Potential natural vegetation of eastern Africa. Volume 2: Description

Paulo van Breugel

Citation for published version (APA): van Breugel, P., Kindt, R., Lillesø, J-P. B., Bingham, M., Demissew, S., Dudley, C., ... Graudal, L. O. V. (2011). Potential natural vegetation of Eastern Africa (Ethiopia, Kenya, Malawi, Rwanda, Tanzania, Uganda and Zambia): Volume 7: Projected distributions of potential natural vegetation types and two important agroforestry species (Prunus Africana and Warburgia Ugandensis) for six possible future climates. Forest & Landscape, University of Copenhagen. Forest & Landscape Working Papers, No. 69/2011

Nomenclature African Flowering Plants Database = Abstract Question: How well does the forest classification system of the 1:5,000,000 vegetation map of Africa developed by Frank White correspond with classification systems and more extensive information on species assemblages of higher resolution maps developed for Ethiopia, Kenya, Malawi, Rwanda, Tanzania, Uganda and Zambia? Methods: We reviewed various national and sub-national vegetation maps for their potential in increasing the resolution of the African map. Associated documentation was consulted to compile species assemblages, and to identify indicator species, for national forest vegetation types. Indicator species were identified for each regional forest type by selecting those species that, among all the species listed for the same phytochorion (regional centre of endemism), were listed only for that forest type. For each of the national forest types, we counted the number of indicator species of the anticipated regional type. Floristic relationships (expressed by four different ecological distance measures) among national forest types were investigated based on distance-based redundancy analysis, permuta-tional multivariate analysis of variance (PERMANOVA) using distance matrices and hierarchical clustering. Results: For most of the national forests, the analysis of indicator species and floristic relationships confirmed the regional classification system for the majority of national forest types, including the allocation to different phytochoria. Permutation tests confirmed allocation of national forest types to regional typologies, although the number of possible permutations limited inferences for the Zambezian and Lake Victoria phytochoria. Two forest types from Ethiopia and Kenya did not correspond to regional forest types.

A syntaxonomic survey of Kenyan montane forests was performed in a field study from 1992-1996. Most forests encountered belong to the Juniperetea procerae floral community (cedar forests), of which the Juniperion procerae Faureo salignae-Ilicetum mitis on the wet mountaintops and the Myrsino africanae-Juniperetum procerae in drier areas, were most commonly encountered. On Mt Marsabit the Coffeo arabicaeRinoreetum convallarioidis was found as a new association of the Cassipourion malosanae. The top of Mt Nyiru is covered with large stands of the Hagenietea abyssinicae and extensive bamboo forests (Sinarundinarietea alpinae). Mathews Range harbours the largest forest tracts remaining in the dry north of Kenya. On the lower slopes of this mountain, a new alliance, assessed as Crotonion megalocarpi is described. Camphor forests (Ocotetea usambarensis) cover altitudes from 1,600-2,400 min the southern Aberdare Range. In the submontane Imenti and Ngaia forests, and the Nyambeni Hills, between 1,200-1,600 m altitude, a variety of forest types related to the Guineo Congolian rainforest were encountered. These forests are assessed as Lovoion swynnertonii. In the montane zone of Nyambeni dense bamboo forests cover the wetter areas, whereas drier parts are covered by cedar forests. On the drier hill slopes of southern Kenya the Juniperion procerae is the prevalent forest type. On the often mist-covered and cloudy hilltops, associations of the Cassipourion malosanae are growing. The forests around Nairobi clearly belong to the Brachylaenion huillensis. Although some syntaxa had to be newly described, the forests of the study areas clearly fit into the classification system of Bussmann & Beck (1995).

university of copenhagen Potential Natural Vegetation of Eastern Africa (Ethiopia, Kenya, Malawi, Rwanda, Tanzania, Uganda and Zambia). Volume 9 Atlas and Tree Species Composition for Rwanda Kindt, R.; van Breugel, Paulo; Lillesø, Jens-Peter Barnekow; Minani, V.; Ruffo, C.K.; Gapusi, J,; Jamnadass, R.; Graudal, Lars Publication date: 2014 Document version Publisher's PDF, also known as Version of record Citation for published version (APA): Kindt, R., van Breugel, P., Lillesø, J-P. B., Minani, V., Ruffo, C. K., Gapusi, J., ... Graudal, L. (2014). Potential Natural Vegetation of Eastern Africa (Ethiopia, Kenya, Malawi, Rwanda, Tanzania, Uganda and Zambia). Volume 9: Atlas and Tree Species Composition for Rwanda. Department of Geosciences and Natural Resource Management, University of Copenhagen. IGN Report Download date: 09. okt.. 2020 d e pa r t m e n t o f g e o s c i e n c e s a n d n at u r a l r e s o u r c e m a n a g e m e n t university of copenhagen Potential Natural Vegetation of Eastern Africa (Ethiopia, Kenya, Malawi, Rwanda, Tanzania, Uganda and Zambia) Volume 9. Atlas and Tree Species Composition for Rwanda R. Kindt, P. van Breugel, J-P.B. Lillesø, V. Minani, C.K. Ruffo, J. Gapusi, R. Jamnadass and L. Graudal IGN Report May 2014 d e pa r t m e n t o f g e o s c i e n c e s a n d n at u r a l r e s o u r c e m a n a g e m e n t university of copenhagen Potential Natural Vegetation of Eastern Africa (Ethiopia, Kenya, Malawi, Rwanda, Tanzania, Uganda and Zambia) Volume 9. Atlas and Tree Species Composition for Rwanda R. Kindt, P. van Breugel, J-P.B. Lillesø, V. Minani, C.K. Ruffo, J. Gapusi, R. Jamnadass and L. Graudal Title Potential natural vegetation of eastern Africa (Ethiopia, Kenya, Malawi, Rwanda, Tanzania, Uganda and Zambia) Volume 9. Atlas and Tree Species Composition for Rwanda Authors Kindt, R.2, van Breugel, P.1, Lillesø, J-P.B.1, Minani, V.3, Ruffo, C.K.3, Gapusi, J.4, Jamnadass, R.2, and Graudal, L.1 Collaborating Partners Forest and Landscape 2 World Agroforestry Centre 3 National Herbarium of Rwanda, Institut de Recherche Scientifique et Technologique 4 Rwanda National Tree Seed Centre, Rwanda Agriculture Board 1 Publisher Department of Geosciences and Natural Resource Management University of Copenhagen Phone: +45-353 31500 http://ign.ku.dk/english/ ISBN ISBN 978-87-7903-619-2 (paper) ISBN 978-87-7903-617-8 (digital) Layout Melita Jørgensen Citation Kindt, R., van Breugel, P., Lillesø, J-P.B., Minani, V., Ruffo, C.K., Gapusi, J., Jamnadass, R. and Graudal, L. 2014: Potential natural vegetation of eastern Africa. Volume 9. Atlas and tree species composition for Rwanda. Department of Geosciences and Natural Resource Management, University of Copenhagen. Citation allowed with clear source indication All rights reserved. This work is subject to copyright under the provisions of the Danish Copyright Law and the Grant Agreement with the Rockefeller Foundation. The volumes of the Potential natural vegetation of eastern Africa (so far 1-11), is a series serving documentation of the VECEA work, which will be followed by a number of other publications. The use of the map is encouraged. Applications for permission to reproduce or disseminate Forest & Landscape Denmark copyright materials and all other queries on rights should be addressed to FLD. FLD and ICRAF welcome collaboration on further development of the map and utilities from it based on the here published documentation of VECEA as well as additional unpublished material. Forest & Landscape Denmark National centre for research, education and advisory services within the fields of forest and forest products, landscape architecture and landscape management, urban planning and urban design. The report is available electronically from www.ign.ku.dk Introduction This book represents Volume 9 in a eleven-volume series that documents the potential natural vegetation map that was developed by the VECEA (Vegetation and Climate change in East Africa) project. The VECEA map was developed as a collaborative effort that included partners from each of the seven VECEA countries (Ethiopia, Kenya, Malawi, Rwanda, Tanzania, Uganda and Zambia). • In Volume 1, we present the potential natural vegetation map that we developed for seven countries in eastern Africa. In Volume 1, we also introduce the concept of potential natural vegetation and give an overview of different application domains of the VECEA map. • Volumes 2 to 5 describe potential natural vegetation types, also including lists of the “useful tree species” that are expected to naturally occur in each vegetation type – and therefore also expected to be adapted to the environmental conditions where the vegetation types are depicted to occur on the map. Volume 2 focuses on forest and scrub forest vegetation types. Volume 3 focuses on woodland and wooded grassland vegetation types. Volume 4 focuses on bushland and thicket vegetation types. In Volume 5, information is given for vegetation types that did not feature in Volumes 2 to 4. • Volume 6 gives details about the process that we followed in making the VECEA map. • Volume 7 shows the results of modelling the distribution of potential natural vegetation types for six potential future climates. • Volumes 8 to 11 provide a national atlas for four of the seven VECEA countries (Kenya, Rwanda, Tanzania and Uganda). We also provide a summary of the descriptions and species composition of potential natural vegetation types that occur in the species country. We strongly encourage users of the VECEA map to get familiarized with all volumes. For example, as Volume 6 provides a detailed account of the process that we followed in creating the VECEA map, we have not repeated these details in the volumes that provide the national atlases. Erratum (May 18, 2020): Authorships, localities and dates of photographs have been corrected in the figure captions for 9 different photos in volumes 2, 4, 5, 8, 9, 10, and 11. Volume 2 Forest Figures 6.1; 6.2; 20.1 Volume 4 Bushland Figures 4.7; 7.4; 7.5; 7.8 Volume 5 Other Figures 3.5; 4.2; 5.4 Volume 8 Kenya Figures 8.1; 8.2; 16.1; 25.7; 26.4; 26.5; 26.6; 28.5; 29.2; 30.4 Volume 9 Rwanda Figures 7.1; 7.2; 10.1; 14.7; 15.4; 15.5; 15.6; 16.5; 17.2 Volume 10 Tanzania Figures 8.1; 8.2; 16.1, 26.7, 27.4; 27.5; 27.6; 30.5; 31.2 Volume 11 Uganda Figures 8.1; 8.2; 11.1; 20.7; 21.4; 21.5; 21.6; 22.5; 23.2 i Acknowledgements We are extremely grateful to the Rockefeller Foundation for having funded most of the work that has led to the development and publication of the VECEA map and its accompanying documentation. We also greatly appreciate the comments and suggestions that were made by Paul Smith and Jonathan Timberlake (both of Royal Botanic Gardens Kew) when they reviewed early drafts of volumes 2, 3, 4 & 5. Thanks to anybody in our institutions who contributed directly or indirectly to the completion of the VECEA vegetation map and its associated documentation. We especially appreciate the assistance by Nelly Mutio (as for organizing logistics for the regional workshop that we organized in 2009 and for assisting in administrative issues), Melita Jørgensen (for desktop publishing), and of Jeanette van der Steeg for helping with the final preparation of the maps for Volume 1. Thanks to Ann Verdoodt and Eric Van Ranst (both from the University of Ghent) for compiling and sharing thematic soil maps that were derived from the soil of Rwanda (Birasa, E.C., Bizimana, I., Bouckaert, W., Gallez, A., Maesschalck, G., and Vercruysse, J. (1992). Carte Pédologique du Rwanda. Echelle: 1/250.000. Réalisée dans le cadre du projet “Carte Pédologique du Rwanda” (AGCD, CTB). AGCD (Belgique) et MINAGRI, Kigali). Thanks to Eugene Kayijamahe, Center for Geographic Information System and Remote Sensing at National University of Rwanda for sharing the digital map “Vegetation of Volcanoes National Park” that allowed us to classify in greater detail this part of the VECEA map. Thanks to UNEP-GEF for funding the Carbon