI, S.P. & PERRIN, M.R. 1990. Diet and feeding behaviour of
samango monkeys (Cercopithecus mitis labiatus) in Ngoye.
Folia
Primatologica, 54: 57-69.
LEE, P.C.
1984.
Ecological constraints on the social development of vervet
monkeys. Behaviour, 91: 245-262.
LEE, P.C. 1987. Nutrition, fertility and maternal investment in primates. Journal of
Zoology, 213: 409-422.
LEE, P.C. & HAUSER, M.D. 1995. Diet, food selection, long term habitat changes
and local extinction in vervet monkeys. Am. J. Primatol, 20: 131-132.
LEE, P.C. & HAUSER, M.D.
1998.
Long-term consequences of changes in
territory quality on feeding and reproductive strategies of vervet monkeys.
Journal of Animal Ecology, 67: 347-358.
MAPLES, W.R., MAPLES, M.K., GREENHOOD, W.F. & WALEK, M.L.
1976.
Adaptations of crop raiding baboons in Kenya. Am. J. Phys. Anthrop, 45:
309-316.
MICHAEL, J.S. 1983. Age and sex differences in the diet and feeding strategies
of the green monkeys. Anim. Beha, 31:961-977.
150
MUELLER-DOMBOIS, D. & ELLENBERG, H.
1974.
Aims and methods of
vegetation ecology. New York: Wiley & Sons.
NAGEL, U. 1973. A comparison of anubis baboons, hamadryas baboons and
their hybrids at a species border in Ethiopia. Folia Primatol. 19: 104-166.
NAKAGAWA, N.
1999.
Differential habitat utilisation by Patas monkeys
(Erythrocebus patas) and Tantalus monkeys (Cercopithecus aethiops
tantalus) living sympatrically in northern Cameroon.
American Journal of
Primatology, 49: 243-264.
NAKAGAWA, N.
2003.
Difference in food selection between patas monkeys
(Erythrocebus patas) and tantalus monkeys (Cercopithecus aethiops tantalus)
in Kala Maloue National Park, Cameroon, in relation to nutrient content.
Primates, 44: 3-11.
PRUETZ, J.L. & ISBELL, L.A. 2000. Correlations of food distribution and patch
size with agonistic interactions in female vervets (Chlorocebus aethiops) and
patas monkeys (Erythrocebus patas) living in simple habitats. Behav. Ecol.
Sociobiol, 49: 38-47.
SAJ, T., SICOTTE, P. & PATERSON, J.D.
1999.
Influence of human food
consumption on the time budget of vervets. Int. J. Primatology, 20: 977-994.
SKINNER, J.D. & SMITHERS, R.H.N.
1990.
The Mammals of the Southern
African Subregion. Pretoria: University of Pretoria.
STRUHSAKER, T.T.
1967a.
Social structure among vervet monkeys
(Cercopithecus aethiops). Behaviour, 29: 83-121.
151
STRUHSAKER, T.T.
1967b.
Behaviour of Vervet Monkeys (Cercopithecus
aethiops). Zoology, 82: 1-64.
STRUHSAKER, T.T. 1967c. Ecology of Vervet Monkeys (Cercopithecus aethiops).
Ecology, 48: 891-904.
VEDDER, A.L. 1984. Movement patterns of free-ranging mountain gorillas (Gorilla
gorilla beringei) and their relation to food availability. American Journal of
Primatology, 7: 73-88.
WHITTEN, P.L.
1988. Effects of patch quality and feeding subgroup size on
feeding success in vervet monkeys (Cercopithecus aethiops).
Behaviour,
105: 35-52.
WRANGHAM, R.W. & WATERMAN, P.G. 1981. Feeding behaviour of vervet
monkeys on Acacia tortilis and Acacia xanthophloea with special reference to
reproductive strategies and condensed tannin production. J. Anim. Ecol, 50:
715-731.
ZINNER, D., TORKLER, F. & PELÁEZ, F.
2001.
Distribution and habitat of
hamadryas baboons (Papio h. hamadryas) in Eritrea. Int. J. Primatol., 22:
397-413.
ZINNER, D., PELÁEZ, F. & TORKLER, F. 2002. Distribution and habitat of grivet
monkeys (Cercopithecus aethiops aethiops) in eastern and central Eritrea.
Afr. J. Ecol., 40: 151-158.
152
CHAPTER 7
Seasonal variation in the activity budget of a troop of vervet monkeys
(Chlorocebus aethiops) in South African Temperate Sub-tropical Bushveld
Barrett, A.S.1, Brown, L.R.1, Barrett, L.2,3 and Henzi, S.P.2,4
1. Applied Behavioural Ecology and Ecosystems Research Unit, University of
South Africa
2. Behavioural Ecology Research Group, University of KwaZulu-Natal
3. School of Biological Science, University of Liverpool
4. Department of Psychology, University of Central Lancashire.
Abstract
This report describes the activity budget of a troop of vervet monkeys (Chlorocebus
aethiops) in the Blydeberg Conservancy situated in the Northern Province of South
Africa, between 1 May 2003 and 30 April 2004, covering both a wet and a dry
season and using scan sampling methods.
The study area is broadly classified as temperate sub-tropical bushveld, having a
distinct wet and dry season with accompanying variations in temperature and day
length. The focal troop selected was a semi-habituated troop residing close to a
permanent water source adjacent to the upper reaches of a tributary feeding into
the Blyde River. The troops home range is relatively undisturbed and provides for
all their nutritional requirements without them having to travel too far a field.
153
Activities recorded included foraging, socialising, moving, travelling and resting.
The study troop was generally more active during the morning and late afternoon
than around midday when they mostly rested and socialised.
This particular study formed part of a larger study to determine the study troops
home range, habitat utilisation and food selection within the Blydeberg
Conservancy.
The specific aims of this study were to investigate the activity
budget of vervets in their natural habitat and whether such was affected by
seasonality.
On average, the study troop drank for 3 % of all observations, foraged for 39 %,
moved for 15 %, rested for 17 %, and socialised for 26 %. Results revealed that
they socialized, drank and rested more during the wet season than during the dry
season. They foraged and moved more during the dry season compared to the
wet season. Adult females socialized and foraged slightly more than males. Males
were observed resting, drinking and moving more than females.
Introduction
The time animals allocate to their various activities has an important influence on
their survival and reflects demands made on them by local environmental
conditions.
Vervets respond to climatic and resource variability in their
environments through the adjustment of their activity patterns.
This issue is
relevant to a consideration of the animal as seasonality increases because its
ecological persistence depends on the severity of the harshest time of the year,
and its coping strategies at such times. Vervets are regarded as opportunistic
omnivores and have various strategies for coping with harsh environmental
conditions during the dry winter months in temperate habitats.
154
Coping behaviour includes adjusting their behaviour to travel further in order to find
sufficient resources to meet their metabolic needs, changing their diets if
necessary, and even taking foreign human food if available (Brennan et al., 1985;
Chapman, 1985; Harrison, 1985; Oates, 1987; Adeyemo, 1997; Baldellou & Adan,
1997; Saj et al., 1999).
Existing research on vervet activity patterns in response to seasonality or
seasonally driven variations in food abundance are limited for temperate areas and
for vervets in general. Existing activity related literature includes studies on the
effects of habitat changes over time on diets and reproduction in vervet monkeys in
Kenya (Lee & Hauser, 1998), analysis of the seasonal and diurnal differences in
foraging, moving, resting and socialising of free-ranging vervet monkeys in Natal
(Baldellou & Adan, 1998), and studies of seasonal vervet activity budgets in
Nigeria, including their movements, foraging, resting, drinking and socialising
(Adeyemo, 1997).
Research on vervet time budgets with regards to their
movements, foraging, resting, socialising and sleeping was done at Windy Ridge in
South Africa (Baldellou & Adan, 1997). The distribution of food and its effects on
female relationships in vervets and patas monkeys was studied in Kenya (Pruetz &
Isbell, 2000). A study on the differences in food selection between patas monkeys
and vervets was undertaken in Cameroon (Nakagawa, 2003).
Also, the
movements of vervets and patas monkeys in relation to food abundance was
studied in Kenya (Isbell et al., 1998).
Generally vervets are known to inhabit gallery forest along water courses, being
dependent on such for their existence. The effects of seasonality and its impacts
on resource availability act as precursors to vervet activity related behaviour and
daily activity patterns. Most activity related studies suggest that vervet activity
budgets are affected by resource availability, particularly food, which in turn is
seasonally dependant in temperate areas.
155
According to Lee & Hauser (1998), in Kenya where vervets are restricted mainly to
two species of acacia trees (Acacia xanthophloea and A. tortilis), availability of food
resources is the main determinant of activity patterns, with the abundance and
location of such being critical to their survival. Also, in Kenya Isbell et al. (1998)
showed that vervet activity patterns, particularly movement patterns, were affected
by the type of food available and the palatability thereof. According to research in
Nigeria by Adeyemo (1997), food availability had a strong impact on daily activity
patterns. Brennan et al. (1985), and Saj et al. (1999) studied vervet activity in a
tourist lodge environment in Kenya, and in an agricultural environment in Uganda
respectively. Both studies revealed that vervet activity budgets changed when
human foods and the often perilous acquisition thereof became part of their diets.
The vervet monkey (Chlorocebus aethiops) is well known and well researched
throughout its range, however very little behavioural ecological research has been
done in the sub-tropical areas that constitute the southern limits of their range
(Fedigan & Fedigan; 1988). Like most mammals, vervets do not make uniform use
of their available habitats. They tend, rather, to be selective regarding habitat use
and their patterns of activity reflect this (De Moor & Steffens, 1972; Chapman,
1985; Lee & Hauser, 1998;).
In general primates have broad inter- and
intraspecific variations to their home range sizes often associated with the territorial
defense of their home ranges and accompanying territorial behaviour (CluttonBrock & Harvey, 1977; Mitani & Rodman, 1979; Cheney, 1987; Dunbar & Barrett,
2000).
An understanding of how animals divide up their activities throughout the day and
by season is important for understanding their lifestyles and indicates broadly how
they interact with their environment and invest their energy and time for survival
and reproduction (Defler, 1995).
156
Other primate studies use activity budget analysis to assist in gaining an insight
and understanding into the ecology and behaviour of the species being
investigated (Chapman, 1985; Lawes & Piper, 1992; Nakagawa, 2000; Poulsen et
al., 2001; Hill et al., 2003; Hanya, 2004; Raboy & Dietz, 2004).
Generally vervet activity patterns are related to resource availability which
fluctuates seasonally in temperate sub-tropical areas.
Seasonal fluctuations in
plant food resources which comprise the largest portion of the vervets’ diet across
both the wet and the dry season are strongly related to ambient temperatures and
changes in day length (Chapman, 1985; Harrison, 1985; Adeyemo, 1997; Dunbar
& Barrett, 2000).
In most areas where vervets occur, water availability can be a restricting factor,
forcing the vervets to remain within traveling distance of such, which in turn almost
pre-determines their activity patterns (Chapman, 1985; Harrison, 1985; Adeyemo,
1997). At Blydeberg the vervets had a permanent water supply and the habitat
surrounding the water source provided for all their nutritional requirements. Their
home range consisted of almost pristine gallery forest (when compared to
neighboring areas), and contained large specimens of fruiting trees that provided
food all year round, especially trees from the Ficus genus. Due to the nature of
their habitat the study troop did not travel as much as would be expected. During
the dry season their range was slightly extended to include areas of fruiting trees
that were further from their core area.
The overall objective of this study is to probe the consequences of increased
seasonality associated with higher latitudes by examining variation in the study
troop’s patterns of activity. This study aims to provide an insight into seasonal
vervet activity budgets in temperate sub-tropical areas.
Expectations are that
seasonality will have a significant influence on the structuring of activity patterns by
the study troop.
157
It is hoped that this study will contribute towards our understanding the impacts
that seasonal variations might have on the activity patterns of vervets, and
ultimately to our understanding of the interrelationships that exists between vervet
ecological behaviour and their seasonally driven environment in the Blydeberg
Conservancy.
The specific aims of this study were to compare vervet activity patterns across
seasons at Blydeberg, with specific emphasis on seasonal differences in diurnal
activity allocation, overall male and female activity pattern differences, and male to
female seasonal activity pattern differences. It is predicted that there will be overall
seasonal differences in the allocation of time to different activities for the study
troop and that there will be seasonally prominent diurnal variations to activity
patterns.