Benefits Project (CBP) through which information was compiled on indicator and characteristic species for The Vegetation Map of Africa (White 1983). (This work led to the publication in 2011 of an Africa-wide tree species selection tool that is available from: http://www.worldagroforestrycentre.org/our_products/ databases/ useful-tree-species-africa) Thanks to BMZ for funding the ReACCT project in Tanzania through which funding was made available for field verification of the VECEA map around Morogoro (this was essential in preparing the VECEA map as the base map for Tanzania was essentially a physiognomic map. We are grateful for the assistance provided by Meshack Nyabenge (ICRAF) and Jane Wanjara (ICRAF) for digitization of maps. ii Abbreviations Abbreviation Full A Afroalpine vegetation B Afromontane bamboo Bd Somalia-Masai Acacia-Commiphora deciduous bushland and thicket Be Evergreen and semi-evergreen bushland and thicket bi (no capital) Itigi thicket (edaphic vegetation type) br (no capital) C Riverine thicket (edaphic vegetation type, mapped together with riverine forest and woodland) In species composition tables: we have information that this species is a characteristic (typical) species in a national manifestation of the vegetation type D Desert DBH diameter at breast height (1.3 m) E Montane Ericaceous belt (easily identifiable type) In species composition tables: since this species is present in the focal country and since it was documented to occur in the same vegetation type in some other VECEA countries, this species potentially occurs in the national manifestation of the vegetation type Afromontane rain forest Afromontane undifferentiated forest (Fbu) mapped together with Afromontane single-dominant Juniperus procera forest (Fbj) Afromontane single-dominant Widdringtonia whytei forest Zanzibar-Inhambane scrub forest on coral rag (fc, edaphic forest type) Afromontane single-dominant Hagenia abyssinica forest Afromontane moist transitional forest Lake Victoria Euphorbia dawei scrub forest (fe, edaphic forest type mapped together with evergreen and semi-evergreen bushland and thicket) distinct subtype of Afromontane moist transitional forest in Ethiopia distinct subtype of Afromontane moist transitional forest in Kenya Lake Victoria transitional rain forest Zanzibar-Inhambane transitional rain forest Afromontane dry transitional forest Lake Victoria drier peripheral semi-evergreen Guineo-Congolian rain forest Forest & Landscape (URL http://sl.life.ku.dk/English.aspx) Zambezian dry evergreen forest Zambezian dry deciduous forest and scrub forest Zanzibar-Inhambane lowland rain forest Zanzibar-Inhambane undifferentiated forest Zanzibar-Inhambane scrub forest Riverine forests (fr, edaphic forest type mapped together with riverine woodland and thicket) Somalia-Masai scrub forest (Fs, mapped together with evergreen and semievergreen bushland and thicket) Swamp forest (fs, edaphic forest type) Grassland (excluding semi-desert grassland and edaphic grassland, G) Edaphic grassland on drainage-impeded or seasonally flooded soils (edaphic vegetation type, g) f (no capital) Fa Fb Fc fc (no capital) Fd Fe fe (no capital) FeE FeK Ff Fg Fh Fi FLD Fm Fn Fo Fp Fq fr (no capital) Fs fs (no capital) G g (no capital) GCM General Circulation Models GHG greenhouse gas gv ICRAF Edaphic grassland on volcanic soils (edaphic subtype, gv) World Agroforestry Centre (URL http://www.worldagroforestry.org/) IPCC Intergovernmental Panel on Climate Change L M Lowland bamboo Mangrove iii P PROTA S Palm wooded grassland (physiognomically easily recognized type) Plant Resources of Tropical Africa (URL http://www.prota.org/) Somalia-Masai semi-desert grassland and shrubland PNV Potential Natural Vegetation s (no capital) Vegetation of sands (edaphic type) SRES Special Report on Emissions Scenarios T Termitaria vegetation (easily identifiable and edaphic type, including bush groups around termitaria within grassy drainage zones) UNEP VECEA Wb Wc Wcd Wcm WCMC United Nations Environment Programme (URL http://www.unep.org/) Vegetation and Climate Change in Eastern Africa project (funded by the Rockefeller Foundation) Vitellaria wooded grassland Combretum wooded grassland dry Combretum wooded grassland subtype moist Combretum wooded grassland subtype World Conservation Monitoring Centre (URL http://www.unep-wcmc.org/) wd (no capital) Edaphic wooded grassland on drainage-impeded or seasonally flooded soils (edaphic vegetation type) We Wk Wm Wmd Wmr Wmw Biotic Acacia wooded grassland Kalahari woodland Miombo woodland Drier miombo woodland subtype Miombo on hills and rocky outcrops subtype Wetter miombo woodland subtype Wn north Zambezian undifferentiated woodland and wooded grassland (abbreviation: undifferentiated woodland) Wo Mopane woodland and scrub woodland wr (no capital) Riverine woodland (edaphic vegetation type, mapped together with riverine forest and thicket) Wt Terminalia sericea woodland Wvs Vitex - Phyllanthus - Shikariopsis (Sapium) - Terminalia woodland (not described regionally) Wvt Wy X Terminalia glaucescens woodland (not described regionally) Chipya woodland and wooded grassland Fresh-water swamp x (no capital) In species composition tables: we have information that this species is present in a national manifestation of the vegetation type Z ZI Halophytic vegetation Zanzibar-Inhambane coastal mosaic (Kenya and Tanzania coast) iv Contents Introduction Acknowledgements Abbreviations 1. The rationale of the VECEA map 2. Definition of forest, woodland, wooded grassland, bushland and thicket 3. What is potential natural vegetation? 4. Maps of Rwanda 5. Description and species list for Rwanda 5.1. Methodology 6. Afromontane rain forest (Fa) 6.1. Description 6.2. Species composition 7. Afromontane single-dominant Hagenia abyssinica forest (Fd) 7.1. Description 7.2. Species composition 8. Lake Victoria transitional rain forest (Ff) 8.1. Description 8.2. Species composition 9. i ii iii 1 4 5 9 13 13 15 15 17 20 20 22 23 23 24 Lake Victoria Euphorbia dawei scrub forest (edaphic forest type, fe) 28 9.1. Description 28 9.2. Species composition 10. Riverine forests (edaphic forest type, fr) 10.1. Description 29 32 32 10.2. Species composition 32 11. Swamp forest (edaphic forest type, fs) 11.1. Description 37 37 11.2. Species composition 37 12. Biotic Acacia wooded grassland (We) 12.1. Description 40 40 12.2. Species composition 43 13. Palm wooded grassland physiognomically easily recognized type, P 13.1. Description 13.2. Species composition 14. Evergreen and semi-evergreen bushland and thicket (synonym: evergreen bushland, Be) 14.1. Description 14.2. Species composition 15. Montane Ericaceous belt (easily identifiable type, E) 45 45 47 48 48 54 58 15.1. Description 58 15.2. Species composition 61 v 16. Afroalpine vegetation (A) 16.1. Description 16.2. Species composition 17. Afromontane bamboo (B) 17.1. Description 17.2. Species composition 18. Fresh-water swamp (X) 18.1. Description 18.2. Species composition 19. Edaphic grassland on drainage-impeded or seasonally flooded soils (edaphic vegetation type, g) 19.1. Description 19.2. Species composition 20. References vi 62 62 65 66 66 69 70 70 73 74 74 76 79 1. The rationale of the VECEA map The VECEA map of eastern and southern Africa (Ethiopia, Kenya, Uganda, Rwanda, Tanzania, and Zambia) is the product of a project funded by The Rockefeller Foundation and implemented by Forest and Landscape Denmark, World Agroforestry Centre, Nairobi, and botanical experts in the seven countries. The project also benefited from previous support to botanists at the relevant departments at the universities of Makerere/Dar es Salaam by an ENRECA programme provided by Danida and previous support to Ethiopian Flora Project provided by SIDA/SAREC and through grants from the Carlsberg Foundation. The documentation of the VECEA vegetation map consists of seven volumes. In this volume 1, we present the map, and we briefly discuss the important concepts utilised and applied in the map. In volumes 2 to 5, we provide a detailed documentation and discussion of the five major physiognomic vegetation categories and their variation in vegetation types as well as distribution of tree species in this framework. In volume 6, we describe the original maps that we have utilised for each country and we document and discuss the modelling procedures and processes. In volume 7, we model how vegetation types may develop under different climate change scenarios. So why did we chose to make a regional vegetation map when similar maps have already been developed (Olson et al., 2001; Whittaker et al, 2005)? The most recent is the ecoregional approach developed by World Wildlife Fund (WWF), Nature Conservancy, and Conservation International. In WWF’s terrestrial ecoregion scheme(1), White's vegetation map (and memoir) of Africa (White, 1983) - henceforth called the White map - serve as the basis for the ecoregions of the Afrotropics (Olson et al; 2001; Burgess et al. 2004). In this process the ecoregions map has mainly become a simplified version of the White map. A major objective of the White map is to provide a framework on a continental scale within which more detailed local studies can be conducted and compared and as such the map is suitable as a basis for describing the terrestrial ecoregions of Africa by capturing the broad-scale patterns of biological diversity and the ecological processes that sustain them. 1: See also http://www.worldwildlife.org/ science/ecoregions/ecoregion-conservation.html 2: Our method can best be described by paraphrasing the term deconstruction (Derrida, 1967). The White map is an interpretation of reality and we explain it and provide a higher resolution map by revisiting the maps and botanical research that he used to make his map. The VECEA map is thus also an interpretation of reality, but at a higher resolution. We have taken the opposite approach of WWF’s terrestrial ecoregion scheme by deconstructing(2) the White map into its more detailed parts. We have done this by utilising the same smaller maps as those that White utilised and to a large extent described in his text without directly mapping them. The VECEA map thus differs in terms of the spatial resolution, which allows us to break down the landscape into more well defined mapping units. So why do we think that a higher resolution of the map is important? It is in the nature of the scale of the White map (1:5,000,000) that vegetation units on the map are heterogeneous in character and only broadly delineated and thus it is not possible to utilise the White map for a more detailed understanding of vegetation dynamics and species distributions, which is an understanding that is required if a map should be of importance for 1 field implementation (see below for the intended uses of the VECEA map). Furthermore for practically all indigenous species in the region there is insufficient point location data available to make good estimates of their actual and potential distributions across landscapes. A higher resolution of maps and consequently more detailed predictions of species distribution, however, opens up a new discussion of how to interpret vegetation dynamics at the community level (see below for our discussion of Potential Natural Vegetation), but this discussion is unavoidable and necessary for successful field implementation. The great advantage of mapping at a higher resolution is that the interpretation of community dynamics becomes publicly available and can be disputed and tested. This is in contrast to ecoregion maps where managers of restoration projects and tree planters must make their own guesses based on very generalised recommendations. In comparison with White, we have had the advantage of computer based technologies that has enabled us to provide a higher resolution for a very large geographic area. Based on our analysis, we are in overall agreement with White’s methodology and approach and we will provide a detailed discussion of the VECEA map in a number of peer reviewed papers. The process of elaborating the regional map has been iterative. Almost all available relevant