It is also expected that there will be noticeable seasonal variations
between male and female activity patterns for the study period due to males being
larger in size than females and requiring more nourishment leading to longer
foraging times. Male foraging time could be compensated for by their feeding on
nutritionally richer foods leading to reduced foraging bouts. Seasonal predictions
originate from the fact that rainfall and dependent resources are seasonal.
Methods
Study animals.
A troop of vervet monkeys residing within the confines of the Blydeberg
Conservancy in the Northern Province of South Africa was habituated. The troop
consisted of 33 animals (5 adult males, 8 adult females and 20 non-adults). Only
data collected for adult males and females are used in the following analyses.
158
Daily activity data collected were allocated to three time periods of four hours each
i.e. 06h00 to 10h00, 10h00 to 14h00 and 14h00 to 18h00. The study period was
split into a dry winter season (May to October) and a wet summer season
(November to April) based on rainfall figures for the study area.
Study site.
The Blydeberg Conservancy is approximately 3000 ha in size and is situated along
the great escarpment in the Northern Province of South Africa, Longitude 30° 27’ to
25° 56’ E and Latitude 24° 23’ to 24° 28’ S. Altitude ranges from 350 m to 800 m
above sea level (Bredenkamp & Van Rooyen, 1998a, 1998b). The study area
constitutes the farms Dunstable (#230) and Jongmanspruit (#234) (Figure 1).
Figure 1:
Location of the Blydeberg Conservancy within the Northern Province
of South Africa.
159
The topography of the area is mountainous in the south to flat and open in the
north. Several small mountain streams make their way from a watershed in the
Drakensberg Mountains constituting the southern boundary of the conservancy,
down into the Blyde River to the north of the conservancy. Only a few of these
streams provide water throughout the year, mostly in the form of rock pools
relatively high up in their catchments and close to their source.
The average annual rainfall for the study area, as measured by a weather station
situated on the Jongmanspruit farm for the period 05/1999 to 04/2004 was 561
mm, with a high of 953 mm and a low of 255 mm recorded in 2000 and 2002
respectively. For the period 05/1999 to 04/2004, average monthly rainfall varied
from 0.7 mm during the dry winter season (May to October) to 106 mm in the wet
30
200
180
160
140
120
100
80
60
40
20
0
Temperature ( o C)
25
20
15
10
5
0
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Rainfall (mm)
summer season (November to April) (Figure 2).
Apr
Month
Figure 2:
Avg Temp - Hoedspruit 99-04
Avg Temp - Blydeberg 99-04
Avg Rainfall - Hoedspruit 99-04
Avg Rainfall - Blydegerg 99-04
Rainfall and temperature summary for the study period.
For the larger Hoedspruit region, average annual rainfall for the period 05/1999 to
04/2004 was 900 mm with a high of 1463 mm and a low of 629 mm recorded in
2000 and 2002 respectively.
160
For the period 05/1999 to 04/2004, average monthly rainfall varied from 2 mm
during the dry winter season (May to October) to 189 mm in the wet summer
season (November to April) (Figure 2).
Rainfall recorded for the study area is less than for the larger Hoedspruit region
due to the study areas location on the foothills of the Drakensberg Mountains along
the great escarpment. The mountains form a barrier leading to a rain shadow
which could be responsible for less rain in the study area; however, the mountains
do function as an important catchment for the study area and are the source of
several small mountain streams (Van Zyl, 2003). Locally thunderstorms and fog
are the main sources of precipitation.
Average annual temperature for the study area for the period 05/1999 to 04/2004
was 22 oC, with mean temperatures varying from 17 oC during the dry winter
season to 26 oC in the wet summer season (Figure 2). A minimum temperature of
3 oC and a maximum of 42 oC were recorded in the 05/2003 to 04/2004 period.
Average annual temperature for the larger Hoedspruit region for the period
05/1999 to 04/2004 was 17 oC, with mean temperatures varying from 11 oC during
the dry winter season to 23 oC in the wet summer season (Figure 2). A minimum
temperature of 11 oC and a maximum of 23 oC were recorded in the 05/2003 to
04/2004 period.
Temperatures for the study area are higher than those for the larger Hoedspruit
region due to the study area lying along the north facing foot slopes of the
Drakensberg Mountains along the great escarpment. The study area has more
direct exposure to sunlight and is more sheltered from southerly winds than the
surrounding areas (Tyson & Preston-Whyte, 2000).
161
Data collection.
The troop was followed on foot from a distance of 5-15 m for as long as possible
on each day of data collection. Data were collected over an average of eleven
days a month for a twelve-month period, resulting in 132 days of data, 30 of which
were from dawn to dusk, the rest being dependent on when and how long the troop
was located for. Data were recorded using a PALM HANDSPRINGTM data-logger,
pre-loaded with PENDRAGON FORMSTM software.
Scan samples were taken
approximately every thirty minutes from all visible animals (Altmann, 1974). Five
mutually exclusive categories of activity were recognized: foraging (feeding,
actively searching for or processing food), socializing (playing, aggression,
grooming, maternal/paternal, mating), moving, resting and drinking.
Troop
members were categorised into various age and sex classes i.e. Adult Male, Adult
Female, Sub-adult, Juvenile and Neonate.
A total of 4504 individual scans were collected of which 2243 were of adult
animals. Only adult activity budgets are considered in the analyses that follow.
Statistical analysis.
SPSSTM (version 11.5.0) was used for all statistical analyses. All tests were twotailed with alpha set at 0.05.
162
Results
Overall activity budget and seasonal comparisons.
The allocations by adult subjects to the five activity categories over the entire study
period are provided in Figure 3.
SOCIALISING
26%
DRINKING
3%
FORAGING
39%
RESTING
17%
MOVING
15%
Figure 3:
Percentage of total time allocated to various activities.
Seasonal comparisons reveal no differences in the allocation of time to the
different activities (Chi-sq = 8.49, 4 df, P<0.05).
Figure 4 shows the percentage of time allocated to different activities for both wet
and dry seasons.
163
% Contribution
50.0
40.0
30.0
20.0
10.0
0.0
DRINKING
FORAGING
MOVING
RESTING
SOCIALISIN
G
Dry
1.9
41.7
14.8
16.3
25.4
Wet
3.5
38.0
14.4
17.1
27.0
Activity Type
Figure 4:
Seasonal activity breakdown.
Overall comparison of male and female activity budgets.
Male to female comparisons reveal that there were differences in the allocation of
time to the different activities (Chi-sq = 51.10, 4 df, P>0.05).
Time allocated to different activities by adult females and males over the entire
study period are provided in Figure 5.
164
% Contribution
50
40
30
20
10
0
Drinking
Foraging
Moving
Resting
Socialising
Adult Female
2.3
40.1
12.7
13.1
31.7
Adult Male
3.0
39.6
16.5
20.4
20.5
Activity type
Figure 5:
Activity breakdown by sex.
Diurnal activity budget comparisons by season.
Diurnal activity comparisons by season show that there were differences in diurnal
allocation of activities across seasons (Chi-sq = 14.95, 2 df, P>0.05).
Diurnal activity pattern comparisons across seasons are depicted in Figure 6.
165
% Contribution
10
5
0
06h00-10h00
10h00-14h00
14h00-18h00
Time of day
Dry %'s
Wet %'s
a)
60
% Contribution
50
40
30
20
10
0
06h00-10h00
10h00-14h00
Time of day
Dry %'s
b)
166
Wet %'s
14h00-18h00
% Contribution
20
15
10
5
0
06h00-10h00
10h00-14h00
14h00-18h00
Time of day
Dry %'s
Wet %'s
c)
30
% Contribution
25
20
15
10
5
0
06h00-10h00
10h00-14h00
Time of day
Dry %'s
d)
167
Wet %'s
14h00-18h00
35
% Contribution
30
25
20
15
10
5
0
06h00-10h00
10h00-14h00
14h00-18h00
Time of day
Dry %'s
Wet %'s
e)
Figure 6:
Diurnal comparison of a) drinking across seasons, b) foraging across
seasons, c) movement across seasons, d) resting across seasons,
and e) socializing across seasons..
168
Discussion
Vervet monkeys are markedly active animals, spending large amounts of time
foraging, travelling or socialising throughout the day, regardless of season
(Chapman, 1985; Harrison, 1985; Adeyemo, 1997; Dunbar & Barrett, 2000).
Thermoregulatory mechanisms have a strong influence on a number of primate
activities, particularly during the colder winter months when day length is shorter
and temperatures are lower (Chapman, 1985; Lawes & Piper, 1992; Poulsen et al.,
2001; Hill et al., 2003). Seasonal variations in day length may limit vervet activity
patterns, reducing the amount of time available to procure sufficient food during an
already stressful dry winter season.
At such times climatic conditions place
additional metabolic demands on species in order for them to survive. More time
and energy is required for foraging in order to maintain homeostasis.
Energy
requirements increase during a time when resources are already constrained,
making daily existence in harsh environments all the more difficult.
Daily activity patterns of most primates are dependent on habitat type, availability
of food resources, water accessibility and seasonality (Adeyemo, 1997).
Numerous field studies have shown that activity budgets vary in response to
changes in a number of environmental factors, including distribution and
abundance of food sources (Milton, 1980; Rylands, 1982; Oates, 1987; Peres,
1993). In some instances when there is an increase in food abundance, more time
is allocated to moving and foraging (Smith, 1977; Milton, 1980).
This is
presumably to obtain better quality food from a now larger variety of available
resources. According to Dawson (1979), vervets need to drink and rest for set
periods of time during the day in order to maintain a normal metabolic equilibrium.
For vervets to survive within their often harsh environments, it is crucial that food
eaten is assimilated into their bodies as optimally as possible to produce energy for
basic body functions.
169
Due to the diverse nature of their diets, vervets need to drink and rest to assist in
the breakdown of often complex food items for incorporation into body tissues for
the maintenance of basal metabolic rates and ongoing existence.
Also, with
vervets being social animals they need to spend time together as a group
reinforcing social bonds - resting time permits for this.
Food availability influenced the overall daily activity patterns of the study troop
during both the wet and the dry season.
Ranging patterns appeared to be
influenced by seasonal resource acquisition which is common for primates
inhabiting temperate sub-tropical areas (Bercovitch, 1983; Chapman, 1985;
Harrison, 1985; Lawes & Piper, 1992; Swart & Lawes, 1996; Baldellou & Adan,
1997; Hill et al., 2003) and most tropical forests that exhibit distinct dry and wet
seasons (Terborgh, 1986; Remis, 1997; Tutin et al., 1997; Passamani, 1998;
Hanya, 2004; Raboy & Dietz, 2004).
Activity patterns for the study group depicted as total observations for the study
period showed that the largest portion of the vervets daytime activities were
allocated to foraging (39 %), followed by socialising (26 %), resting (17 %), moving
(15 %), and drinking (3 %) (Figure 3).
Seasonal comparisons of overall vervet activity patterns at Blydeberg reveal no
significant differences in the allocation of time to the various activities monitored.
Seasonal activity patterns are expected to vary according to the availability in time
and space of the resources in an area (Clutton-Brock & Harvey, 1977; Mitani &
Rodman, 1979; Rylands, 1982; Chapman, 1985; Oates, 1987; Remis, 1997; Tutin
et al., 1997). At Blydeberg the study troop’s home range contained a permanent
water source and a large variety of different food species that contributed to their
not having to move as much as would be expected, compared to vervets living in
areas with more limited resources.
170
The effects of seasonality at Blydeberg were not as pronounced due to the general
habitat structure providing for all the vervets nutritional needs.
Percentage contributions of each activity type to the dry and wet seasons are
depicted in Figure 4. The study troop spent more time foraging during the dry
season than during the wet season, this could be related to nutritive quality of
certain food resources dropping during the dry season forcing them to consume
more to meet their daily energy requirements. They spent more time socialising
during the wet season, possibly related to resource availability with more and a
larger variety of resources being more freely available, and being less distributed
during the wet season compared to the dry season.
This made resource
acquisition easier and freed up more time for activities like socialising.
More time was spent resting during the wet season than during the dry season, this
could also be attributable to resources being more readily available, not requiring
them to travel longer distances to meet their daily metabolic requirements. Slightly
more time was spent moving during the dry season than during the wet season due to food resources not being as freely available during the dry season and
being more distributed i.e. a lesser variety of resources was available compared to
the wet season when more plants were available to forage on.
Dry season
resources were further apart compared to the wet season when several resources
in relatively close proximity provided food. Fewer insects and other alternative
resources were available during the dry season and reductions in resources led to
the vervets travelling slightly further a field in order to meet their daily dietary
requirements. More time was spent drinking during the wet season than during the
dry season, probably due to water being more freely available throughout their
home range, particularly after rain.
171
Comparisons of male and female activity patterns for the study period indicate that
there were significant differences in time allocated to various activities.
Males
moved, rested and drank more than females (Figure 5). Females foraged and
socialised more than males (Figure 5). It was expected that males would forage
more than females due to the relative size difference between the sexes, but such
was not the case and foraging time was similar. This could be due to the high
quality of foods being eaten which is linked to a larger variety of edible species
occurring within the study troops’ home range.
Diurnal activity pattern comparisons across seasons show that there were marked
activity differences for diurnal breakdowns.
Seasonal comparisons of daily
activities for the three time periods 06h00-10h00, 10h00-14h00, and 14h00-18h00
are depicted in Figure 6. According to Figure 6 the study troop drank more during
the wet season. Drinking took place mostly during midday and the late afternoon.
When more surface water was available during the wet season the vervets took
advantage of such. Foraging increased during the dry season, especially in the
afternoons. A general drop in the nutritive quality of food resources during the dry
season could be the reason for increased foraging. The study troop travelled more
in the mornings during the dry season, and more in the afternoons during the wet
season.
Dry season morning movements were to locate food.
Resting and
socializing occurred more frequently during the wet season, with socializing taking
place more frequently in the early mornings and late afternoons. With more food
being available and daily energy requirements being met faster during times of
greater food abundance, additional time became available during the wet season
for resting and socializing.
The overall percentage of time allocated to various activities has been tabulated for
comparison with similar activity related studies on vervets (Table 1).
172
Table 1:
Percentage of time allocated to various activities for different vervet
activity related studies.
Percentage of time allocated to various activities
Study location Foraging Resting Moving Socialising Drinking References
Current study
Blydeberg South Africa
39
17
15
26
3
Baldellou &
Windy Ridge South Africa
35
38
19
8
n/a
Entebbe Uganda
24
44
14
11
n/a
(1999)
Brennan et al.
20
43
16
20
n/a
(1985)
40
32
25
5
n/a
Lee (1981)
Old Oyo National
Park - Nigeria
Adan (1997)
Saj et al.
Amboseli - Kenya
Amboseli - Kenya
(2005)
Adeyemo
32
10
30
8
20
(1996)
According to Table 1, the Blydeberg results are most consistent with results from
the study undertaken in Amboseli Kenya (Brennan et al., 1985), with the exception
of resting which was much higher for the Amboseli study, possibly due to the
Amboseli troop being accustomed to food handouts and food raiding behaviour.
Marked foraging differences for some comparisons could be due to habitat
structure and an accompanying increased variety of food resources being available
to select from at Blydeberg. The overall seasonal tendency for each activity was
for the most part in line with other studies on primates in general (Bercovitch, 1983;
Harrison, 1985; Lawes & Piper, 1992; Defler, 1995; Adeyemo, 1997; Baldellou &
Adan, 1997; Passamani, 1998; Hill et al., 2003; Hanya, 2004).
Other influences to the study troop’s daily activity patterns were the proximity of
adjacent vervet troops and the movements of a baboon troop (Papio hamadryas
ursinus) that shared portions of the study troop’s home range with them.
173
Other studies also report sympatric relationships between vervets and other
primate species (Nagel, 1973; Dunbar & Dunbar, 1974; Zinner et al., 2002). When
neighbouring vervet troops were encountered, the study troop spent much of their
time vocalising, observing and sometimes even displaying antagonistic behaviour
towards members of the other troop. Their reactions to the baboons was either to
move off into the surrounding vegetation and to wait patiently for the baboons to
leave, or to leave the area moving off in an alternative direction to that of the
baboons – no direct encounters with baboons were observed during the study
period.
At the onset of this study it was expected that seasonality would significantly
impact vervet activity patterns at Blydeberg. Such was not the case and no clear
cut significant seasonal differences to the study troops overall activity patterns
were observed. The lack of significant seasonal activity variations could partly be
attributed to the study area within Blydeberg providing an almost sheltered habitat
for the study troop, with all their needs being provided for in a relatively stable and
mostly constant environment.
The study troop’s home range consisted of a
sheltered kloof with a permanent water source and gallery forest containing several
tree species that provided food throughout the year. Adjacent habitats that do not
have permanent water sources and protected kloofs should show more severe
seasonal impacts, and comparative research in such areas could be undertaken to
substantiate that the study troops habitat is superior and less prone to seasonal
fluctuations. In areas where food is patchy, scarce or clumped, primate groups
have been recorded to travel farther a field and to feed for longer periods of time
(Chapman, 1988; Overdorff, 1996). Many cercopithecines are able to change their
diets to include ‘fall back’ foods when preferred high quality foods become
seasonally scarce (Clutton-Brock & Harvey, 1977; Mitani & Rodman, 1979; Oates,
1987; Nakagawa, 1989; Strier, 1999). Availability of surface water is a key factor in
determining primate ranging patterns and has an impact on vervet activity patterns
(Barton et al., 1992; Hill et al., 2003).
174
What this study revealed, was that if vervets live in an area of increased relative
food abundance such as Blydeberg, that the impacts of seasonality are buffered
and seasonal variations to activity budgets are less prominent. By living in an
environment containing a large variety of food resources to choose from, enables
the study troop to selectively choose food items with a high nutritive value which in
turn impacts on their daily metabolic needs and related activity patterns.
This
leads to the study troops’ activity patterns not adhering to the norms of vervets
living in habitats that are restricted in terms of food abundance and variability.
Variations in activity patterns across seasons should be more apparent in areas
where the environment is harsher.
It is envisaged that when conditions at
Blydeberg become more extreme, that the study troop will react accordingly by
adjusting their behaviour to ensure their survival.
Acknowledgements
The National Research Foundation (NRF) financially supported this study.
Professor Duncan Mitchell is thanked for allowing the research to take place on his
privately owned portion of the Blydeberg Conservancy. Professor Peter Henzi and
Doctor Louise Barrett are thanked for their support and ongoing assistance and
comments.
175
References
ADEYEMO, A.I.
1997.
Diurnal activities of green monkeys Cercopithecus
aethiops in Old Oyo National Park, Nigeria. S. Afr. J. Wildl. Res, 27(1): 2426.
ALTMANN, J.
1974.
Observational study of behaviour: sampling methods.
Behaviour, 49: 227-267.
BALDELLOU, M. & ADAN, A.
1997.
Time, gender and seasonality in vervet
activity: a chronobiological approach. Primates, 38: 31-43.
BALDELLOU, M. & ADAN, A. 1998. Diurnal and seasonal variations in vervet
monkeys' activity. Psychological Reports, 83(2): 675-685.
BARBOUR, M.G., BURK, J.H. & PITTS, W.D. 1987. Terrestrial Plant Ecology. 2nd
ed. Massachusetts: The Benjamin/Cummings Publishing Company, Inc.
BARTON R.A., WHITEN, A., STRUM, S.C., BYRNE, R.W. & SIMPSON, A.J.
1992. Habitat use and resource availability in baboons. Animal Behaviour,
43: 831-844.
BERCOVITCH, F.B. 1983. Time budgets and consortships in olive baboons Papio
anubis. Folia Primatology, 41: 180-190.
BEZUIDENHOUT, H. 1993. Syntaxonomy and synecology of Western Transvaal
Grasslands. Ph.D. dissertation, University of Pretoria, Pretoria.
176
BREDENKAMP, G.J., JOUBERT, A.F. & BEZUIDENHOUT, H.
1989.
A
reconnaissance survey of the vegetation of the plains in the PotchefstroomFochville-Parys Area. South African Journal of Botany, 55: 199-206.
BREDENCAMP, G. & VAN ROOYEN, N. 1998a. Mixed Lowveld Bushveld. In:
Low, A.B. & Rebelo, A.G. (eds) Vegetation of South Africa, Lesotho and
Swaziland. 2nd ed. Dept Environmental Affairs and Tourism, Pretoria.
BREDENCAMP, G. & VAN ROOYEN, N. 1998b. Sour Lowveld Bushveld. In:
Low, A.B. & Rebelo, A.G. (eds) Vegetation of South Africa, Lesotho and
Swaziland. 2nd ed. Dept Environmental Affairs and Tourism, Pretoria.
BRENNAN, E.J., ELSE, J.G. & ALTMANN, J. 1985. Ecology and behaviour of a
pest primate: vervet monkeys in a tourist-lodge habitat. African Journal of
Ecology, 23: 35-44.
BROWN, L.R.
1997.
A plant ecological and wildlife management plan of the
Borakalalo Nature Reserve, North-west Province.
Ph.D.
Dissertation.
University of Pretoria, Pretoria.
BROWN, L.R. & BREDENKAMP, G.J. 1994. The phytosociology of the southern
section of the Borakalalo Nature Reserve, South Africa. Koedoe, 37: 59-72.
CHAPMAN, C. 1985. The influence of habitat on behaviour in a group of St. Kitts
green monkeys. Journal of Zoology, 206: 311-320.
CHAPMAN, C.A. 1988. Patch depletion by the spider and howling monkeys of
Santa Rosa National Park, Costa Rica. Behaviour, 105: 99-116.
177
CHENEY, D.L. 1987. Interactions and relationships between groups. In Smuts,
B.B., Cheney, D.L., Seyfarth, R.M., Wrangham, R.W. & Struhsaker, T.T.,
editors. Primate societies. Chicago: University of Chicago Press. p 267281.
CLUTTON-BROCK, T.H. & HARVEY, P.H. 1977. Primate ecology and social
organization. Journal of Zoology, 183: 1-39.
DAWSON, G.S. 1979. The use of time and space by the Panamanian tamarin
Saguinus Oedipus. Folia primatol, 31: 253-283.
DE MOOR, P.P. & STEFFENS, F.E. 1972. The movements of vervet monkeys
(Cercopithecus aethiops) within their ranges as revealed by radio tracking.
Journal of Animal Ecology, 41(3): 677-687.
DEFLER, T.R.
1995.
The time budget of a Group of Wild Woolly Monkeys
(Lagothrix lagotricha). International Journal of Primatology, 16: 107–120.
DUNBAR, R. & BARRETT, L. 2000. Cousins our primate relatives. London: BBC
Worldwide Ltd.
DUNBAR, R.I.M. & DUNBAR, E.P.
1974.
Ecological relations and niche
separation between sympatric terrestrial primates in Ethiopia. Folia Primatol,
21: 36-60.
ECKHARDT, H.C. 1993. A synecological study of the vegetation of the northeastern Orange Free State. M.Sc. thesis. University of Pretoria, Pretoria.
178
FEDIGAN, L.F. & FEDIGAN, L.M. 1988. Cercopithecus aethiops: a review of field
studies. In Gautier-Hion, A., Bourlièr, F., Gautier, J.P. & Kingdon, J., editors.
Primate radiation. Cambridge: Cambridge University Press.
HAGAN, J.E., EASTMAN, J.R. & AUBLE, J. 1998. Cartalinx the spatial data
builder – Users guide. Clark University, Worcester, USA.
HANYA, G.
2004.
Seasonal Variations in the Activity Budget of Japanese
Macaques in the Coniferous Forest of Yakushima: Effects of Food and
Temperature. American Journal of Primatology, 63: 165–177.
HARRISON, M.J.S.
1985.
Time budget of the green monkey, Cercopithecus
sabaeus: some optimal strategies. International Journal of Primatology, 6:
351–376.
HENNEKINS, S. 1998. TURBOVEG: Clipper database management software for
storage, selection, and export of vegetation data (relevés). Netherlands.
HILL, M.O. 1979. TWINSPAN: A FORTRAN program for arranging multivariate
data in an ordered two-way table by classification of individuals and
attributes. New York: Cornell University.
HILL, R.A., BARRETT, L., GAYNOR, D., WEINGRILL, T., DIXON, P., PAYNE, H.
& HENZI, S.P. 2003. Day length, latitude and behavioural (in) flexibility in
baboons (Papio cynocephalus ursinus). Behav. Ecol. Sociobiol, 53: 278-286.
ISBELL, L.A., PRUETZ, J.D. & YOUNG, T.P.
1998.
Movements of vervets
(Cercopithecus aethiops) and patas monkeys (Erythrocebus patas) as
estimators of food resource size, density, and distribution.
Sociobiol, 42: 123-133.
179
Behav. Ecol.
KENT, M. & COKER, P. 1997. Vegetation Description and Analysis – A Practical
Approach. New York: John Wiley & Sons.