vegetation information for the VECEA countries from early 20th century and onwards were collated and digitised. The botanists prepared national maps based on their interpretation of available vegetation maps and botanical information. The preparation of the regional map was a process of harmonisation of nomenclature and interpretation of vegetation types in an interaction between the team members. The main objective for preparing the map is utilitarian and closely related to the requirement for a more detailed understanding of the indigenous tree species in the region – to improve the productivity of smallholder tree growers utilising the species in agroforestry systems. The utility of the map, however, goes beyond understanding the productivity of indigenous tree species and encompasses a more general understanding of agricultural productivity and conservation of fauna and flora in ecosystems. In summary, the utility of the VECEA vegetation map, complemented with additional information on vegetation development and other environmental data layers, is that it: (i) provides an integrated interpretation of landscapes and indicates the position of transitions between areas with significantly different environmental conditions, conditions which are most likely to be important determinative factors for agricultural potential; (ii) predicts potential distributions of indigenous plant species in the agricultural landscapes and predicts possible genetic variation across distributional ranges; (iii) can be a tool for predicting potential distributions of species of terrestrial animals, birds, reptiles, and invertebrates in remaining natural vegetation; 2 (iii) can be a user friendly extension tool for improving the potential options (both from indigenous and exotic species) available to farmers in their quest for improving livelihoods and income generation; (iv) provides for possible forecasts of changes in agricultural potential resulting from climate change; (v) provides a management tool for interpretation of historical, current, and future distribution of ecosystems and ecoregions, including alternative stable states; (vi) provides a tool for ecological restoration and protection of ecosystems. 3 2. Definition of forest, woodland, wooded grassland, bushland and thicket Forests are continuous stands of trees at least 10 m tall with interlocking crowns (White 1983 p. 46). White (1983 p. 46) distinguishes scrub forests that are intermediate in structure between forest and bushland (and thicket). They are usually 10 - 15 m high. Trees (woody plants with well-defined and upright boles) are usually present but do not form a closed canopy. Smaller woody plants (principally bushes and shrubs) contribute at least as much as the trees to the appearance of the vegetation and its phytomass. Woodlands are open stands of trees of at least 8 m tall with a canopy cover of 40 percent or more(1), but never with interlocking crowns and usually with a field layer of heliophilous (‘sun-loving’) grasses. Woodlands have similar height as forests, but woodlands never have densely interlocking crowns (although the crowns can be in contact). White (1983 p. 46) distinguishes scrub woodlands that are intermediate in structure between woodland and bushland, being stunted variants (< 8 m) of main woodland vegetation types (i.e. containing the same dominant tree species). Bushlands are open stands of bushes (usually between 3 and 7 m tall) with a canopy cover of 40 percent or more. Thickets are closed stands of bushes (usually between 3 and 7 m tall) where the bushes are so densely interlaced that they are impenetrable - except along tracks made by animals. Bushlands and thickets are taller than shrublands defined as open or closed stands of shrubs up to 2 m tall (White 1983 p. 46). Wooded grasslands are lands covered with grasses and other herbs with woody plants (trees [≥ 7 m tall], bushes [3 - 7 m], dwarf trees, palm trees or shrubs [≤ 2 m]) covering between 10 and 40 percent of the ground. Woody plants nearly always occur scattered (White 1983 pp. 46, 47 and 52). Grasslands are defined as lands covered with grasses and other herbs and where woody plants do not cover more than 10% of the ground (White 1983 p. 46). Figure 1. Height and cover percentage limits for major physiognomic types. Scrub forest is defined as a physiognomic mosaic of forest and bushland and thicket 4 3. What is potential natural vegetation? We will here attempt to clarify how we interpret and implement terms utilised in the classification of vegetation. The central concept “Potential Natural Vegetation” in the VECEA map can be seen as the pivot around which a whole range of contested assumptions circle. These unavoidable assumptions are concerned with the distribution and dynamics of species and vegetation. While it is indisputable that plants are not randomly distributed geographically and in time, there is an ongoing debate about at what scale patterns can be discerned and whether plant species form assemblies that follow similar distribution patterns. 3: Biome, also called major life zone, the largest geographic biotic unit, a major community of plants and animals with similar life forms and environmental conditions. It includes various communities and is named for the dominant type of vegetation, such as grassland or coniferous forest. Several similar biomes constitute a biome type - for example, the temperate deciduous forest biome type includes the deciduous forest biomes of Asia, Europe, and North America. "Major life zone" is the European phrase for the North American biome concept (http://www.britannica.com, accessed November 14, 2011). Friis (1998) in his review of the development of chorology explains that one of the earliest disputes in botany was about classifying plant distributions (plant chorology). In the beginning of the 19th century J.F. Schouw divided the globe into areas with more or less defined floras. Some of the most important criteria were based on presence or absence of characteristic species and without making assumptions about the historical development of the flora. Some twenty years later in a large work on plant geography A. de Candolle completely rejected a natural classification of the world into phytochoria because. (i) the plant world was too poorly known, and (ii) scientists did not apply sufficiently logical criteria. During the following century many scholars further contributed to the understanding of plant chorology in Africa and there is now a general consensus on chorology as a useful tool to describe plant species distributions in Africa - contrary to the situation in Europe (Friis, 1998). Frank White has been a major contributor and chorological patterns are an important integral part of White’s vegetation map. Although logical, the criteria utilised are still not completely objective in the strictest sense. As Friis points out, White more than once stated that “there is no a priori reasons why the pattern lines on a vegetation map based on physiognomy of vegetation should coincide closely with those of a chorological map based on the coinciding distributional limits of species.” But the results of his work with the vegetation map of Africa showed that if the chorological map of Africa was based on chorological data alone, rather than on transferring pattern lines from a detailed vegetation map, the pattern lines would not have been significantly different” (Friis, 1998 p. 37). Early concepts concerned with the definition of community patterns in space are the biome(3), that was introduced to plant ecology by Clements in the first half of the 20th century and ecoregion that was introduced by Crowley, and Bailey in the second half of the same century (see discussion in Pennington et al., 2004). The concepts are largely overlapping and assume that one can discern broad scale patterns in the distribution of ecological communities, which are defined by similar climax plant formations and environmental conditions. A major difference is that an ecoregion is never discontinuous, while a biome is in principle always coincident with the climax vegetation and therefore can consist of disjunct areas (Bailey, 2005). Biomes 5 and ecoregions define very large scale patterns, thus allowing for analysis at a continental or global scale, and are widely used by conservation agencies. During the first part of the 20th century Clement and later Tansley(4) envisaged that in a given area, the assemblage of plant species would compete and replace each other such that eventually the dominant species would coexist in a stable climax (equilibrium/balance of nature), which would vary with the biotic and abiotic environment including the prevailing climate. This climax concept was soon after contested by Gleason who saw vegetation development as a stochastic process rather than as development as an organism, with communities composed of species with individual adaptations to the biotic and abiotic environment and thus with individual distributions. During the almost one hundred years since these ideas were conceived an enormous amount of studies and theoretical developments have modified our understanding of vegetation dynamics and it is unlikely that any scholar today would understand the term ‘climax vegetation’ in the same way as Clement and Tansley did. Already Whittaker (1962) in a review of the field of vegetation classification largely corroborated Gleason’s view. This concept of the flux of nature led to interest in theories where disturbance is seen as a permanent feature of vegetation such as patch dynamics and patterns and processes in forest (Cadenasso et al., 2003, Whitmore, 1982, van der Maarel, 1996). However, a non-equilibrium view does not preclude that there can be patterns of coinciding distribution of species, such that vegetation types can still be identified (Walker & Del Moral, 2003; Chadzon, 2008). The concept of Potential Natural Vegetation (PNV) is part of this development of vegetation science. A widely accepted definition of PNV is: Potential natural vegetation has been defined as the vegetation structure that would become established if all successional sequences were completed without interference by man under the present climatic and edaphic conditions, including those created by man (van der Maarel, 2005). The term was coined by Tüxen in the middle of the 20th century (Tüxen, 1956) and has been applied in many parts of the world to categorise plant communities. The concept is closely related to the schools of phytosociology, which originated in Europe and elaborated methods for vegetation analysis and detailed and often hierarchical systems of classification of vegetation by floristic and physiognomic characteristics (see reviews by van der Maarel, 2005; Whittaker, 1980). We do not consider the reintroduction of the PNV concept as a statement about the degree of niche assembly of ecological communities versus a stochastic neutral theory (sensu Hubbell, 2008) but as a tangible hypothesis about species distributions. We believe that there is truth in the concepts of climax and PNV as well as in the critique and that for practical conservation and management of vegetation and species this discussion should not only be a theoretical discussion, but should be lead to a more informed interpretation of ‘real’ landscapes. The dichotomy between the continuum concept and the concept of communities as co-occurring species can in principle be solved by considering the two concepts as two different and complementary ways of looking at the same landscape (after Austin, 2005, pp. 66-67): The continuum concept applies to an 6 4: Ecosystem, the complex of living organisms, their physical environment, and all their interrelationships in a particular unit of space. The concept of ecosystems, introduced by Tansley, not only considers the complex of living organisms and their physical environment, but also all their relationships in a particular unit of space (http://www. britannica.com, accessed November 14, 2011). abstract environmental space, not necessarily to any geographical distance on the