KOOIJ, M.S., BREDENKAMP, G.J. & THERON, G.K. 1990. Classification of the
vegetation of the B land type in the north-western Orange Free State. South
African Journal of Botany, 56: 309-318.
LAWES, M.J. & PIPER, S.E. 1992. Activity patterns in free-ranging samango
monkeys (Cercopithecus mitis erythrarchus Peters, 1852) at the southern
range limit. Folia Primatology, 59: 186-202.
LEE, P.C. & HAUSER, M.D.
1998.
Long-term consequences of changes in
territory quality on feeding and reproductive strategies of vervet monkeys.
Journal of Animal Ecology, 67: 347-358.
MILTON, K.
1980.
The foraging strategy of Howler Monkeys.
New York,
Columbia University Press.
MITANI, J.C. & RODMAN, P.S. 1979. Territoriality: the relation of ranging pattern
and home range size to defendability, with an analysis of territoriality among
primate species. Behavioural Ecology and Sociobiology, 5: 241-251.
MUELLER-DOMBOIS, D. & ELLENBERG, H.
1974.
Aims and methods of
vegetation ecology. New York: Wiley & Sons.
NAGEL, U. 1973. A comparison of anubis baboons, hamadryas baboons, and
their hybrids at a species border in Ethiopia. Folia Primatol, 27: 85-107.
NAKAGAWA, N.
1989.
Feeding strategies of Japanese monkeys against
deterioration of habitat quality. Primates, 30: 1-16.
180
NAKAGAWA, N.
2000.
Foraging Energetics in Patas Monkeys (Erythrocebus
patas) and Tantalus Monkeys (Cercopithecus aethiops tantalus): Implications
for Reproductive Seasonality. American Journal of Primatology, 52: 169–185.
NAKAGAWA, N.
2003.
Difference in food selection between patas monkeys
(Erythrocebus patas) and tantalus monkeys (Cercopithecus aethiops tantalus)
in Kala Maloue National Park, Cameroon, in relation to nutrient content.
Primates, 44: 3-11.
OATES, J.F. 1987. Food distribution and foraging behaviour. Pp. 197–209 in
PRIMATE SOCIETIES.
B.B. Smuts; D.L. Cheney; R.M. Seyfarth; T.
Struhsaker; R.W. Wrangham, eds. Chicago, University of Chicago Press.
OVERDORFF, D.J. 1996. Ecological correlates to activity and habitat use of two
prosimian primates: Eulemur rubriventer and Eulemur fulvus rufus in
Madagascar. American Journal of Primatology, 40: 327-342.
PASSAMANI, M.
1998.
Activity Budget of Geoffroy’s Marmoset (Callithrix
geoffroyi) in an Atlantic Forest in Southeastern Brazil. American Journal of
Primatology, 46: 333-340.
PERES, C.A. 1993. Diet and feeding ecology of saddleback (Saguinus fuscicollis)
and moustached (S. mystax) tamarins in an Amazonian terra firma forest.
Journal of Zoology, 230: 567–592.
POULSEN, J.R., CLARK, C.J. & SMITH, T.B. 2001. Seasonal variation in the
feeding ecology of the Grey-Cheeked Mangabey (Lophocebus albigena) in
Cameroon. American Journal of Primatology, 54: 91-105.
181
PRUETZ, J.D. & ISBELL, A.I. 2000. Correlations of food distribution and patch
size with agonistic interactions in female vervets (Chlorocebus aethiops) and
pata monkeys (Erythrocebus patas) living in simple habitats.
Behavioural
Ecology and Sociobiology, 49: 38-47.
RABOY, B.E. & DIETZ, J.M.
2004.
Diet, foraging, and use of space in wild
Golden-Headed Lion Tamarins. American Journal of Primatology, 63: 1–15.
REMIS, M.J. 1997. Western lowland gorillas (Gorilla gorilla gorilla) as seasonal
frugivores: use of variable resources. American Journal of Primatology, 43:
87–109.
RYLANDS, A.B. 1982. The behaviour and ecology of three species of marmosets
and tamarins (CALLITRICHIDAE, primates) in Brazil. PhD thesis, University
of Cambridge, Cambridge, UK.
SAJ, T., SICOTTE, P. & PATERSON, J.D.
1999.
consumption on the time budgets of vervets.
Influence of human food
International Journal of
Primatology, 20(6): 977-994.
SMITH, C.C. 1977. Feeding behaviour and social organisation in howler monkey.
Pp. 97–126 in PRIMATE ECOLOGY.
T.H. Clutton-Brock ed.
London,
Academic Press.
STRIER, K.B. 1999. Primate behavioural ecology. Needham Heights, MA: Allyn
& Bacon.
SWART, J. & LAWES, M.J. 1996. The effect of habitat patch connectivity on
samango
monkey
(Cercopithecus
Ecological Modelling, 93: 57-74.
182
mitis)
metapopulation
persistence.
TERBORGH, J. 1986. Community aspects of frugivory in tropical forests. In:
Estrada A., Flemming T.H., editors.
Frugivores and seed dispersal.
Dordrecht: D.W. Junk Publishers. p 371-384.
TUTIN, C.E.G., HAM, R.M., WHITE, L.J.T. & HARRISON, M.J.S.
1997.
The
primate community of the Lopé Reserve, Gabon: diets, responses to fruit
scarcity, and effects on biomass. American Journal of Primatology, 42: 1–24.
TYSON, P.D. & PRESTON-WHYTE, R.A. 2000. The Weather and Climate of
Southern Africa. Cape Town: Oxford University Press.
VAN ZYL, D.
2003.
South African Weather and Atmospheric Phenomena.
Pretoria: Briza Publications.
ZINNER, D., PELÁEZ, F. & TORKLER, F. 2002. Distribution and habitat of grivet
monkeys (Cercopithecus aethiops aethiops) in eastern and central Eritrea.
African Journal of Ecology, 40: 151-158.
183
CHAPTER 8
GENERAL DISCUSSION AND CONSERVATION ISSUES
Each respective data chapter (chapters 5, 6 and 7) has its own discussion which
should be examined with this section in order to provide a more comprehensive
view of the specific chapters’ findings without having to repeat what has already
been stated. Various statistical analyses were performed on sampled data, the
results of which are also presented in the respective data chapters. Following is a
summary of the main data chapters with an overview of results obtained. Damage
caused by vervets and measures of reducing such are commented on.
Chapter 5, the vegetation analysis of the study area provided an insight into the
areas phytosociology, with the subsequently generated vegetation map forming the
basis of the study and providing a starting point for any subsequent studies. An
understanding of the various plant communities with their associated habitats is
fundamentally important for creating sound management and conservation
strategies, providing a base dataset for the study area.
Seasonal habitat utilisation and food selection analysis (chapter 6), indicated that
the study troop do not uniformly utilise their home range, rather, it appears as
though they tend to concentrate on areas of abundant food supply and move
through adjacent areas to get to resources. They forage mostly on a number of
staple food items, with a relatively wide seasonal variation for additional
supplementation. There is a seasonal preference for various plant communities
based mainly on resource availability in such communities. A map of the study
troops seasonal ranges, as well as an overall home range map was created.
Dietary preferences for both the wet and dry seasons was determined and
compared, revealing forage species availability and selection by the study troop.
184
Cumulative plant species contributions to the study troops diet was determined and
presented graphically and in tabular format. Electivity indices were generated for
the main plant species consumed and for plant communities utilised. Electivity
indices revealed that the vervets do have specific preferences for certain species
and communities based on seasonal availability.
An examination of the study troop’s activity patterns was undertaken to probe the
consequences of increased seasonality associated with higher latitudes (chapter
7). The specific aims of chapter 7 were to compare vervet activity patterns across
seasons at Blydeberg, with emphasis on seasonal differences in diurnal activity
allocation, overall male and female activity pattern differences, and male to female
seasonal activity pattern differences.
Findings reveal that food availability
influenced the overall daily activity patterns of the study troop during both the wet
and the dry season.
Seasonal comparisons of overall vervet activity patterns
showed no significant differences in the allocation of time to the various activities
monitored. Overall and seasonal comparisons of male and female activity patterns
exhibit no marked differences in time allocated to the various activities for the study
period. Activity breakdown for adult female and adult male vervets showed that
females foraged and socialised more than males. Males rested, drank and moved
more than females.
Diurnal activity allocation comparisons across seasons
revealed significant seasonal differences for diurnal breakdowns.
Plant communities identified and described in this study form part of the study area
containing the study troop’s home range, providing detailed data on various plant
species as well as habitats occurring within their home range. This information
combined with the study troops utilisation thereof is valuable for future planning.
Without the classification and delineation of the different plant communities, food
availability and utilisation in such communities by the vervets could not have been
determined.
185
Having determined what was available to the study troop in terms of resources, the
next logical step was to determine their utilisation thereof and then finally to
determine the impacts that seasonal variations in their habitat would have on their
overall and diurnal activity patterns. With regards to habitat utilisation, the vervets
had ten plant communities, sub-communities and variants available to them within
their home range. Of the ten available plant communities, sub-communities and
variants, they utilized only six during the study period i.e. sub-community 2.2
(Combretum imberbe-Acacia nigrescens Woodland), community 3 (Acacia
nigrescens-Combretum apiculatum Woodland), sub-community 4.1 (Balanites
maughamii-Panicum maximum Woodland), sub-community 4.2 (Sclerocarya
birrea-Panicum maximum Woodland), sub-community 4.3 (Combretum zeyheriPanicum
maximum
Variant)(Barrett, 2005).
Woodland),
and
variant
4.4.1
(Pappea
capensis
Of the six plant communities, sub-communities and
variants utilized, sub-community 4.2 was used the most during both the wet and
the dry season. Community 3 and variant 4.4.1 were only used during the dry
season, whereas, the other communities, sub-communities and variants were
randomly utilized across both seasons.
As mentioned previously, no overall
seasonal differences to activity patterns for the study troop were observed. This
indicated that their habitat and the utilisation thereof was efficient compared to
other sites where seasonal changes in habitat structure and resource availability
led to changes in activity patterns.
The impacts of seasonality were not as prominent as predicted, based on previous
studies on vervet avtivity patterns and the impacts that seasonality had on such.
What became apparent through the current study, was that relative food
abundance and availabiliy had an impact on vervet activity patterns.
186
With Blydeberg affording a habitat for the study troop that provided a large variety
and abundance of food resources regardless of season, the study troops’ seasonal
activity comparisons revealed activity patterns not adhering to the norms for
vervets living in habitats that are restricted in terms of food abundance and
variability. It is expected that variations in activity patterns across seasons should
be more apparent in areas where the environment is harsher.
From the current study it is evident that vervets are very successful at exploiting
temperate sub-tropical habitats, having adapted well to the impacts of alternative
wet and dry seasons by adjusting their behaviour accordingly. Vervets have very
flexible ecological requirements and their overall range, with the exception of more
arid areas, appears to be suitable to their continued existence.
There are no formal management plans for vervet monkeys, this is most probably
attributed to the limited knowledge available on vervets and their habitat utilisation.
It is vital to understand that no animal is actually a problem, they become problems
when man encroaches on their natural environments or when man interferes with
the normal running of events.
In agricultural and farming areas, one of the most common complaints is that
vervet monkeys destroy crops, however on closer inspection, it has been found
that:
•
Crops like the Avocado, Mango and Banana are usually picked when they
are still very green and vervets seldom if ever eat off these crops when they
are in that stage. When these crops have been eaten by vervets it is either
because they have ripened early on the tree, have been stung by some
insect or when they have a burn spot. In all of the aforementioned instances
the fruit is useless to the farmer anyway.
187
•
Within orchards there are also abundant insects, spiders, lizards, fungus
and various insect larvae and eggs which vervets consume. While more
than often assisting the farmer to control these other potential problems, the
•
vervet is wrongly accused of damaging crops.
Crops such as Litchi, Macadamia and most vegetable crops stand the
highest risk of vervet damage, but vervets prefer a diverse diet and do not
concentrate excessively on such.
On small holdings control measures may have to be taken to curb vervet activities.
The following can be done to minimize damage:
•
•
Make sure lands are clean of all waste.
Discard waste or unsaleable crop at the edge of a property where the vervet
monkeys enter.
If there are claims that damage caused by vervets is great, it would be worthwhile
investing in someone to patrol the area, or to install an electrified fence. Electric
fencing is quickly becoming an inexpensive and permanent trouble free solution if
erected properly.
Vervet monkeys do not eat the skins of commercial crops and one will always find
bite size pieces of skins, husks, shells and pips under their feeding sites. This
should aid in finding the true culprits before putting the blame on the more visible
and active vervets.
Other animals that exacerbate the problem and cause damage in areas where
vervets occur include:
•
•
Fruit bats.
•
Some antelope species.
•
Bush babies.
Porcupine.
188
•
•
Rabbits and hares.
Birds.
Many of the aforementioned animals come out only at night and are thus very
seldom seen causing damage.
Vervets are usually seen after the damage has occurred as they are diurnal, and
being inquisitive and opportunistic will investigate any food they find, even if it is
the left overs from a previous nights foraging by another animal. Before putting the
blame on vervets, it is essential that one determines that damage caused is
actually their doing.
Also, it is worth taking the advantages of having vervets
around into consideration - they control several pest insect species numbers, they
pollinate certain plant species, they assist in feeding other animals through their
methods of feeding, they ‘prune’ dead wood and old growth and they are
propagation mechanisms for some plants through the distribution of seeds by
means of their droppings and feeding methods.
Problems in areas where vervets and man live in close proximity to one another
are aggravated by people feeding the monkeys. This is very difficult to control and
once a vervet has learnt to get free food, it is hard to teach them differently. Being
quick learners they are fast to pick up where humans are getting the food from,
leading to the raiding of tents, bungalows and caravans in order to obtain a quick
meal when no one is around. When this stage has been reached the only solution
is electrification of perimeter fencing – this does however come at a cost (both
initial and ongoing in the form of maintenance). Other alternatives could be the
setting up of feeding areas away from human recreational and dwelling areas.
This does not appear to be a viable solution as the vervets become reliant on
humans for their food and lose their ability to forage successfully over the long
term. Sign boards stressing that people must not feed the monkeys should be
displayed.
189
Boards should state that all windows and doors must be closed before leaving and
that food should not be left out or put into easily accessible places like open or
non-monkey proofed dustbins. If people adhere to this, over time the monkeys will
look elsewhere for food and will not be seen as pests.
The basis of a successful vervet management strategy would thus incorporate the
aforementioned. An educational initiative with good public relations would further
assist in informing guests to wildlife areas as to how their actions affect the vervets.
Education would help people become aware of and appreciate the value of vervets
in their natural surroundings and the part they play in the ecosystems they form a
part of. Guests could be made aware of any threats to the well being of vervets
and could be involved in the management process, empowering them through
participation to become custodians of not just the vervets but the entire area and all
its inhabitants, to the benefit of all. A public relations initiative geared towards
informing farmers and land owners that have vervets living on their properties as to
the benefits of vervets, would go a long way towards creating an understanding
and a more tolerable attitude towards vervets in general.
In protected areas
management plans should be in place for the overall protection of habitats,
ecological processes, and living resources.
Such plans should be ‘living’
documents that are constantly changing and being updated or improved upon to
keep up with ever changing objectives and attitudes.
Where such management
plans are not in place it is crucial to determine the objectives of the area and to
setup management plans for the successful long term prosperity of such an area.
190
REFERENCES
ACOCKS, J.P.H. 1988. Veld types of South Africa.
3rd ed. Mem. Bot. Surv. S.
Afr. 40, Government Printer, Pretoria.
ADEYEMO, A.I.
1997.
Diurnal activities of green monkeys Cercopithecus
aethiops in Old Oyo National Park, Nigeria. S. Afr. J. Wildl. Res, 27(1): 2426.
AJAYI, S.S., AFOLAYAN, T. & MILLIGAN, K.
1981.
A survey of wildlife in
Kwiambana Game Reserve, Nigeria. Afr. Jnl. Ecol, 19: 295-298.
ALCOCK, J.
1993.
Animal Behaviour.
5th ed.
Massachusetts: Sinauer
Associates, Inc.
ALLAIN, C. & CLOITRE, M. 1991. Characterizing the lacunarity of random and
deterministic fractal sets. Physical Review, 44: 3553-3558.
ALTMANN, J.
1974.
Observational study of behaviour: sampling methods.
Behaviour, 49: 227-267.
ARNOLD, T.H. & DE WET, B.C. 1993. Plants of Southern Africa: Names and
distribution. Memoirs of the botanical Survey of South Africa, 62: 1-825.
BALDELLOU, M. & ADAN, A.
1997.
Time, gender and seasonality in vervet
activity: a chronobiological approach. Primates, 38: 31-43.
BALDELLOU, M. & ADAN, A. 1998. Diurnal and seasonal variations in vervet
monkeys’ activity. Psychological Reports, 83(2): 675-85.
191
BARBOUR, M.G., BURK, J.H. & PITTS, W.D. 1987. Terrestrial Plant Ecology. 2nd
ed. Massachusetts: The Benjamin/Cummings Publishing Company, Inc.
BARRETT, A.S.
2005.
Foraging ecology of the Vervet Monkey (Chlorocebus
aethiops) in Mixed Lowveld Bushveld and Sour Lowveld Bushveld of the
Blydeberg
Conservancy,
Northern
Province,
South
Africa.
Mtech.
dissertation. University of South Africa, Pretoria.
BARRETT, LOUISE. 2003. Personal Communication.
Doctor in Primatology.
University of Liverpool.
BARTLETT, M.S.
1978.
An introduction to the analysis of spatial patterns.
Supplement Advanced Applied Probability, 10: 1-13.
BARTON, R.A., WHITEN, A., STRUM, S.C., BYRNE, R.W. & SIMPSON, A.J.
1992. Habitat use and resource availability in baboons. Animal Behaviour,
43: 831-844.
BASCKIN, D.R. & KRIGE, P.D.
1973. Some preliminary observations on the
behaviour of an urban troop of vervet monkeys (Cercopithecus aethiops)
during the birth season. J. Behav. Sci, 1: 287-296.
BERCOVITCH, F.B. 1983. Time budgets and consortships in olive baboons Papio
anubis. Folia Primatology, 41: 180-190.
BEZUIDENHOUT, H. 1993. Syntaxonomy and synecology of Western Transvaal
Grasslands. Ph.D. dissertation, University of Pretoria, Pretoria.
192
BEZUIDENHOUT, H. 1996. The major vegetation communities of the Augrabies
Falls National Park, northern Cape. 1. The southern section. Koedoe, 39: 724.
BLOM, A., ALERS, M.P.T., FEISTNER, A.T.C., BARNES, R.F.W. & BARNES, K.L.
1992. Primates in Gabon - current status and distribution. Oryx, 26(4): 223234.
BOOTH, A.H. 1979. The Distribution of Primates in the Gold Coast. In: Sussman,
R.W.
(Ed.).
Primate Ecology.
Problem-oriented field studies.
Wiley,
Chichester & New York: chap. 7: 139-154.
BRAUN-BLANQUET, J. 1932. Plant sociology: the study of plant communities.
New York: McGraw-Hill.
BREDENKAMP, G.J., JOUBERT A.F. & BEZUIDENHOUT, H.
1989.
A
reconnaissance survey of the vegetation of the plains in the PotchefstroomFochville-Parys Area. South African Journal of Botany, 55: 199-206.
BREDENKAMP, G.J. & BEZUIDENHOUT, H. 1995. A proposed procedure for the
analysis of large data sets in the classification of South African Grasslands.
Koedoe, 38(1): 33-39.
BREDENCAMP, G. & VAN ROOYEN, N. 1998a. Mixed Lowveld Bushveld. In:
Low, A.B. & Rebelo, A.G. (eds) Vegetation of South Africa, Lesotho and
Swaziland. 2nd ed. Dept Environmental Affairs and Tourism, Pretoria.
BREDENCAMP, G. & VAN ROOYEN, N. 1998b. Sour Lowveld Bushveld. In:
Low, A.B. & Rebelo, A.G. (eds) Vegetation of South Africa, Lesotho and
Swaziland. 2nd ed. Dept Environmental Affairs and Tourism, Pretoria.
193
BRENNAN, E.J., ELSE, J.G. & ALTMANN, J. 1985. Ecology and behaviour of a
pest primate: vervet monkeys in a tourist-lodge habitat. Afr. J. Ecol, 23: 3544.
BRONIKOWSKI, A.M. & ALTMANN, J. 1996. Foraging in a variable environment:
weather patterns and the behavioural ecology of baboons. Behav. Ecol.
Sociobiol, 39: 11-25.
BROWN, J.L. 1982. Optimal group size in territorial animals. J. theor. Biol., 95:
793-810.
BROWN, L.R.
1997.
A plant ecological and wildlife management plan of the
Borakalalo Nature Reserve, North-west Province.
Ph.D.
dissertation.
University of Pretoria, Pretoria.
BROWN, L.R. & BREDENKAMP, G.J. 1994. The phytosociology of the southern
section of the Borakalalo Nature Reserve, South Africa. Koedoe, 37: 59-72.
BROWN, L.R., BREDENKAMP, G.J. & VAN ROOYEN, N.
1996.
The
phytosociology of the northern section of the Borakalalo Nature Reserve.
Koedoe, 39(1): 9-24.
BRUORTON, M. R., DAVIS, C. L. & PERRIN, M.R. 1991. Gut microflora of vervet
and samango monkeys in relation to diet.
Applied and Environmental
Microbiology, 57: 573-578.
BRUTON, M.N.
1978.
Recent mammal records from eastern Tongaland in
Kwazulu, with notes on Hippopotamus in lake Sibaka. Lammergeyer, 24: 1927.
194
BUCKLE, C.
1992.
Landforms in Africa: An Introduction to Geomorphology.
Essex: Longman Group Ltd.
CAUGHLEY, G. & SINCLAIR, A.R.E. 1994. Wildlife Ecology and Management.
Canada: Oxford University Press.
CHAPMAN, C. 1985. The influence of habitat on behaviour in a group of St. Kitts
green monkeys. Journal of Zoology, 206: 311-320.
CHAPMAN, C.A. 1988. Patch depletion by the spider and howling monkeys of
Santa Rosa National Park, Costa Rica. Behaviour, 105: 99-116.
CHENEY, D.L. 1987. Interactions and relationships between groups. In: Primate
Societies (Eds B.B. Smuts, D.L. Cheney, R.M. Seyfarth, R.W. Wrangham and
T.T. Strushaker). University of Chicago Press, Chicago.
CHENEY, D.L., LEE, P.C. & SEYFARTH, R.M. 1981. Behavioural correlates of
non-random mortality among free-ranging female vervet monkeys. Behav.
Ecol. Sociobiol, 9: 153-161.
CHENEY, D.L. & SEYFARTH, R.M. 1983. Nonrandom dispersal in free-ranging
vervet monkeys: social and genetic consequences. Am. Nat, 122(3): 392412.
CHENEY, D.L. & SEYFARTH, R.M. 1986. The recognition of social alliances by
vervet monkeys. Anim. Behav, 34: 1722-1731.
CHENEY, D.L., & SEYFARTH, R.M.
1987.
The influence of intergroup
competition on the survival and reproduction of female vervet monkeys.
Behav. Ecol. Sociobiol, 21: 375-386.
195
CHENEY, D.L., SEYFARTH, R.M., ANDELMAN, S.J. & LEE, P.C.
1988.
Reproductive success in vervet monkeys. In Reproductive success, ed. T.H.
Clutton-Brock. Chicago: University of Chicago Press.
CHENEY, D.L. & SEYFARTH, R.M. 1992. How Monkeys See the World – Inside
the Mind of Another Species. Chicago: University of Chicago Press.
CILLIERS, S.S.
1998.
Potchefstroom,
Phytosociological studies of urban open spaces in
North
West
Province,
South
Africa.
Ph.D.
thesis,
Potchefstroom University for CHE, Potchefstroom.
CLUTTON-BROCK, T.H.
1975.
Ranging behaviour of red colobus (Colobus
badius tephrosceles), in the Gombe National Park. Animal Behaviour, 23:
706-722.
CLUTTON-BROCK, T.H. 1977. Some aspects of intraspecific variation in feeding
and ranging behaviour in primates. In Primate ecology: Studies of feeding
and ranging behaviour in lemurs, monkeys and apes, ed. T.H. Clutton-Brock.
London: Academic Press.
CLUTTON-BROCK, T.H. & HARVEY, P.H. 1977. Primate ecology and social
organization. Journal of Zoology, 183: 1-39.
COLLINS ENGLISH DICTIONARY & THESAURUS. 1992. vs 1.5. Harper Collins.