ground or to any indirect environmental gradient. The abstract concept of community of co-occurring species can only be relevant to a particular landscape and its pattern of environmental variables, community is a property of the landscape. Such a community concept is compatible with the different concepts of a continuum. The PNV map thus offers a useful tool in lieu of missing environmental relationships. For the forests we have been careful not to map the detailed variation of the forest types, but have kept the physiognomic and chorological classification of White (1983). As pointed out by Langdale Brown and Omaston “The forests are characterised by a great variety of species and communities. Sometimes edaphic or seral relationships between these types are clear, but we cannot yet account for all the differences. Indeed these tropical forests are such complex and longlived communities that in many cases it is not yet possible to be sure what is the climax; even the very nature and constancy of the climax is in doubt.” (Langdale Brown & Omaston, 1964 p. 36). The ‘Clementian’ traits of interpreting PNVs are in particular (i) the use of rigid hierarchical systems of classification together with a rigid prescription of species composition, and (ii) a static view that there can be only one endpoint to succession. We suggest that the PNV concept should not be interpreted in terms of a static ‘Clementian’ paradigm and we have been helped in this by the non-hierarchical classification utilised by White. The largest part of the VECEA region is covered by dry vegetation where fire and large browsers (megaherbivores) have profound influence on vegetation development (Bond et al., 2005, Owen-Smith, 1987) and there may in most cases be more than one stable state for the vegetation of a particular area. The use of PNV can thus be an aid in interpreting the dynamics of vegetation and likely alternative stable states. In the Serengeti-Mara area the possibility of alternative stable states has been convincingly documented (Sinclair et al., 2007, McNaughton et al., 1988, Dublin et al., 1990) and the VECEA map could be a tool for identifying alternative stable states in other areas. With the VECEA vegetation map we suggest that the interpretation of landscapes is done at such a resolution that the implications of analyses can be transferred directly to the landscapes. In making a map with this level of detail we have entered the domain of the contested concepts (climax, continuum, species assembly rules, non-equilibrium communities, etc), which may otherwise be avoided at the biome/ecoregional level of analysis (but not in the implementation and management of patterns and processes in actual landscapes). We do not claim that we have completely solved the conundrum with our map, but we trust that we have created a tool that can be an aid in biogeographical analyses. When the concepts, biome, plant community, and PNV are defined very loosely (as they are often used in practice) they are almost interchangeable in the sense that they all attempt to describe the variation in vegetation that can be experienced as one moves through a landscape. The use of the two first concepts is rarely questioned - because of the underlying objectives and the scale at which they are used – as they are rarely utilised in a context 7 where they need to be applied in a particular landscape. PNV on the other hand, by nature of its use to describe plant communities on large scale, immediately invokes an interpretation of pattern and process. Like the concept of chorology, the concept of PNV is logical, but the criteria utilised can not be completely objective in the strictest sense. This is to us an acceptable compromise, since nature includes a large degree of history and chance and we suggest that the PNVs are tested and corroborated through empirical tests as well as modelling. The PNV concept offers a tool that can be utilised in analysing the pattern and processes in landscapes including the biotic and abiotic interrelationships that govern these ecosystem aspects. As such it complements and can be used as an input to modelling of ecosystems and individual species. Although we are confident that the VECEA map provides a realistic picture of where particular vegetation types occur, the map still is a hypothesis about what the actual vegetation type will be. This is an inherent consequence of trying to map anything. 8 4. Maps of Rwanda 9 10 11 12 5. Description and species list for Rwanda 5.1. Methodology For each of the vegetation types, we obtained information on species assemblages (those tree species expected to occur in a particular vegetation type) based on information that was provided in the national references (details are provided in Volumes 2 to 5). For each of the countries where we had information on the national “manifestation” of a vegetation type (for example, Afromontane rain forest as it was described for Ethiopia by Friis et al. 2010), we created a separate column within which we gave an indication that a particular tree species was expected to occur within that vegetation type and within that country. Where species were not listed in the national reference for a focal country, we checked with information on national lists of all the tree species that occur in the focal country whether the species could potentially occur in the focal vegetation type and focal country because the species was documented to occur in the same vegetation type in other countries. For example, the species Cyathea dregei was documented to occur in Afromontane rain forest in Malawi, Rwanda and Zambia. From the UNEP-WCMC species database, there was information that this species also occurs in Ethiopia. This led us to indicate that there was information that the species potentially occurred in Afromontane rain forest in Ethiopia (we used the coding of “f ” in the species assemblage table to indicate this). Note that it is possible that species indicated with “f ” for a particular country and forest type do NOT occur in that particular country and forest type in reality (meaning that, in reality, differences exist between species assemblages of the same forest type between countries – or possibly indicating errors in the obtained species assemblage for a particular country). After compiling information on species assemblages, we selected a subset of species to feature in species composition tables. These were mainly “useful tree species”, which are tree, bushland or liana species that were listed in at least one of the references that we consulted on tree species that are expected to be useful to farming or pastoral communities in the VECEA countries Information that is provided in species composition tables was simplified from the information provided in Volumes 2 to 5, providing the following types of information: ◦ “x” in a species composition tables indicates that the species is expected to occur in the vegetation type based on references that we consulted or field experience from a national collaborator ◦ “C” in a species composition table indicates that the species is a characteristic species for the vegetation type (see Volumes 2 to 5 for details) 13 ◦ “f ” in a species composition table indicates that the species was not initially listed for the country, but could potentially occur because the species is known to occur in that particular country ◦ A “characteristic species” is a species that was listed for the focal vegetation type in a regional description of potential natural vegetation (this regional description was typically White 1983) ◦ A species that is “not characteristic” is a species that was not listed for the focal vegetation type in a regional description of potential natural vegetation ◦ An “indicator species” was defined as a characteristic species that was only listed once (i.e. for the focal vegetation type) among all the vegetation types of the same physiognomic classification and the same floristic region. For example, Chrysophyllum gorungosanum is an indicator species for Afromontane rain forest since this species was only listed for Afromontane rain forest (White 1983 p. 164) among all the forests described for the Afromontane floristic region. Another modification from the species composition tables that were given in Volumes 2 to 5 is that we excluded species that were listed to be present (coding “x” or “C”) in fewer than 50 percent of all the countries in which the vegetation type occurs. We implemented this change to increase consensus among national manifestations of the focal vegetation type (and especially to filter out marginal occurrence of a species), and also to increase confidence about the regional occurrence of a species. Although this approach has led to better agreements between national documentation, we may have excluded some species that widely occur in some situations (please compare the abbreviated lists provided here with the more comprehensive lists provided in Volumes 2 to 5 if you are particularly interested in these species). 14 6. Afromontane rain forest (Fa) 6.1. Description Afromontane rain forest is very similar in structure (physiognomy) to certain types of Guineo-Congolian rain forest. Species composition, however, is almost entirely different (many tree genera have different species in Afromontane rain forest and Guineo-Congolian rain forest, on the other hand). Other physiognomic and floristic differentiation between Afromontane rain forest and Guineo-Congolian rain forest include the greater degree of bud protection, a lesser degree of drip tips of leaves development, the occurrence of tree ferns (Cyathea) and the occurrence of conifers (Podocarpus; especially Podocarpus latifolius as Podocarpus falcatus (synonym: P. gracilior) are more characteristic of Afromontane undifferentiated forest; White 1983 p. 164 - 165). These forests occur mainly between 1200 and 2500 m on the slopes of certain mountains. However, the altitudinal limits vary greatly according to distance from the equator, proximity to the ocean, and size and configuration of the massif on which these forests occur (White 1983 p. 164). The observation that vegetation belts are scaled according to the size of the mountain on which they occur were first observed in the Alps, where this phenomenon is described as the ‘Massenerhebung effect’ (mass-elevation effect). The mean annual rainfall lies mostly between 1250 and 2500 mm. Mists that frequently occur during the dry season of one to five months may explain the fact that Afromontane rain forest is much less deciduous than lowland semi-evergreen forests that receive similar rainfall. Only a few of the larger tree species (Entandophragma excelsum and Pouteria adolfi-friedericii) lose their leaves - and then only for a few days (White 1983 p. 164). Regional indicator species (characteristic species listed by White (1983) [1983] that were only provided for Afromontane rain forest and no other Afromontane forest types) that were listed as characteristic species for one or several national maps include Chrysophyllum gorungosanum, Cola greenwayi, Cylicomorpha parviflora, Entandrophragma excelsum, Ficalhoa laurifolia, Hallea rubrostipulata, Myrianthus holstii, Ochna holstii, Ocotea usambarensis, Olea capensis, Parinari excelsa, Pouteria adolfi-friedericii, Strombosia scheffleri, Syzygium guineense subsp. afromontanum and Tabernaemontana stapfiana. 15 Figure 6.1. View of canopy from Afromontane rain forest (synonym: moist evergreen Afromontane forest) north of Masha (Ethiopia). Altitude approximately 1950 m. Photograph by I. Friis and Sebsebe Demissew (September 2002). Reproduced from Biologiske Skrifter of the Royal Danish Academy of Sciences and letters, Vol. 58, Fig 25A. 2010. Figure 6.2. Afromontane rain forest in Nyungwe National Park (Rwanda). Photograph by C. K. Ruffo (June 2008). Figure 6.3. Cyathea manniana tree ferns in Lake Victoria transitional rain forest (Ff). The presence of tree ferns (Cyathea species) is typical for Afromontane rain forest (White 1983 p. 164). However, this species also occurs in other types of forests with admixture of Afromontane species. Photograph by F. Gachathi (2009). 