COLLINSON, R.F.H. 1985. Selecting Wildlife Census Techniques. Monograph 6.
University of Natal: Institute of Natural Resources.
COWLING, R.M., RICHARDSON, D.M. & PIERCE, S.M. (ed.). 1997. Vegetation
of Southern Africa. Cambridge: Cambridge University Press.
196
CROOK, J.H. & GARTLAN, J.S. 1966. Evolution of primate societies. Nature,
210: 1200-1203.
DAVIS, J.C. 1986. Statistics and data analysis in Geology. 2nd ed. New York:
John Wiley & Sons, Inc.
DAWSON, G.S. 1979. The use of time and space by the Panamanian tamarin
Saguinus Oedipus. Folia primatol, 31: 253-283.
DE GRAAFF, G. & RAUTENBACH, I.L. 1983. A survey of mammals in the newly
proclaimed Karoo National Park, South Africa. Ann Mus Roy Afr Cent, 237:
89-99.
DE MOOR, P.P. & STEFFENS, F.E. 1972. The movements of vervet monkeys
(Cercopithecus aethiops) within their ranges as revealed by radio tracking.
Journal of Animal Ecology, 41(3): 677-687.
DEALL, G.B. 1985. A plant-ecological study of the Eastern Transvaal escarpment
in the Sabie area. M.sc. Thesis, University of Pretoria, Pretoria.
DEALL, G.B., THERON, G.K., WESTVAAL, R.H. 1989. The vegetation ecology of
the Eastern Transvaal Escarpment in the Sabie area.
2.
Floristic
classification. Bothalia, 19: 69-89.
DEFLER, T.R.
1995.
The time budget of a Group of Wild Woolly Monkeys
(Lagothrix lagotricha). International Journal of Primatology, 16: 107–120.
DONALDSON, C.H. 1978. Evaluation of Cenchrus ciliaris: II. A comparison of
bushveld, de-bushed veld and bushveld combined with Cenchrus pastures.
Proc. Grassld Soc. Sth. Afr, 2:137-141.
197
DUNBAR, R. & BARRETT, L. 2000. Cousins Our Primate Relatives. London:
BBC Worldwide Ltd.
DUNBAR, R.I.M. & DUNBAR, E.P.
1974.
Ecological relations and niche
separation between sympatric terrestrial primates in Ethiopia. Folia Primatol,
21: 36-60.
DUNHAM, K.M. 1994. The effect of drought on the larger mammal populations of
Zambezi riverine woodlands. Jnl. Zool, 234(3): 489-526.
DYE, P.J. & SPEAR, P.T.
1982.
The effects of bush clearing and rainfall
variability on grass yield and composition in south-west Zimbabwe.
Zimbabwe Journal of Agricultural Resources, 20: 103-118.
ECKHARDT, H.C. 1993. A synecological study of the vegetation of the northeastern Orange Free State. M.Sc. thesis. University of Pretoria, Pretoria.
EISENBERG, J.F., MUCKENHIRN, N. & RUDRAN, R.
1972.
The relations
between ecology and social structure in primates. Science, 176: 863-874.
ELSE, J.G.
1991.
Non-human primates as pests.
In Primate Responses to
Environmental Change, ed. H.O. Box. London: Chapman and Hall.
ESTES, R.D.
1992.
Behaviour Guide to African Mammals.
Los Angeles:
University of California Press.
FEDIGAN, L. & FEDIGAN, L.M. 1988. Cercopithecus aethiops: a review of field
studies. In: Gautier-Hion A., Bourlière F., Gautier J., Kingdon J. (Eds). A
Primate Radiation: Evolutionary Biology of the African Guenons. Cambridge
University Press, New York: pp 389-411.
198
FIMBEL, C. 1994. The relative use of abandoned farm clearings and old forest
habitats by primates and a forest antelope at Tiwai, Sierra Leone, West
Africa. Biological Conservation, 70: 277-286.
FULS, E.R. 1993. Vegetation ecology of the northern Orange Free State. Ph.D.
dissertation. University of Pretoria, Pretoria.
FULS, E.R., BREDENKAMP, G.J. & VAN ROOYEN, N.
1992.
The plant
communities of the undulating grassland of Vredefort – Kroonstad – Lindley –
Heilbron area, northern Orange Free State. South African Journal of Botany,
58: 224-230.
GEERLING, G. & BOKDM, J. 1973. Fauna of the Comoé National Park, Ivory
Coast. Biological Conservation, 5(4): 251-257.
GRIFFIN, D.R. 1984. Animal thinking. Cambridge, Mass.: Harvard University
Press.
HAGAN, J.E., EASTMAN, J.R. & AUBLE, J. 1998. Cartalinx the spatial data
builder – Users guide. Clark University, Worcester, USA.
HANYA, G.
2004.
Seasonal Variations in the Activity Budget of Japanese
Macaques in the Coniferous Forest of Yakushima: Effects of Food and
Temperature. American Journal of Primatology, 63: 165–177.
HARRISON, M.J.S.
1983.
Territorial behaviour in the green monkey,
Cercopithecus sabaeus: seasonal defence of local supplies. Behav. Ecol.
Sociobiol, 12: 85-94.
199
HARRISON, M.J.S.
1983a. Age and sex differences in the diet and feeding
strategies of the green monkeys, Cercopithecus sabaeus. Animal Behaviour,
31: 969-977.
HARRISON, M.J.S.
1983b. Patterns of range use by the green monkey,
Cercopithecus sabaeus, at Mt. Assirik, Senegal. Folia Primatol, 41: 157-179.
HARRISON, M.J.S. 1984. Optimal foraging strategies in the diet of the green
monkeys, Cercopithecus sabaeus, at Mt. Assirik, Senegal. Int. J. Primatol, 5:
435-471.
HARRISON, M.J.S.
1985.
Time budget of the green monkey, Cercopithecus
sabaeus: some optimal strategies. International Journal of Primatology, 6:
351–376.
HAUSER, M.D. & FAIRBANKS, L.A.
1988.
Mother-offspring conflict in vervet
monkeys: variation in response to ecological conditions. Animal Behaviour,
36: 802-813.
HENNEKENS, S.M. 1996. Megatab: a visual editor for phytosociological tables.
Ulft: Giesen.
HENNEKINS, S. 1998. TURBOVEG: Clipper database management software for
storage, selection, and export of vegetation data (relevés). Netherlands.
HENZI, S.P. 1982. Some aspects of visual signaling and social organization in the
vervet monkey (Cercopithecus aethiops pygerthrus).
University of Natal.
200
Ph.D. dissertation.
HENZI, S.P.
2003.
Personal Communication.
Professor in Psychology.
University of Central Lancashire.
HILL, M.O. 1979. TWINSPAN: A Fortran program for arranging multivariate data
in an ordered two-way table by classification of individuals and attributes.
New York: Cornell University.
HILL, R.A., BARRETT, L., GAYNOR, D., WEINGRILL, T., DIXON, P., PAYNE, H.
& HENZI, S.P. 2003. Day length, latitude and behavioural (in)flexibility in
baboons (Papio cynocephalus ursinus). Behav. Ecol. Sociobiol, 53: 278-286.
HILL, R.A., WEINGRILL, T., BARRETT, L. & HENZI, S.P.
2004.
Indices of
environmental temperatures for primates in open habitats. Primates, 45: 7–
13.
ISBELL, L.A., PRUETZ, J.D. & YOUNG, T.P.
1998.
Movements of vervets
(Cercopithecus aethiops) and patas monkeys (Erythrocebus patas) as
estimators of food resource size, density and distribution.
Behav.
Ecol.
Sociobiol, 42: 123-133.
KAMIL, A.C., KREBS, J.R. & PULLIAM, H.R. 1987. Foraging behaviour. New
York: Plenum Press.
KAMIL, A.C. & ROITBLAT, H.L.
1985.
The ecology of foraging behaviour:
Implications for animal learning and memory. Ann. Rev. Psych, 36: 141-169.
KAVANAGH, M. 1978. The diet and feeding behaviour of Cercopithecus aethiops
tantalus. Folia Primatol, 30: 30-63.
201
KAVANAGH, M. 1980. Invasion of the forest by an African savannah monkey:
behavioural adaptations. Behaviour, 73: 238-259.
KENT, M. & COKER, P. 1997. Vegetation Description and Ananlysis – A Practical
Approach. New York: John Wiley & Sons.
KINGDON, J. 1997. The Kingdon field guide to African Mammals. Academic
Press, New York: Natural World.
KOOIJ, M.S., BREDENKAMP, G.J. & THERON, G.K. 1990. Classification of the
vegetation of the B land type in the north-western Orange Free State. South
African Journal of Botany, 56: 309-318.
KREBS, C. J. 1989. Ecological methodology. New York: Harper and Row.
KREBS, J.R. & DAVIES, N.B. 1999. An Introduction to Behavioural Ecology. 3rd
ed. London: Blackwell Science Ltd.
KREBS, J.R. & MCCLEERY, R.H. 1984. Optimization in behavioural ecology. In
Behavioural ecology: An evolutionary approach, ed. J.R. Krebs and N.B.
Davies. Oxford: Blackwell Scientific.
LAND TYPE SURVEY STAFF. 1989. Land types of the maps 2330 Tzaneen,
2430 Pilgrims Rest. Memoirs on the Agricultural Natural Resources of South
Africa, 12.
LAWES M.J., HENZI, S.P. & PERRIN, M.R. 1990. Diet and feeding behaviour of
samango monkeys (Cercopithecus mitis labiatus) in Ngoye.
Primatologica, 54: 57-69.
202
Folia
LAWES, M.J. & PIPER, S.E. 1992. Activity patterns in free-ranging samango
monkeys (Cercopithecus mitis erythrarchus Peters, 1852) at the southern
range limit. Folia Primatology, 59: 186-202.
LEE, P.C.
1984.
Ecological constraints on the social development of vervet
monkeys. Behaviour, 91: 245-262.
LEE, P.C. 1987. Nutrition, fertility and maternal investment in primates. Journal of
Zoology, 213: 409-422.
LEE, P.C., BRENAN, J.P., ELSE, J.G. & ALTMAN, J.
1986.
Ecology and
behaviour of vervet monkeys in a tourist lodge habitat. In: Else J.G., Lee P.C.
(Eds). Primate ecology and conservation. Selected Proceedings of the 10th
Congress Int. Primatological Society, Nairobi, Kenya (July 1984). Cambridge
University Press, Cambridge, U.K: chap. V.3, 229-236.
LEE, P.C. & HAUSER, M.D. 1995. Diet, food selection, long term habitat changes
and local extinction in vervet monkeys. Am. J. Primatol, 20: 131-132.
LEE, P.C. & HAUSER, M.D.
1998.
Long-term consequences of changes in
territory quality on feeding and reproductive strategies of vervet monkeys.
Journal of Animal Ecology, 67: 347-358.
LERNOULD, J. 1988. Classification and geographical distribution of guenons: a
review. In: Gautier-Hion A., Bourlière F., Gautier J., Kingdon J. (Eds). A
Primate Radiation: Evolutionary Biology of the African Guenons. Cambridge
University Press, New York.
LYNCH, C.D. 1983. The mammals of the Orange Free State. Mem. van die
Nasionale Mus, 18: 1-218.
203
LYNCH, C.D. 1989. The mammals of the north-east Cape Province. Mem. van
die Nasionale Mus, 25: 1-116.
MACLEAN, G.L. 1990. Ornithology for Africa. Pietermaritzburg: University of
Natal Press.
MAPLES, W.R., MAPLES, M.K., GREENHOOD, W.F. & WALEK, M.L.
1976.
Adaptations of crop raiding baboons in Kenya. Am. J. Phys. Anthrop, 45:
309-316.
MARAIS, A.J.
2004.
Resource utilisation of the chacma baboon in different
vegetation types in north-eastern mountain sour veld, Blyde Canyon Nature
Reserve. Mtech. dissertation. University of South Africa, Pretoria.
MATTHEE, J.F. & VAN SCHALKWYK, C.J. 1984. A Primer on Soil Conservation.
Bulletin No. 399., Dept of Agriculture. Government Printer, Pretoria.
MATTHEWS, W.S. 1991. Phytosociology of the North-eastern Mountain sourveld.
Msc. Thesis, University of Pretoria, Pretoria.
MATTHEWS, W.S., BREDENKAMP, G.J. & VAN ROOYEN, N.
1994. The
phytosociology and syntaxonomy of relative low-altitude areas in the Northeastern Mountain Sourveld, in the eastern Transvaal escarpment region.