16 Figure 6.4. Transect of Primary or mature secondary moist evergreen Afromontane forest (classified in VECEA as Afromontane rain forest [Fa]). Generalised representation based on observations made in old secondary forest at approximately 1700 metres altitude south of Gore, IL floristic region. Although this locality is situated just below the altitudinal limit used for mapping (6) Moist evergreen Afromontane forest (Fa) no species restricted to (7) Transitional rain forest (mapped in VECEA as Afromontane moist transitional forest [Fe]) were observed, but a few species, for example Hallea rubrostipulata, are known from both vegetation types. The abbreviated names for the species stand for: Aa: Pouteria (Aningeria) adolfifriederici. As: Albizia schimperiana. CRm: Croton macrostachyus. CYm: Cyathea manniana. Da: Dracaena afromontana. Ds: Dracaena steudneri. Eo: Euphorbia ampliphylla. Ev: Enset ventricosum. Fs: Ficus sur. Lg: Lobelia giberroa. Mf: Millettia ferruginea. Mk: Macaranga capensis var. kilimandscharica. Mr: Hallea (Mitragyna) rubrostipulata. Pa: Prunus africana. Pf: Polyscias fulva. Pr: Phoenix reclinata. Sa: Schefflera abyssinica. Sa: Sapium ellipticum. Drawn by Victoria C. Friis. Reproduced from Biologiske Skrifter of the Royal Danish Academy of Sciences and letters, Vol. 58, Fig 24. 2010. 6.2. Species composition (Please check the methodology and information from Volumes 2 - 5 for more details on how the information on species composition for the different manifestations of this potential natural vegetation type was compiled. In composition tables, "x" indicates that the species is expected to be present, "C" indicates that the species was identified as characteristic species and "f" indicates a species that was not listed in the documentation that we consulted although it is known to occur in the specific country). 17 Podocarpus latifolius Prunus africana Xymalos monospora Acacia abyssinica Acacia lahai Agauria salicifolia Albizia grandibracteata Albizia gummifera Albizia schimperiana Alchornea hirtella Allophylus abyssinicus Allophylus africanus Anthocleista grandiflora Apodytes dimidiata Balthasaria schliebenii Berberis holstii Bersama abyssinica Blighia unijugata Bridelia brideliifolia Carapa procera Casearia battiscombei Cassipourea malosana Cassipourea ruwensoriensis Catha edulis Celtis africana Celtis gomphophylla Clausena anisata Cordia africana Cornus volkensii Croton macrostachyus Croton megalocarpus Croton sylvaticus Cussonia spicata Cyathea dregei Cyathea humilis Cyathea manniana Discopodium penninervium Dodonaea viscosa Dombeya torrida Dovyalis abyssinica Dovyalis macrocalyx Dracaena fragrans Dracaena steudneri Ehretia cymosa Ekebergia capensis Elaeodendron buchananii Embelia schimperi Ensete ventricosum Eugenia capensis Euphorbia abyssinica Fagaropsis angolensis Ficus exasperata Ficus natalensis Ficus ovata Ficus sur 18 not characteristic C C C x not characteristic x x f f f x x x C x x x f x C C f C C x x x C C f C x x C x C x x f C C x x C f x C f f C f x x C f not characteristic C C C f x x f f C C C not characteristic tree fern that is characteristic of Afromontane rain forest and that is absent from Guineo‐Congolian rain forest tree fern that is characteristic of Afromontane rain forest and that is absent from Guineo‐Congolian rain forest tree fern that is characteristic of Afromontane rain forest and that is absent from Guineo‐Congolian rain forest C C x x C C C C C C C C C x x x C f x C C C C C x f not characteristic x x C C C x C C x f x x C C C f C C x x f x C x x x C x f x x f x f C C x x f C x x f C C C f x f f C f x x f C x x x x x x x x x C x x x x x x f x x x f f f f C f f C C C f C f f f f C f C C f f f f f C f C C x x f f f x x x f f x x x x x f x C x x f f f f x f f f f x f f f f x f f x f f f f f f f f f f f x f f f f C x C f f x f f f f f f f f C f x f C f f C f f f f f f f f f f f f f f f f f f f f f f f f f f C f f f f f f f f f f f f f f f f f f f f f f f f f f C C x x f x x f C C C f f f x f x x x x x x f f x f Zambia x C C x C C x x x C C C C C x x x Uganda C C C C Tanzania (FawT subtype) indicator species indicator species indicator species indicator species indicator species indicator species indicator species indicator species indicator species indicator species indicator species indicator species indicator species indicator species (Syzygium guineense ssp. afromontanum ) indicator species characteristic species characteristic species (conifer species that is absent from Guineo‐Congolian rain forest, but more characteristic of other types of Afromontane forest) characteristic species characteristic species invasive species invasive species Rwanda Chrysophyllum gorungosanum Cola greenwayi Cylicomorpha parviflora Entandrophragma excelsum Ficalhoa laurifolia Hallea rubrostipulata Myrianthus holstii Ochna holstii Ocotea usambarensis Olea capensis Parinari excelsa Pouteria adolfi-friedericii Strombosia scheffleri Syzygium guineense Tabernaemontana stapfiana Diospyros abyssinica Tanzania (FarT subtype) Regional status Kenya SPECIES Malawi Ethiopia Table 6. Species composition of Afromontane rain forest (Fa) x x x x x f x x x f x x x x x x f f C C x f f f f C f f x f x f f C f f f f x f f f f x f f x f f x f f f f C C f f C f f C f f f f f f f f f f f f f f f f f f f C f f x f f f x f x f f f f x f f f f f f f f f f f f f f f f f f f f f C f C f x x Zambia C x f C f x C Uganda Malawi Rwanda C C x C C f x C f C C C x C x x x C x C f C C f x x x x x x Tanzania (FarT subtype) Podocarpus usambarensis Polyscias fulva Pouteria altissima Psychotria mahonii Psydrax parviflora Pterolobium stellatum Rapanea melanophloeos Rauvolfia caffra Rhamnus prinoides Rinorea angustifolia Ritchiea albersii Rothmannia urcelliformis Rubus apetalus Sambucus ebulus Schefflera abyssinica Schefflera volkensii Scutia myrtina Shirakiopsis elliptica Sinarundinaria alpina Smilax anceps Solanecio mannii Solanum aculeastrum Symphonia globulifera Synsepalum brevipes Syzygium cordatum Tabernaemontana pachysiphon Trema orientalis Trichilia dregeana Vangueria apiculata Vepris nobilis Vernonia auriculifera Vernonia myriantha Vitex keniensis Zanthoxylum gilletii C x x f Tanzania (FawT subtype) Podocarpus henkelii Kenya Ficus thonningii Galiniera saxifraga Garcinia buchananii Hagenia abyssinica Harungana madagascariensis Hypericum revolutum Ilex mitis Kigelia moosa Landolphia buchananii Lepidotrichilia volkensii Macaranga capensis Maesa lanceolata Manilkara butugii Maytenus acuminata Maytenus undata Milicia excelsa Millettia dura Neoboutonia macrocalyx Newtonia buchananii Nuxia congesta Nuxia floribunda Ocotea kenyensis Olea europaea Olinia rochetiana Peddiea fischeri Phoenix reclinata Phytolacca dodecandra Pittosporum viridiflorum Pleiocarpa pycnantha Podocarpus falcatus Ethiopia SPECIES f f f f f f C f f f C C x x f f C x x x x f x x f f x x C f f f f x x f f f f f f f f f f C C f f f f f C f x f x f f f x f f f C x f f f x f f C C x f x f f f x f f f f f f f f f C f f f x C x f f f f f f f f f f x f f x f f f f f x f f f f f f f f f f f f f f f f f x f C f f x f x f f f f f x C f f x f f f C f x x x x f f f f f f f f f f x f f C f f f f f f f f f f f f f f f C f C f f f f f f f x f f f Regional status not characteristic f C x x f x x x f not characteristic not characteristic not characteristic not characteristic not characteristic x C f f palm species x f x not characteristic conifer species that is absent from Guineo‐Congolian rain forest, but more characteristic of other types of Afromontane forest; species that is very localized north of the Limpopo river conifer species that is absent from Guineo‐Congolian rain forest, but more characteristic of other types of Afromontane forest x f f f x x x f Afromontane bamboo C x x x C f x x x x x x x x x f f f C f f f f f f f f f f f f f C C f not characteristic x x C f f f f f f C x f C C x x x x f x x x f x f f C C x C f x x x f x x C C x x f x f x C x x x C x x x x C f x x f x x x x x C x x x x x C f C x x f C x x C C f f f x x x f x x x f x C x f f f f f f f f C f f f f f f f f f f f f f f f f f f f f f f f 19 7. Afromontane single-dominant Hagenia abyssinica forest (Fd) 7.1. Description Hagenia abyssinica is found on most of the higher mountains between Ethiopia and northern Malawi, including Mt. Kenya, Mt. Meru (Tanzania), the Nyika Plateau (Malawi) and the Virunga mountains (Rwanda). Characteristically, Hagenia abyssinica forms almost pure stands of 9 to 15 m tall in a narrow and often interrupted zone between the montane Ericaceous belt (E) and taller types of Afromontane rain forest (Fa) or Afromontane undifferentiated forest (Fbu). The best-developed stands are clearly forest, but other stands have a structure that is better described as woodland or scrub forest (White 1983 p. 166). Some authors have suggested that Afromontane single-dominant Hagenia abyssinica forest is a climax vegetation type where low night temperatures exclude other trees. However, even at high altitudes the dominance of Hagenia abyssinica is probably still the result from disturbance. The altitudinal range of this species is between 1800 and 3400 m. The abundance of this species does not seem to be related to moisture conditions, although the species is usually absent from Afromontane rain forest (Fa) and taller types of Afromontane undifferentiated forest (White 1983 p. 166). 20 Figure 7.1. Afromontane singledominant Hagenia abyssinica forest between the Karisimbi and Bisoke volcanoes in the Volcanoes National Park (Rwanda). Photograph by E. Fischer (October 1991) Figure 7.2. Flowering Hagenia abyssinica tree against a background of Afromontane bamboo (Sinarundinaria alpina, synonym: Arundinaria alpina) n Kahuzi-Biega National Park (D.R.Congo). Hagenia abyssinica is also present in other types of Afromontane forest such as Afromontane singledominant Juniperus procera forest (Fbj). Photograph by E. Fischer (October 1991).(Rwanda). 21 7.2. Species composition (Please check the methodology and information from Volumes 2 - 5 for more details on how the information on species composition for the different manifestations of this potential natural vegetation type was compiled. In composition tables, "x" indicates that the species is expected to be present, "C" indicates that the species was identified as characteristic species and "f" indicates a species that was not listed in the documentation that we consulted although it is known to occur in the specific country). 22 D f x C C x x C C C x C f C x C C C f f f f f f f f C f C f f f C f f f f f f f f Uganda not characteristic C C f f D f f f Rwanda dominant indicator species characteristic species characteristic species characteristic species (species that does not extend as far north as Ethiopia) characteristic species characteristic species characteristic species (species that does not extend as far north as Ethiopia) characteristic species characteristic species characteristic species (species that does not extend as far north as Ethiopia) not characteristic Tanzania Hagenia abyssinica Hypericum revolutum Apodytes dimidiata Ilex mitis Kiggelaria africana Nuxia congesta Nuxia floribunda Podocarpus latifolius Prunus africana Rapanea melanophloeos Xymalos monospora Cassipourea malosana Cornus volkensii Cussonia spicata Lepidotrichilia volkensii Olea capensis Olinia rochetiana Pittosporum viridiflorum Schefflera volkensii Kenya Regional status Ethiopia (FbuE subtype) SPECIES Malawi Table 7. Species composition of Afromontane single-dominant Hagenia abyssinica forest (Fd) D C f f D f f f f f f f f f f f f f f f f f f C x f f f f f f f f f f f f f f f f x x f f C f f f f f f 8. Lake Victoria transitional rain forest (Ff) 8.1. Description White describes two types of Lake Victoria transitional rain forest: (i) transitional rain forests occurring between 1600 and 1900 m in western Burundi, western Rwanda and eastern Kivu (DRC); and (ii) Kakamega forest in Kenya (1520 to 1680 m). Kakamega forest is described as containing a mixture of Guineo-Congolian lowland rain forest species (that reach their easternmost limits in distribution in Kakamega forest) and Afromontane species, but containing fewer Afromontane species than the other Lake Victoria transitional rain forests (White 1983 p. 181). Regional indicator species (characteristic species listed by White (1983) [1983] that were only provided for Lake Victoria transitional rain forest and no other Lake Victoria forest types) that were listed as characteristic species for one or several national maps include Alangium chinense (Afromontane species, also a indicator for Zanzibar-Inhambane transitional rain forest [Ff]), Anthonotha pynaertii, Apodytes dimidiata (Afromontane species, also characteristic of Afromontane undifferentiated forest [Fbu] and Afromontane dry transitional forest [Fh]), Carapa procera, Chrysophyllum gorungosanum (also a indicator of Afromontane rain forest [Fa]), Cordia millenii (Guineo-Congolian lowland rain forest species), Diospyros gabunensis, Macaranga capensis (synonym: Macaranga kilimandscharica; Afromontane species), Monodora myristica (Guineo-Congolian lowland rain forest species), Neoboutonia macrocalyx (Afromontane species), Newtonia buchananii (also a characteristic species of Afromontane moist transitional forest [FeK], Afromontane dry transitional forest [Fh; near streams], ZanzibarInhambane lowland rain forest [Fo] and Zanzibar-Inhambane transitional rain forest [Fg; upland species]), Parinari excelsa (also an indicator of Afromontane rain forest [Fa]), Prunus africana (Afromontane species, also characteristic of Afromontane rain forest [Fa] and Afromontane undifferentiated forest [Fbu]), Strombosia scheffleri (Afromontane species, also a indicator of Afromontane rain forest [Fa]), Symphonia globulifera, Syzygium guineense (also an indicator of Afromontane rain forest [Fa]), Turraea holstii (Afromontane species) and Xymalos monospora (also characteristic of Afromontane rain forest [Fa] and Afromontane undifferentiated forest [Fbu]). 23 Figure 8.1. Profile diagram of Lake Victoria transitional rain forest in Burundi. Although White (1983 p. 164) listed this profile diagram for the description of Afromontane rain forest (Fa), the altitude range for this forest type of 1600 – 1900 m were described by White (1983 p. 181) for Lake Victoria transitional rain forest (Ff) and also corresponded to the altitude range of the “horizon inférieur” mentioned with the original publication of this profile diagram, Lewalle (1972, Fig. 21). Figure obtained from URL: http://www.jstor.org/stable/3667406. Figure 8.2. Lake Victoria transitional rain forest in South Nandi forest. Photograph by F. Gachathi. 8.2. Species composition (Please check the methodology and information from Volumes 2 - 5 for more details on how the information on species composition for the different manifestations of this potential natural vegetation type was compiled. In composition tables, "x" indicates that the species is expected to be present, "C" indicates that the species was identified as characteristic species and "f" indicates a species that was not listed in the documentation that we consulted although it is known to occur in the specific country). 24 Regional status Alangium chinense Anthonotha pynaertii Apodytes dimidiata Carapa procera Chrysophyllum gorungosanum Cordia millenii Diospyros gabunensis Macaranga capensis Monodora myristica Neoboutonia macrocalyx Newtonia buchananii Parinari excelsa Prunus africana Strombosia scheffleri Symphonia globulifera Syzygium guineense Turraea holstii Xymalos monospora Albizia gummifera Entandrophragma angolense Maesopsis eminii Pouteria altissima Acacia abyssinica Acacia lahai Acacia mearnsii Agauria salicifolia Albizia grandibracteata Albizia zygia Alchornea hirtella Allophylus abyssinicus Allophylus rubifolius Anthocleista grandiflora Antiaris toxicaria Antidesma venosum Beilschmiedia ugandensis Bersama abyssinica Blighia unijugata Bridelia brideliifolia Bridelia micrantha Buddleja polystachya Caesalpinia decapetala Caesalpinia volkensii Casearia battiscombei Cassipourea malosana Cassipourea ruwensoriensis Celtis africana Celtis gomphophylla Celtis mildbraedii Chrysophyllum albidum Clausena anisata Cordia africana Craibia brownii Crotalaria agatiflora Croton macrostachyus Croton megalocarpus Croton sylvaticus Cyathea manniana Diospyros abyssinica Dombeya torrida Dovyalis abyssinica Dovyalis macrocalyx Dracaena fragrans Dracaena steudneri indicator species (Afromontane species) indicator species indicator species (Afromontane species) indicator species indicator species (Afromontane species) indicator species (Guineo‐Congolian species) indicator species indicator species (Afromontane species) indicator species (Guineo‐Congolian species) indicator species (Afromontane species) indicator species indicator species (Afromontane species) indicator species (Afromontane species) indicator species (Afromontane species) indicator species indicator species (Afromontane species [Syzygium guineense ssp. afromontanum ]) indicator species (Afromontane species) indicator species (Afromontane species) characteristic species characteristic species (Guineo‐Congolian species) characteristic species (Guineo‐Congolian species) characteristic species (Guineo‐Congolian species) not characteristic not characteristic Rwanda SPECIES Kenya Table 8. Species composition of Lake Victoria transitional rain forest (Ff) x f x x C C x f C x C C f x C x C x C C C C x x f f C C x x x C C x x C C C x x x C C C x C C C x C x x C C C x C x x x x C x x C C C x x C x x C f x f x x f x x f f f f x f f x f C C f f f x x x f x x f x 25 26 Rwanda Ehretia cymosa Ekebergia capensis Embelia schimperi Ensete ventricosum Entada abyssinica Entandrophragma excelsum Eugenia capensis Fagaropsis angolensis Ficalhoa laurifolia Ficus exasperata Ficus natalensis Ficus sur Ficus thonningii Funtumia africana Galiniera saxifraga Garcinia buchananii Hagenia abyssinica Harungana madagascariensis Hypericum revolutum Ilex mitis Kigelia africana Kigelia moosa Lecaniodiscus fraxinifolius Lepidotrichilia volkensii Lovoa trichilioides Maesa lanceolata Manilkara butugii Margaritaria discoidea Markhamia lutea Maytenus acuminata Maytenus undata Milicia excelsa Mimusops bagshawei Mimusops kummel Mondia whitei Morus mesozygia Nuxia congesta Nuxia floribunda Ocotea kenyensis Ocotea usambarensis Olea capensis Olinia rochetiana Peddiea fischeri Phoenix reclinata Phytolacca dodecandra Pittosporum viridiflorum Plectranthus barbatus Pleiocarpa pycnantha Podocarpus falcatus Podocarpus latifolius Polyscias fulva Pouteria adolfi‐friedericii Pseudospondias microcarpa Psychotria mahonii Psydrax parviflora Pterolobium stellatum Rapanea melanophloeos Rhamnus prinoides Rinorea angustifolia Ritchiea albersii Rothmannia urcelliformis Rubus apetalus Rubus volkensii Regional status Kenya SPECIES C C x f x C x x x f C x x x x f x f f C C x C C C x C x C f f f C C x not characteristic not characteristic (palm species) x C x C f x C C C x C C f f f C f f x x x x f f f C x C x C x x x f x C x x x f x C x x x x x x f x x f f x x x x f x x f f x x x x x f x x f f x x x x x Schefflera abyssinica Schefflera volkensii Schrebera alata Scutia myrtina Senna didymobotrya Senna septemtrionalis Shirakiopsis elliptica Smilax anceps Solanum aculeastrum Spathodea campanulata Sterculia dawei Tabernaemontana pachysiphon Tabernaemontana stapfiana Trema orientalis Trichilia dregeana Trichilia emetica Trilepisium madagascariense Vangueria apiculata Vepris nobilis Vernonia amygdalina Vernonia auriculifera Vernonia myriantha Warburgia ugandensis Zanthoxylum gilletii Zanthoxylum rubescens x x fh x x x C f x C x C x C C C C f C x x x C C C Rwanda Regional status Kenya SPECIES x f f f C x x f x x x x f f x x 27 9. Lake Victoria Euphorbia dawei scrub forest (edaphic forest type, fe) 9.1. Description Vegetation intermediate between rain forest and evergreen bushland (Be) probably occurred more extensively in the Lake Victoria basin than in other parts of Africa, but only few relicts remain (White 1983 p. 182). White (1983 p. 182) describes the following types of Lake Victoria scrub forests: (i) Cynometra-Euphorbia scrub forest in Burundi and Uganda; (ii) Euphorbia dawei scrub forest in the basin of Lake Edward; (iii) Euphorbia dawei scrub forest in the Ruzizi valley and (iv) tall scrub forest in the Ruzizi valley (White 1983 p. 182): • Cynometra-Euphorbia scrub forest in Burundi and Uganda is characterized by 10 m tall Cynometra alexandri (also a characteristic species of Lake Victoria drier peripheral semi-evergreen Guineo-Congolian rain forest [Fi]) and is usually associated with Euphorbia dawei. • Euphorbia dawei scrub forest in the basin of Lake Edward (0º 21’ S; 29º 37’ E) forms forests have canopies of 12 to 15 m; they occur at 900 to 1000 m altitude in bands up to 3 km wide along the banks of rivers and on the lower slopes of escarpments. • Euphorbia dawei forms scrub forests only in a single locality in the Ruzizi valley where Euphorbia dawei occurs as a 17 to 18 m high emergent above a 10 to 12 m canopy of Cynometra alexandri and Tamarindus indica. This formation is described as the Burundian ‘La forêt sclérophylle à Euphorbia dawei’ forest type by Lewalle (1972 p. 57, see below). • Tall scrub forest of 15 m high is expected to be the climax community in the Ruzizi valley and consists of an upper canopy of Albizia grandibracteata, Euphorbia candelabrum, Grewia mollis, Strychnos potatorum and Tamarindus indica. This formation is described as the ‘La forêt sclérophylle à Strychnos potatorum’ forest type by Lewalle (1972 p. 57) and as ‘La forêt tropophile à Albizia grandibracteata et Strychnos potatorum ‘ forest type by Germain (1955 p. 41). We classified Euphorbia dawei scrub forest as an edaphic vegetation type based on the suggestion that this vegetation type is especially restricted to rocky slopes, whereas evergreen bushland (Be) would be the climax vegetation type elsewhere (White 1983 p. 183). Besides the potentially dominant Cynometra alexandri and Euphorbia dawei, regional indicator species (characteristic species listed by White (1983) that were only provided for Lake Victoria Euphorbia dawei scrub forest and no other Lake Victoria forest types, include Cissus quadrangu28 laris (liana species), [Olea europaea subsp. cuspidata, (synonym: Olea africana; also a indicator for Afromontane dry transitional forest [Fh]) and Psydrax parviflora. Figure 9.1. Profile diagram of Lake Victoria Euphorbia dawei scrub forest in Burundi. Lewalle (1972, Fig.15). Image obtained from URL: http://www.jstor.org/stale/3667406 9.2. Species composition (Please check the methodology and information from Volumes 2 - 5 for more details on how the information on species composition for the different manifestations of this potential natural vegetation type was compiled. In composition tables, "x" indicates that the species is expected to be present, "C" indicates that the species was identified as characteristic species and "f" indicates a species that was not listed in the documentation that we consulted although it is known to occur in the specific country). 