Koedoe, 37(2).
MICHAEL, J.S. 1983. Age and sex differences in the diet and feeding strategies
of the green monkeys. Anim. Beha, 31: 961-977.
MILLS, G. & HES, L. 1997. The complete book of Southern African mammals.
Struik Publishers.
204
MILTON, K.
1980.
The foraging strategy of Howler Monkeys.
New York,
Columbia University Press.
MITANI, J.C. & RODMAN, P.S. 1979. Territoriality: the relation of ranging pattern
and home range size to defendability, with an analysis of territoriality among
primate species. Behavioural Ecology and Sociobiology, 5: 241-251.
MOORE, A., VAN NIEKERK, J.P., KNIGHT, I.W. & WESSELS, H. 1985. The
effect of Tebuthiuron on the vegetation of the thorn bushveld of the northern
Cape: a preliminary report. J. Grassld Soc. Sth. Afr, 2: 7-10.
MORENO-BLACK, G.S. & MAPLES, W.R. 1977. Differential habitat utilisation of
four Cercopithecidae in a Kenyan forest. Folia Primatol, 27: 85-107.
MUELLER-DOMBOIS, D. & ELLENBERG, H.
1974.
Aims and methods of
vegetation ecology. New York: Wiley & Sons.
NAGEL, U. 1973. A comparison of anubis baboons, hamadryas baboons and
their hybrids at a species border in Ethiopia. Folia Primatol, 19: 104-166.
NAKAGAWA, N.
1989.
Feeding strategies of Japanese monkeys against
deterioration of habitat quality. Primates, 30: 1-16.
NAKAGAWA, N.
1999.
Differential habitat utilisation by Patas monkeys
(Erythrocebus patas) and Tantalus monkeys (Cercopithecus aethiops
tantalus) living sympatrically in northern Cameroon.
Primatology, 49: 243-264.
205
American Journal of
NAKAGAWA, N.
2000.
Foraging Energetics in Patas Monkeys (Erythrocebus
patas) and Tantalus Monkeys (Cercopithecus aethiops tantalus): Implications
for Reproductive Seasonality. American Journal of Primatology, 52: 169–185.
NAKAGAWA, N.
2003.
Difference in food selection between patas monkeys
(Erythrocebus patas) and tantalus monkeys (Cercopithecus aethiops tantalus)
in Kala Maloue National Park, Cameroon, in relation to nutrient content.
Primates, 44: 3-11.
NIEVERGELT, B. 1981. Ibexes in an African Environment. Ecology and social
system of the Walia Ibex in the Simen Mountains, Ethiopia. Springer Verlag:
Berlin and New York Ecology Studies.
OATES, J.F. 1987. Food distribution and foraging behaviour. Pp. 197–209 in
PRIMATE SOCIETIES.
B.B. Smuts; D.L. Cheney; R.M. Seyfarth; T.
Struhsaker; R.W. Wrangham, eds. Chicago, University of Chicago Press.
OATES, J.F. 1996. African Primates Status Survey and Conservation Action plan.
IUCN/SSC Primate Specialist Group. S.I.
OVERDORFF, D.J. 1996. Ecological correlates to activity and habitat use of two
prosimian primates: Eulemur rubriventer and Eulemur fulvus rufus in
Madagascar. American Journal of Primatology, 40: 327-342.
PASSAMANI, M.
1998.
Activity Budget of Geoffroy’s Marmoset (Callithrix
geoffroyi) in an Atlantic Forest in Southeastern Brazil. American Journal of
Primatology, 46: 333-340.
206
PERES, C.A. 1993. Diet and feeding ecology of saddleback (Saguinus fuscicollis)
and moustached (S. mystax) tamarins in an Amazonian terra firma forest.
Journal of Zoology, 230: 567–592.
POULSEN, J.R., CLARK, C.J. & SMITH, T.B. 2001. Seasonal variation in the
feeding ecology of the Grey-Cheeked Mangabey (Lophocebus albigena) in
Cameroon. American Journal of Primatology, 54: 91-105.
PRINGLE, J.A. 1974. The distribution of mammals in Natal. Part I. Primates,
Hyracoidea, Lagomorpha (except Lepus), Pholidota and Tubulidentata. Ann.
Natal Mus, 22(1): 173-186.
PRUETZ, J.D. & ISBELL, L.A. 1999. What makes a food contestable? Food
properties and contest competition in vervets and patas monkeys in Laikipia,
Kenya. American Journal of Physical Anthropology, 28: 225-226.
PRUETZ, J.L. & ISBELL, L.A. 2000. Correlations of food distribution and patch
size with agonistic interactions in female vervets (Chlorocebus aethiops) and
patas monkeys (Erythrocebus patas) living in simple habitats. Behav. Ecol.
Sociobiol, 49: 38-47.
RABOY, B.E. & DIETZ, J.M.
2004.
Diet, foraging, and use of space in wild
Golden-Headed Lion Tamarins. American Journal of Primatology, 63: 1–15.
REMIS, M.J. 1997. Western lowland gorillas (Gorilla gorilla gorilla) as seasonal
frugivores: use of variable resources. American Journal of Primatology, 43:
87–109.
207
RYLANDS, A.B. 1982. The behaviour and ecology of three species of marmosets
and tamarins (CALLITRICHIDAE, primates) in Brazil. PhD thesis, University
of Cambridge, Cambridge, UK.
SAJ, T., SICOTTE, P. & PATERSON, J.D.
1999.
Influence of human food
consumption on the time budget of vervets. Int. J. Primatology, 20: 977-994.
SCHOLTZ, C.H. & HOLM, E. (ed.). 1989. Insects of Southern Africa. Durban:
Butterworths.
SKAIFE, S.H., LEDGER, J. & BANNISTER, A. 1979. African Insect Life. 2nd ed.
Cape Town: Struik Publishers.
SKINNER, J.D. & SMITHERS, R.H.N.
1990.
The Mammals of the Southern
African Subregion. 2nd ed. South Africa: University of Pretoria.
SMIT, G.N., RICHTER, C.G.F. & AUCAMP, A.J. 1999. Bush encroachment: An
approach to understanding and managing the problem. In: Veld Management
in South Africa, ed. N. Tainton. University of Natal Press.
SMITH, C.C. 1977. Feeding behaviour and social organisation in howler monkey.
Pp. 97–126 in PRIMATE ECOLOGY.
T.H. Clutton-Brock ed.
London,
Academic Press.
SOIL CLASSIFICATION WORKING GROUP.
taxonomic system for South Africa.
1991.
Soil classification a
Memoirs on the Agricultural Natural
Resources of South Africa, 15: 1-257.
SOUTH AFRICA (REPUBLIC). 1986. 1:250 000 Geological Series 2430 Pilgrims
Rest. Government Printer, Pretoria.
208
STRIER, K.B. 1999. Primate behavioural ecology. Needham Heights, MA: Allyn
& Bacon.
STRUHSAKER, T.T.
1967.
Auditory Communication Among Vervet Monkeys
(Chlorocebus aethiops). In: Social Communication among Primates, ed. S.A.
Altmann. University of Chicago Press.
STRUHSAKER, T.T.
1967a.
Social structure among vervet monkeys
(Cercopithecus aethiops). Behaviour, 29: 83-121.
STRUHSAKER, T.T. 1967b. Behaviour of Vervet Monkeys (CERCOPITHECUS
AETHIOPS). Zoology, 82: 1-64.
STRUHSAKER, T.T.
1967c.
Ecology of Vervet Monkeys (Cercopithecus
aethiops). Ecology, 48: 891-904.
STRUHSAKER, T.T. 1979. Correlates of ecology and social organisation among
African cercopithecines. In: Primate Ecology, ed. R.W. Sussman. Problemoriented field studies. Wiley, Chichester & New York: chap. 20: 391-404.
STUART, C. & STUART, T. 1997. Field guide to the larger mammals of Africa.
Struik Publishers, Cape Town.
SWART, J. & LAWES, M.J. 1996. The effect of habitat patch connectivity on
samango
monkey
(Cercopithecus
mitis)
metapopulation
persistence.
Ecological Modelling, 93: 57-74.
TEMBO, A. 1994. Population characteristics of the vervet monkey in the Mosi-OaTunya National Park, Zambia. Afr. Jnl. Ecol, 32: 72-74.
209
TEMBO, A. 1995. A survey of large mammals in Sioma-Ngwezi Park, Zambia.
Afr. Jnl. Ecol, 33: 173-174.
TERBORGH, J. 1986. Community aspects of frugivory in tropical forests. In:
Estrada A., Flemming T.H., editors.
Frugivores and seed dispersal.
Dordrecht: D.W. Junk Publishers. p 371-384.
TUELLER, P.T. 1988. Vegetation science applications for rangeland analysis and
management. Dordrecht: Kluwer Academic Publishers.
TUTIN, C.E.G., HAM, R.M., WHITE, L.J.T. & HARRISON, M.J.S.
1997.
The
primate community of the Lopé Reserve, Gabon: diets, responses to fruit
scarcity, and effects on biomass. American Journal of Primatology, 42: 1–24.
TYSON, P.D. & PRESTON-WHYTE, R.A. 2000. The Weather and Climate of
Southern Africa. Cape Town: Oxford University Press.
VAN DER SCHIJFF, H.P. 1963. A preliminary account of the vegetation of the
Mariepskop Complex. Transvaal Provincial Administration. Fauna and Flora,
14: 42-53.
VAN DER SCHIJFF, H.P. & SCHOONRAAD, E.
1971.
The flora of the
Mariepskop Complex. Bothalia, 10, 3: 461-500.
VAN OUDTSHOORN, F. 1999. Guide to grasses of southern Africa. Pretoria:
Briza Publications.
210
VAN ROOYEN, N., THERON, G.K. & GROBBELAAR, N.
1981.
A floristic
description and structural analysis of the plant communities of the Punda
Milia-Pafuri-Wambiya area in the Kruger National Park, Republic of South
Africa. 1. The hygrophilous communities. South African Journal of Botany
47: 213-246.
VAN ZYL, D.
2003.
South African Weather and Atmospheric Phenomena.
Pretoria: Briza Publications.
VEDDER, A.L. 1984. Movement patterns of free-ranging mountain gorillas (Gorilla
gorilla beringei) and their relation to food availability. American Journal of
Primatology, 7: 73-88.
VILJOEN, P.J.
1982.
The distribution and population status of the larger
mammals in Kaokoland, South West Africa/Namibia. Cimbebasia, A7: 7-33.
VISSER, D.J.L. (ed.).
1989.
The Geology of the Republics of South Africa,
Transkei, Bophuthatswana, Venda and Ciskei and the Kingdoms of Lesotho
and Swaziland.
Geological Survey, Explanation of the 1: 1 000 000
th
Geological Map, 4 ed. Government Printer, Pretoria.
WALRAVEN, F.
1989.
The Geology of the Pilgrim’s Rest Area.
Geological
Survey, Explanation of Sheet 2430. Government Printer, Pretoria.
WERGER, M.J.A.
1974.
On concepts and techniques applied in the Zurich-
Montpellier method of vegetation survey. Bothalia, 11: 309-323.
WESTHOFF, V. & VAN DER MAAREL, E.
1978.
20. The Braun-Blanquet
approach. In: Classification of plant communities, ed. R.H. Whittaker, pp.
289-399. Junk, The Hague.
211
WHITTAKER, R.H.
1978.
Direct gradient analysis.
communities, ed. R.H. Whittaker, pp. 7-50.
In: Ordination of plant
Junk, Groningen, The
Netherlands.
WHITTEN, P.L.
1988. Effects of patch quality and feeding subgroup size on
feeding success in vervet monkeys (Cercopithecus aethiops).
Behaviour,
105: 35-52.
WILSON , D.E. & REEDER, D.M. (eds.). 1993. Mammal Species of the World: A
Taxonomic and Geographic Reference.
2nd ed.
Smithsonian Institution
Press, Washington D.C.
WRANGHAM, R.W. & WATERMAN, P.G. 1981. Feeding behaviour of vervet
monkeys on Acacia tortilis and Acacia xanthophloea with special reference to
reproductive strategies and condensed tannin production. J. Anim. Ecol, 50:
715-731.
YALDEN, D.W., LARGEN, M.J. & KOCK, D. 1977. Catalogue of the mammals of
Ethiopia 3. Primates. Monitore Zoologico Italiano, suppl, IX: 1-52.