29 Baikiaea insignis Barringtonia racemosa Beilschmiedia ugandensis Blighia unijugata Bridelia micrantha Canarium schweinfurthii Celtis africana Celtis gomphophylla Clausena anisata Combretum imberbe Cordia africana Cordyla africana Craterispermum laurinum Croton megalocarpus Diospyros mespiliformis Dombeya rotundifolia Dracaena camerooniana Ekebergia capensis Elaeis guineensis Erythrina abyssinica Erythrina excelsa Erythrophleum suaveolens Erythroxylum fischeri Euclea divinorum Faidherbia albida Ficalhoa laurifolia Ficus natalensis Ficus sur Ficus sycomorus Ficus trichopoda Ficus vallis‐choudae Flueggea virosa Funtumia africana Garcinia smeathmannii Gardenia imperialis Hallea stipulosa Hibiscus tiliaceus Ilex mitis Khaya anthotheca Kigelia africana Klainedoxa gabonensis Lannea schweinfurthii Lecaniodiscus fraxinifolius Macaranga monandra Macaranga schweinfurthii Macaranga spinosa Maesa lanceolata Maesopsis eminii Musanga cecropioides Newtonia buchananii Parinari excelsa 30 Afromontane species in forests on alluvial deposits at the mouth of the Kagera river Zambezian swamp forest Guineo‐congolian species in forests on alluvial deposits at the mouth of the Kagera river (dominant) Zanzibar‐Inhambane swamp forest, also mangrove associated species Guineo‐congolian species in forests on alluvial deposits at the mouth of the Kagera river f C f f f f f f f f f f f f f f f f f Zambezian swamp forest riparian forest in the greater Serengeti region Zanzibar‐Inhambane swamp forest (palm species) Zambezian deciduous riparian forest Somalia‐Masai, Sudanian and Zambezian deciduous riparian forest Lake Victoria swamp forest; Zambezian swamp forest f f Zambezian swamp forest Zambezian swamp forest Lake Victoria swamp forest; Zambezian swamp forest Zanzibar‐Inhambane swamp forest, also mangrove associated species Afromontane species in forests on alluvial deposits at the mouth of the Kagera river; Zambezian swamp forest Somalia‐Masai and Zambezian evergreen or semi‐evergreen riparian forest Somalia‐Masai and Zambezian deciduous riparian forest Guineo‐congolian species in forests on alluvial deposits at the mouth of the Kagera river f f C C x f f f f f f x f f x f f f f f f f D f x x x f C f C f x f f C f f f C x f f x f f C f x f f f f x f f f x f f x f f f f f f f f f C f f f f f f f f f f f f f x f x f x x f x f f f x x x f f x x f f f f f f f f f f f f f f x f f f f f C f x f f C C f f f f f f f C C f C C x f f f f f f f x f f f f f x C f f f f x C C f x f Somalia‐Masai (including greater Serengeti region) and Zambezian deciduous riparian forest Lake Victoria swamp forest Lake Victoria swamp forest Lake Victoria swamp forest x f x C f f x f f x f f f x x f f f f f C f C f C f f f f f f f f f f f x f f f f f x x f f f x x C x f f f f f f f f f C f f f C f f x f f f f f f f f f f f C f x x x f f f f f x f x f f x x f f f f f f f f f x f f f C C f Guineo‐congolian species in forests on alluvial deposits at the mouth of the Kagera river Lake Victoria swamp forest Zambezian evergreen or semi‐evergreen riparian forest; near streams in Afromontane dry transitional forest f C f f f f f x x f x f C f f f f f f f f f f f f f f f f f C f C Lake Victoria swamp forest Zambezian evergreen or semi‐evergreen riparian forest C C f f f f f f f f f C f f f f f f f f f f f Zambezian deciduous riparian forest Zambezian deciduous riparian forest Zambezian swamp forest Afromontane species in forests on alluvial deposits at the mouth of the Kagera river Somalia‐Masai, Sudanian and Zambezian deciduous riparian forest f f x f Coast Kenya f f C Zambia Apodytes dimidiata Aporrhiza nitida Lake Victoria swamp forest f Uganda (fsrU subtype) Lake Victoria swamp forest Zanzibari‐Inhambane swamp forest (fern species) Somalia‐Masai riparian forest Uganda (fsbU subtype) Acacia kirkii Acrostichum aureum Albizia glaberrima Alchornea hirtella Anthocleista grandiflora Anthocleista schweinfurthii Antidesma venosum Rwanda Regional status Tanzania SPECIES Malawi Ethiopia Table 9. Species composition of Lake Victoria Euphorbia dawei scrub forest (edaphic forest type, fe) f x f f C f f f f f f Strombosia scheffleri Strychnos mitis Symphonia globulifera Syzygium cordatum Syzygium guineense Syzygium owariense Terminalia sambesiaca Tetrapleura tetraptera Trichocladus ellipticus Typhonodorum lindleyanum Uapaca guineensis Vangueria madagascariensis Vepris nobilis Vitex doniana Voacanga thouarsii Warburgia ugandensis Xylopia aethiopica Xylopia rubescens Ziziphus pubescens Zambia Coast Pycnanthus angolensis Raphia farinifera Rauvolfia caffra Ritchiea albersii Rothmannia urcelliformis Schrebera arborea Scutia myrtina Shirakiopsis elliptica Sorindeia madagascariensis Spondianthus preussii Sterculia tragacantha Uganda (fsrU subtype) Pseudospondias microcarpa Psychotria mahonii Psychotria peduncularis Pterocarpus tinctorius Uganda (fsbU subtype) Podocarpus usambarensis Rwanda Podocarpus latifolius Tanzania Podocarpus falcatus x x f f f x f x f f f C x x f f f f f f f f x f D f f D f f f f C x x f f f f f f f f f x x x x x x x x f f D f x C f f C f Kenya Phoenix reclinata f f Malawi Parkia filicoidea Peddiea fischeri f C f f C f f Ethiopia SPECIES Regional status Lake Victoria swamp forest (also Somalia‐Masai and Zambezian evergreen or semi‐evergreen riparian forest) Lake Victoria swamp forest; Zanzibar‐Inhambane swamp forest; palm species Afromontane species in forests on alluvial deposits at the mouth of the Kagera river Afromontane species in forests on alluvial deposits at the mouth of the Kagera river Afromontane species in forests on alluvial deposits at the mouth of the Kagera river (dominant [Podocarpus usambarensis var. dawei ]) Lake Victoria swamp forest; Guineo‐congolian species in forests on alluvial deposits at the mouth of the Kagera river f C C f Zambezian swamp forest Guineo‐congolian species in forests on alluvial deposits at the mouth of the Kagera river Lake Victoria swamp forest (palm species) f f f f f f f C f f f x f f f C f f f f f x C f C C Sudanian riparian forest Lake Victoria swamp forest; Zanzibar‐Inhambane swamp forest Afromontane species in forests on alluvial deposits at the mouth of the Kagera river Zambezian swamp forest Zambezian swamp forest f f f f f C f f D f D f f f f f f f C f f C f f f f f f f f f C f f f C C f f f x f f f f x f f f x f f f f f f C x f x f f x f f f C x f f f f x f f f f f f Lake Victoria swamp forest Afromontane species in forests on alluvial deposits at the mouth of the Kagera river Afromontane species in forests on alluvial deposits at the mouth of the Kagera river Guineo‐congolian species in forests on alluvial deposits at the mouth of the Kagera river Lake Victoria swamp forest; Zambezian swamp forest Sudanian riparian forest (Syzygium guineense ssp. guineense ) Zambezian swamp forest Somalia‐Masai riparian forest Guineo‐congolian species in forests on alluvial deposits at the mouth of the Kagera river Afromontane species in forests on alluvial deposits at the mouth of the Kagera river Zanzibar‐Inhambane swamp forest Lake Victoria swamp forest; Zambezian swamp forest f f C f x C x C f C f C f x f f f f f f f x x f f x f f f f f f f f x f f f f x x f f f f f f C C f f f f f f C x f f f x x f f 31 10. Riverine forests (edaphic forest type, fr) 10.1. Description Although White (1983) treated riverine forests separately within the descriptions of regional centres of endemism, we decided not to map floristic variants of riverine forests. Actually, it was in most situations not practical to map riverine forests. Zambezian riparian forest can be further classified in: (i) evergreen or semievergreen riparian forest; and (ii) deciduous riparian forest. Evergreen or semi-evergreen riparian forest of 20 m (or taller) occurs on fringes or perennial streams in areas where annual rainfall exceeds 1000 mm. Riparian forest where most of the tree species are deciduous for at least two months are confined to the banks of major watercourses in areas where annual rainfall is less than 800 mm. The latter riparian forest type has probably always been kept open by movements and browsing of large mammals, which explains the presence of heliophilous (‘sun-loving’) species of Acacia and other genera (White 1983 p. 91). Evergreen riparian forests are among the associated vegetation types that characterize wetter miombo woodland (Wn), whereas deciduous riparian forests are among the associated vegetation types that characterize drier miombo woodland (White 1983 p. 93). Sudanian riparian forest was further classified in: (i) semi-evergreen riparian forest; and (ii) semi-deciduous riparian forest. The former occurs in the southern (wetter) half of the Sudanian region, whereas the latter occurs in the northern (drier) half of the Sudanian region where it is often degraded to riparian woodland (White 1983 p. 105). Somalia-Masai riparian forest occurs only on the banks of larger rivers such as the Galana, Kiboko, Tana, Uaso Nyiro and Voi rivers of Kenya (riparian forests also occur in Tanzania; White 1983 p. 117). Since we think that the riverine occurrence of riverine forests is more characteristic than the species composition of these forests, we refer to section 20.3 for information about characteristic species. 10.2. Species composition (Please check the methodology and information from Volumes 2 - 5 for more details on how the information on species composition for the different manifestations of this potential natural vegetation type was compiled. In composition tables, "x" indicates that the species is expected to be present, "C" indicates that the species was identified as characteristic species and "f" indicates a species that was not listed in the documentation that we consulted although it is known to occur in the specific country). 32 Figure Rusumo 10.1. Riverine along forest Akagera at River (Rwanda). Photograph by E. Fischer (October 1985). Figure 10.2. Riverine forest dominated by Cynometra and Baphia species along the Mpanga River Gorge (Kamwenge, Uganda). Photograph by J. Kalema (January 2009). 33 Acacia asak Acacia elatior Acacia galpinii Acacia gerrardii Acacia kirkii Acacia nigrescens Acacia oerfota Acacia polyacantha Acacia robusta Acacia seyal Acacia sieberiana Acacia tortilis Acacia xanthophloea Acokanthera oppositifolia Afzelia quanzensis Albizia glaberrima Albizia grandibracteata Albizia petersiana Albizia saman Albizia schimperiana Albizia versicolor Albizia zimmermannii Albizia zygia Allophylus abyssinicus Allophylus africanus Allophylus rubifolius Annona senegalensis Anthocleista grandiflora Antiaris toxicaria Antidesma venosum Aphania senegalensis Apodytes dimidiata Baikiaea insignis Balanites aegyptiaca Balanites wilsoniana Berchemia discolor Bersama abyssinica Blighia unijugata Bombax rhodognaphalon Borassus aethiopum Breonadia salicina Bridelia brideliifolia Bridelia micrantha Burttdavya nyasica Cadaba farinosa Caesalpinia volkensii Calodendrum capense Calotropis procera Capparis tomentosa Carissa spinarum Celtis africana Clausena anisata Combretum imberbe Cordia africana Cordia monoica Cordia sinensis Cordyla africana Craibia brownii Crateva adansonii Crotalaria agatiflora Croton macrostachyus Croton megalocarpus Cussonia spicata Delonix elata Diospyros abyssinica Diospyros mespiliformis Diospyros scabra Dobera glabra Dombeya buettneri Dombeya kirkii Dovyalis abyssinica Dovyalis macrocalyx Dracaena steudneri Ehretia cymosa Ekebergia capensis Elaeodendron buchananii Embelia schimperi Ensete ventricosum Entada abyssinica Erythrina excelsa 34 Regional status Coast Zambia Uganda Tanzania C Malawi C Rwanda K enya (woodland subtype) Ethiopia SPECIES Kenya (forest subtype) Table 10. Species composition of Riverine forests (edaphic forest type, fr) x Somalia‐Masai riparian forest Zambezian deciduous riparian forest f C C f C x f f f f x C x C C x C C C C f C C C C C f C C C x C C C f C C x f Lake Victoria swamp forest f C f f x f Zambezian deciduous riparian forest Somalia‐Masai and Zambezian deciduous riparian forest Sudanian riparian forest Zambezian deciduous riparian forest, along larger seasonal streams in Marsabit district Zambezian deciduous riparian forest Somalia‐Masai riparian forest x (exotic species) f Zambezian deciduous riparian forest Somalia‐Masai riparian forest x x f f riparian forest in the greater Serengeti region Afromontane species in forests on alluvial deposits at the mouth of the Kagera river Guineo‐congolian species in forests on alluvial deposits at the mouth of the Kagera river (dominant) f f C C f C C C f C x x C f C C C C C x C C x x x (palm species) Sudanian and Zambezian evergreen or semi‐evergreen riparian forest x x x C f f C Zambezian deciduous riparian forest x f f Somalia‐Masai, Sudanian and Zambezian deciduous riparian forest Somalia‐Masai riparian forest riparian forest in the greater Serengeti region f x C x f f f x f x f f x x f C C C f C C C C C C f C C x x C C C f f C C f f C C f f x f C f x f x x x f f x x x x f x x f f f f x f f f f x x f f x D C x x C C f C f f f f f f f f f f f f f f f f f f f f f f f f f f f f f f f f f f f f f x x x C f f f x x C f f f f f f x f C f C x f x x f x x x x f f f C f f f f f f f f f x f f f f f f f f f f f f f f f f f f f f f f f C C f C f C f x f x f f x x x x f x f x Zambezian deciduous