YALDEN, D.W., LARGEN, M.J., Kock, D. & HILLMAN, J.C. 1996. Catalogue of
the mammals of Ethiopia and Eritrea. 7. Revised checklist, zoogeography
and conservation. Tropical Zoology, 9: 73-164.
ZINNER, D., TORKLER, F. & PELÁEZ, F.
2001.
Distribution and habitat of
hamadryas baboons (Papio h. hamadryas) in Eritrea. Int. J. Primatol., 22:
397-413.
212
ZINNER, D., PELÁEZ, F. & TORKLER, F. 2002. Distribution and habitat of grivet
monkeys (Cercopithecus aethiops aethiops) in eastern and central Eritrea.
Afr. J. Ecol., 40: 151-158.
213
APPENDIX 1
Plants prefixed with an asterisk are species recorded at the study site. Plants not
prefixed with an asterisk are found on the greater Blydeberg Conservancy and
could be present in the study area, but were not encountered and recorded during
the study.
ACANTHACEAE
Barleria elegans
B. gueinzii
B. maderaspatensis ssp. Rubiifolia
B. saxatilis
Blepharis maderaspatensis ssp. Maderaspatensis var.
maderaspatensis
Dyschoriste rogersii
Ecbolium revolutum
Hypoestes forskaolii
Hypoestes sp. Aff H. forskaolii
Isoglossa grantii
I. stipitata
Isoglossa sp.
Justicia flava
J. petiolaris spp. Petiolarus
J. protracta ssp. Rhodesiana
Monechma cleomoides
Phaulopsis longifolia
Ruellia cordata
R. otaviensis
R. patula
214
ANACARDIACEAE
* Lannea discolor
* Ozoroa paniculosa
* O. sphaerocarpa
* Rhus dentata
* R. lancea
* R. leptodictya
* R. tumulicola
* Sclerocarya birrea
APIACEAE
* Steganotaenia araliacea
APOCYNACEAE
* Acokanthera oppositifolia
* Carrissa bispinosa
* C. edulis
Diplorhynchus condylocarpon
* Rauvolfia caffra
* Strophanthus gerrardii
* S. speciousus
ARACEAE
Stylochiton natalense
ARALIACEAE
* Cussonia spicata
215
ASCLEPIADACEAE
Ceropegia ampliata
Cordylogyne globosa
Pachycarpus concolor
Pergularia daemia var. daemia
Sarcostemma viminale
Secamone parvifolia
ASTERACEAE
Arctotis venusta
* Bidens pilosa *
Conyza attenuata
Eclipta prostrata
Gerbera jamesonii
Laggera crispata
Mikania capensis
* Vernonia adoensis
V. neocorymbosa
* Tagetes minuta *
* Xanthium spinosum
BALANITACEAE
* Balanites maughamii
BALANOPHORACEAE
Sacrophyte sanguinea ssp. Sanguinea
BIGNONIACEAE
* Markhamia zanzibarica
* Rhigozum obovatum
216
* Tecoma capensis
BOMBACACEAE
* Adansonia digitata
BORAGINACEAE
Cordia ovalis
* Ehretia amoena
* E. rigida
Heliotropium steudneri
BURSERACEAE
* Commiphora africana
* C. harveyi
* C. glandulosa
* C. mollis
CACTACEAE
* Opuntia ficus-indica *
CAESALPINIACEAE
Bauhinia tomentosa
Chamaecrista absus
Chamaecrista plumosa var. erecta
* Peltophorum africanum
* Piliostigma thonningii
* Schotia brachypetala
Senna occidentalis *
217
CANELLACEAE
Warburgia salutaris
CAPPARACEAE
* Boscia albitrunca
Capparis fascicularis
* C. tormentosa
Cleome gynandra
C. monophylla
* Maerua angolensis
M. edulis
M. juncea ssp. crustata
M. parvifolia
CELASTRACEAE
Cassine aethiopica
Catha edulis
Hippocratea africana var. richardiana
* H. crenata
H. longipetiolata
Gymnosporia senegalensis
* G. glaucophylla
Putterlickia pyracantha
CHENOPODIACEAE
Chenopodium ambrosiodes
C. carinatum
CLUSIACEAE
* Garcinia livingstonei
218
COMBRETACEAE
* Combretum apiculatum ssp. apiculatum
C. collinum ssp. Suluense
* C. erythrophyllum
* C.hereroense
* C. imberbe
* C. molle
* C. zeyheri
* Terminalia phanerophlebia
* T. sericea
COMMELINACEAE
Commelina erecta
CONVOLVULACEAE
Ipomoea albivenia
I. magnusiana
I. simplex
Merremia tridentata ssp. Angustifolia var. angustifolia
CRASSULACEAE
Crassula setulosa var. jenkinsii
CUCURBITACEAE
Corallocarpus bainessii
Trochomeria macrocarpa ssp. macrocarpa
DRACAENACEAE
* Sansevieria hyacinthoides
219
EBENACEAE
* Diospyros mespiliformes
D. villosa var. parvifolia
* Euclea crispa ssp. Crispa
* E. divinorum
E. natalensis ssp. angustifolia
* E. undulata
EQISETACEA
Equisetum ramosissimum
EUPHORBIACEAE
Acalypha petiolarus
A. villicaulis
* Bridelia mollis
Chamaesyce neopolycnemoides
Dalenchampia galpinii
* Flueggea virosa
Margaritaria discoidea ssp. Dicoidea
Phyllanthus burchellii
P. incurvus
P. reticulatus
* Pseudolachnostylis maprouneifolia
Securinega virosa
* Spirostachys africana
Tragia glabrata var. glabrata
T. durbanensis
220
FABACEAE
Abrus precatorius
* Argyrolobium velutinum
* Bolusanthus speciosus
Calpurnea aurea ssp. aurea
C. distans
C. doidgeae
C. monteiroi var. galpinii
Crotolaria capensis
* Dalbergia armata
* D. melanoxylon
Eriosema psoralioides
* Erythrina lysistemon
* Indigofera arrecta
I. hedyantha
I. swaziensis var. swaziensis
Lotononis carinata
* Mundulea sericea
Pearsonia cajanifolia ssp. cajanifolia
* Philenoptera violacea
Rhynchosia hirta
Sesbania sesban ssp. Sesban var. sesban
Strylosanthes fruiticosa
Tephrosia aequilata
T. purpurea ssp. Leptostachya
T. rhodesiaca var. rhodesiaca
Vigna nervosa
221
FLACOURTIACEAE
* Dovyalis caffra
* D. zeyheri
* Scolopia zeyheri
GERANIACEAE
Monsonia angustifolia
M. glauca
Pelargonium multicaule
* Pelargonium sp.
HETEROPYXIDACEAE
* Heteropyxis natalensis
HYPOXIDACEAE
* Hypoxis hemerocallidea
IRIDACEAE
Gladiolus crassifolius
Lapeirousia erythrantha
LABIATAE / LAMIACEAE
Aeollanthus parvifolius
Becium filamentosum
Becium sp. Nov. aff. B. knyanum
Endostemon tereticaulis
Hemizygia elliotii
H. petrensis
Leonotis ocymifolia
Leucas neuflizeana
222
Ocimum canum
O. urticifolium
Orthosiphon suffrutescens
Plectranthus hadiensis
Pycnostachys hadiensis
Tinnea rhodesiana
LILIACEAE
* Aloe dyeri
* A. marlothii
* Asparagus cooperi
* A. setaceus
* A. virgatus
Dipcadi viride
Eriospermum abyssinicum
Urginea sp.
LOBELIACEAE
* Lobelia sp.
LOGANIACEAE
* Nuxia oppositifolia
* Strychnos cocculoides
LORANTHACEAE
Pedistylis galpinii
Plicosephalus kalachariensis
Tieghemia bolusii
223
MALVACEACE
* Gossypium herbaceum var. africanum
Hibiscus calyphyllus
H. meyeri ssp. transvaalensis
* Pavonia columella
Sida alba
* S. cordifolia
MELIACEAE
* Trichilia emetica
Turraea nilotica
MENISPERMACEAE
Cissampelos mucronata
Cocculus hirsutus
MIMOSACEAE
* Albizia forbesii
A. harveyi
* A. versicolor
* Acacia burkei
* A. caffra
* A. exuvialis
* A. galpinii
* A. karroo
* A. nigrescens
* A. nilotica ssp. Kraussiana
* A. schweinfurthii
* A. tortilis
* Dichrostachys cinerea
224
MORACEAE
* Ficus ingens
* F. stuhlmannii
* F. sur
* F. sycomorus
MYRICACEAE
* Morella pilulifera
* M. serrata
MYRTACEAE
Syzygium cordatum
NYCTAGINACEAE
Boerhavia diffusa var. hirsuta
Commicarpus africanus
OCHNACEAE
Ochna inermis
OLACACEAE
Ximenia americana
* X. caffra var. natalensis
OLEACEAE
Jasminum fluminense
* Olea europaea
OPHIOGLOSSACEAE
Ophioglossum vulgatum
225
PASSIFLORACEAE
Adenia digitata
PERIPLOCACEAE
Raphionacme procumbens
PLUMBAGINACEAE
* Plumbago zeylanica
POACEAE
* Anthephora pubescens
* Aristida congesta
* A. stipitata
* Brachiaria brizantha
* Chloris virgata
* Cymbopogon excavatus
* Digitaria eriantha
* Diheteropogon filifolius
* Elionurus muticus
* Eragrostis lehmanniana
* E. rigidior
* E. superba
* Eustachys paspaloides
* Heteropogon contortus
* Hyparrhenia hirta
* Imperata cylindrica
* Melinis repens
* Panicum maximum
* Pogonarthria squarrosa
Sporobolus festivus
226
POLYGALACEAE
Polygala asbestina
P. sp. Aff. P. erioptera
P. sphenoptera
POLYGONACEAE
Persicaria serrulata
PORTULACACEAE
Talinum caffrum
PTAEROXYLACEAE
* Ptaeroxylon obliquum
RHAMNACEAE
* Berchemia discolor
* B. zeyheri
* Helinis integrifolius
* Ziziphus mucronata
ROSACEAE
* Leucosidea sericea
RUBIACEAE
Agathisanthemum bojeri var. bojeri
Anthospermum streyi
Breonadia salicina
* Canthium ciliatum
Catunaregam spinosa ssp. Spinosa
* Gardenia volkensii
227
* Hypercanthus amoenus
Kohautia caespitosa ssp. Brachyloba
Oxyanthus speciosus
Pachystigma pygmaeum
Pavetta catophylla
P. schumanniana
Pentodon pentandrus var. pentandrus
* Plectroniella armata
Psydrax livida
Pyrostria hystrix
Ticalysia lanceolata
Vangueria cyanescens
V. infausta
RUTACEAE
* Toddaliopsis bremekampii
* Vepris reflexa
SALICACEAE
Salix mucronata ssp. woodii
S. woodii
SANTALACEAE
Osyridocarpus schimperianus
Thesium deceptum
Thesium sp.
SAPINDACEAE
Cardiospermum halicacabum
* Pappea capensis
228
SAPOTACEAE
* Englerophytum magalismontanum
* Mimusops zeyheri
Sideroxylon inerme
SCROPHULARIACEAE
Alectra orobanchioides
Aptosimum lineare
* Halleria lucida
Striga bilabiara
SOLANACEAE
* Solanum panduriforme
STERCULIACEAE
* Dombeya cymosa
* D. rotundifolia var. rotundifolia
Hermannia quartiniana
H. tomentosa
Melhania didyma
M. forbesii
M. prostata
* Sterculia rogersii
Waltheria indica
STRELITZIACEAE
* Strelitzia nicolai
THUNBERGIACEAE
Thunbergia amoena
229
THYMELAEACEAE
Gnidia capitata
G. robusta
TILIACEAE
Corchorus asplenifolius
* C. kirkii
C. tridens
* Grewia flava
* G. flavescens
* G. hexamita
* G. monticola
* G. occidentalis
TURNERACEAE
Tricliceras longipedunculatum
ULMACEAE
* Celtis africana
* Chaetachme aristata
UMBELLIFERAE / APIACEAE
Heteromorpha pubescens
Steganotaenia araliacea
URTICACEAE
* Obetia tenax
* Pouzolzia mixta
230
VAHLIACEAE
Vahlia capensis ssp. vulgaris
VERBENACEAE
Clerodendrum ternatum var. ternatum
Lantana rugosa
Lanata sp.
* Vitex ferruginea subsp. amboniensis
VIOLACEAE
Hybanthus enneaspermus
VISCACEAE
Viscum combreticola
VITACEAE
Cissus cornifolia
231