riparian forest f x x x f f f f f f f f f f x x x x x x f x x f f f f f f f f f f f f f x f f f f f x x f f f f f f f f f f f C f f f f f f f f f f f f f f f C f f f C f f f f f f f x f f f C f f f f C f f f f f f f x f f f x C x f f C C C C f f f f f f C C x f f x f f f f f f f f f C C f f f C f C C C f f f f f x f f f f f f x C f f f f f x f x f f f f Ilex mitis Jatropha curcas Justicia schimperiana Khaya anthotheca Kigelia africana Kigelia moosa Landolphia buchananii Lannea schweinfurthii Lawsonia inermis Lecaniodiscus fraxinifolius Leptadenia hastata Maerua decumbens Maesa lanceolata Maesopsis eminii Manilkara mochisia Markhamia lutea Maytenus arbutifolia Maytenus senegalensis Milicia excelsa Mimusops bagshawei Mimusops kummel Mimusops obtusifolia Mimusops zeyheri Monodora myristica Monopetalanthus richardsiae Moringa stenopetala Mussaenda arcuata Myrianthus holstii Newtonia buchananii Newtonia hildebrandtii Oncoba spinosa Oreobambos buchwaldii Oxystigma msoo Parinari excelsa Parkia filicoidea Parkinsonia aculeata Pavetta oliveriana Phoenix dactylifera Phoenix reclinata Phytolacca dodecandra Piliostigma thonningii Pittosporum viridiflorum Polyscias fulva Populus ilicifolia Premna schimperi Prunus africana Somalia‐Masai riparian forest (near coast and endemic to coastal forests) Somalia‐Masai riparian forest Zambezian deciduous riparian forest Somalia‐Masai, Sudanian and Zambezian deciduous riparian forest Somalia‐Masai riparian forest (including greater Serengeti region) (palm species) (palm species) (palm species) Afromontane species in forests on alluvial deposits at the mouth of the Kagera river; Zambezian swamp forest x f x x C x x x x x f x f x f f f f Somalia‐Masai (including greater Serengeti region) and Zambezian deciduous riparian forest C f f f Malawi Rwanda x x x f x x f x x x f f f x x f x f x f f f C x x x x f x f f f f C x f f C C x x x f f C C x x C C C x C x f f x C C C f f f f C f C C C f C C f x Somalia‐Masai and Zambezian evergreen or semi‐evergreen riparian forest Somalia‐Masai and Zambezian deciduous riparian forest C x Guineo‐congolian species in forests on alluvial deposits at the mouth of the Kagera river Zambezian deciduous riparian forest C x f f f f C x C f x f x f x x x f x f f C x f f f x f x f Zambezian deciduous riparian forest C Zambezian evergreen or semi‐evergreen riparian forest f x Zambezian evergreen or semi‐evergreen riparian forest; near streams in Afromontane dry transitional forest Somalia‐Masai and Zambezian deciduous riparian forest x (bamboo species indigenous to Africa) Somalia‐Masai and Zambezian evergreen or semi‐evergreen riparian forest (Lake Victoria swamp forest) x Lake Victoria swamp forest; Zanzibar‐Inhambane swamp forest; palm species C f f f Somalia‐Masai riparian forest x f f f C C C C C C x C C x C C f C C C C f f f f C x x x x x f C x x f x x f x x f x f f x f Coast Zambezian deciduous riparian forest f x f f C C C f f C f f f C C C C C C C C C f C C C C f C f C C f Zambia x f Uganda Zambezian evergreen or semi‐evergreen riparian forest Tanzania Erythrophleum suaveolens Erythroxylum fischeri Euclea divinorum Euclea natalensis Euclea racemosa Eugenia capensis Faidherbia albida Faurea saligna Fernandoa magnifica Ficus exasperata Ficus ingens Ficus natalensis Ficus ovata Ficus sur Ficus sycomorus Ficus thonningii Ficus vallis‐choudae Ficus vasta Filicium decipiens Flacourtia indica Flueggea virosa Garcinia livingstonei Gardenia ternifolia Gardenia volkensii Grewia villosa Harrisonia abyssinica Hymenaea verrucosa Hypericum quartinianum Hyphaene compressa Hyphaene coriacea Hyphaene petersiana K enya (woodland subtype) Ethiopia Regional status Kenya (forest subtype) SPECIES f f f f f f f f x f f f f f C f f f f f f f f f f f f f f f f f f f C C C f x f x f f f C C f f f f f f f f f f f x f f f f C f f f f f f f f f f f x f C f f x f x C x f f C f f f C C C f C f f f C C f f f f f f C f f x f f f f C f f f f f f f f x f f f f f f f f f f f f f f f f f f f f f f f f f f f x f f f C C f C C f f C x f f C f C C f x C f f f f f C f f f f f f f f f f x f f C x C C f f C f f f f f f f f f f f f f f f f x f f f f f C C C f f f 35 Strychnos mitis Strychnos potatorum Strychnos spinosa Suregada procera Synsepalum brevipes Syzygium cordatum Syzygium guineense Syzygium owariense Tamarindus indica Tamarix aphylla Tamarix nilotica Tarenna graveolens Terminalia brownii Terminalia prunioides Terminalia sambesiaca Tetradenia riparia Trema orientalis Trichilia dregeana Trichilia emetica Uvaria scheffleri Vangueria apiculata Vangueria infausta Vangueria madagascariensis Vepris nobilis Vernonia amygdalina Vernonia myriantha Vitex doniana Warburgia ugandensis Woodfordia uniflora Xanthocercis zambesiaca Xylopia parviflora Zanha golungensis Zanthoxylum gilletii Ziziphus abyssinica Ziziphus mauritiana Ziziphus mucronata Ziziphus pubescens Ziziphus spina‐christi 36 C x x f x f Afromontane species in forests on alluvial deposits at the mouth of the Kagera river Zambezian deciduous riparian forest x f Lake Victoria swamp forest; Zambezian swamp forest Sudanian riparian forest (Syzygium guineense ssp. guineense ) Zambezian swamp forest Somalia‐Masai and Sudanian riparian forest C C x C f f f f x x x f f x C C f x x f x x x f f f f f C C C C x x Somalia‐Masai and Zambezian deciduous riparian forest C x Sudanian riparian forest Afromontane species in forests on alluvial deposits at the mouth of the Kagera river Zambezian deciduous riparian forest Malawi f f C x f f f f f f f f f f f f f f f C x f x f f C f f f f f f x x f f f f x f f f x f C x f C C C C C x C C C C x f C C C C C C C C C f f Somalia‐Masai riparian forest C f x f f f f f f x C Coast x x x f x x x f x f Zambia f C C C C C C C C C C C C C C C C C C C C C C C C C Uganda Lake Victoria swamp forest (palm species) x x x f f f Tanzania C C Rwanda Lake Victoria swamp forest; Guineo‐congolian species in forests on alluvial deposits at the mouth of the Kagera river K enya (woodland subtype) Ethiopia Pseudospondias microcarpa Psychotria mahonii Pterocarpus tinctorius Raphia farinifera Rauvolfia caffra Rhoicissus revoilii Rhus longipes Ritchiea albersii Rothmannia urcelliformis Saba comorensis Salvadora persica Sclerocarya birrea Scutia myrtina Senna didymobotrya Senna septemtrionalis Sesbania macrantha Sesbania sesban Shirakiopsis elliptica Sideroxylon inerme Smilax anceps Solanecio mannii Solanum aculeastrum Sorindeia madagascariensis Spathodea campanulata Spirostachys venenifera Steganotaenia araliacea Sterculia appendiculata Strychnos henningsii Regional status Kenya (forest subtype) SPECIES C f x x f x x C C x f f f f f x f f C f f f C f f f f x x x f C f f x x f f f x x f x f f x f f f f f f f f f f f f f f f f f f x x f f f f f f f f C f f f f f f f f f f f f f f f f f f f f f x f f f f x f f f x x f f x f C f C f f f f f f f f f f f f f C f f x C C f x f x f f C f f f f f f f f f f f f f f f f f f f f f f f f f f f f f f f f f x f x f f C x f f x x f C f f f f f x f f f f x x f f C f C f f f C f f C f f f f f C f f f f f f 11. Swamp forest (edaphic forest type, fs) 11.1. Description In analogy with riverine forests (fr), we decided not to map floristic variants of riverine forests although White (1983) treated riverine forests separately within the descriptions of regional centres of endemism. Actually, it was in most situations not practical to map swamp forests. In the wetter parts of the Zambezian region (with rainfall above 1000 mm), permanent swamp forest occurs around springs at the sources of tributary streams. Swamp forests also occurs along watercourses (i.e. also as subtype of riverine forest [fr]) where water movement is locally sluggish. In the latter situation, swamp forests merge into other types of riparian forest in which the water table is at some distance below the surface for at least part of the year (White 1983 p. 91). Although White (1983) lists a heading within the description of the Sudanian region as “Sudanian swamp forest and riparian forest”, he does not give a specific description of Sudanian swamp forest (White 1983 pp. 103 - 104). Swamp forests dominated by species that are widespread in tropical Africa occur extensively on the shores of Lake Victoria and elsewhere in the Lake Victoria region. On alluvial deposits of the Kagera river (on the western shore of Lake Victoria), a unique swamp forest occurs that is composed almost in equal proportions of lowland (especially Guineo-Congolian) and Afromontane species and that is dominated by Baikiaea insignis (a Guineo-Congolian species) and by Podocarpus usambarensis var. dawei (an Afromontane species; White 1983 p. 181). Fresh-water swamp forest is of restricted occurrence in the Zanzibar-Inhambane region. Barringtonia racemosa, a species associated with mangroves (M), often occurs in swamp forests immediately behind the mangrove zone and extends upstream for considerable distances (White 1983 p. 188). 11.2. Species composition (Please check the methodology and information from Volumes 2 - 5 for more details on how the information on species composition for the different manifestations of this potential natural vegetation type was compiled. In composition tables, "x" indicates that the species is expected to be present, "C" indicates that the species was identified as characteristic species and "f" indicates a species that was not listed in the documentation that we consulted although it is known to occur in the specific country). 37 Baikiaea insignis Barringtonia racemosa Beilschmiedia ugandensis Blighia unijugata Bridelia micrantha Canarium schweinfurthii Celtis africana Celtis gomphophylla Clausena anisata Combretum imberbe Cordia africana Cordyla africana Craterispermum laurinum Croton megalocarpus Diospyros mespiliformis Dombeya rotundifolia Dracaena camerooniana Ekebergia capensis Elaeis guineensis Erythrina abyssinica Erythrina excelsa Erythrophleum suaveolens Erythroxylum fischeri Euclea divinorum Faidherbia albida Ficalhoa laurifolia Ficus natalensis Ficus sur Ficus sycomorus Ficus trichopoda Ficus vallis‐choudae Flueggea virosa Funtumia africana Garcinia smeathmannii Gardenia imperialis Hallea stipulosa Hibiscus tiliaceus Ilex mitis Khaya anthotheca Kigelia africana Klainedoxa gabonensis Lannea schweinfurthii Lecaniodiscus fraxinifolius Macaranga monandra Macaranga schweinfurthii Macaranga spinosa Maesa lanceolata Maesopsis eminii Musanga cecropioides Newtonia buchananii Parinari excelsa 38 Afromontane species in forests on alluvial deposits at the mouth of the Kagera river Zambezian swamp forest Guineo‐congolian species in forests on alluvial deposits at the mouth of the Kagera river (dominant) Zanzibar‐Inhambane swamp forest, also mangrove associated species Guineo‐congolian species in forests on alluvial deposits at the mouth of the Kagera river f C f f f f f f f f f f f f f f f f f Zambezian swamp forest riparian forest in the greater Serengeti region Zanzibar‐Inhambane swamp forest (palm species) Zambezian deciduous riparian forest Somalia‐Masai, Sudanian and Zambezian deciduous riparian forest Lake Victoria swamp forest; Zambezian swamp forest f f Zambezian swamp forest Zambezian swamp forest Lake Victoria swamp forest; Zambezian swamp forest Zanzibar‐Inhambane swamp forest, also mangrove associated species Afromontane species in forests on alluvial deposits at the mouth of the Kagera river; Zambezian swamp forest Somalia‐Masai and Zambezian evergreen or semi‐evergreen riparian forest Somalia‐Masai and Zambezian deciduous riparian forest Guineo‐congolian species in forests on alluvial deposits at the mouth of the Kagera river f f C C x f f f f f f x f f x f f f f f f f D f x x x f C f C f x f f C f f f C x f f x f f C f x f f f f x f f f x f f x f f f f f f f f f C f f f f f f f f f f f f f x f x f x x f x f f f x x x f f x x f f f f f f f f f f f f f f x f f f f f C f x f f C C f f f f f f f C C f C C x f f f f f f f x f f f f f x C f f f f x C C f x f Somalia‐Masai (including greater Serengeti region) and Zambezian deciduous riparian forest Lake Victoria swamp forest Lake Victoria swamp forest Lake Victoria swamp forest x f x C f f x f f x f f f x x f f f f f C f C f C f f f f f f f f f f f x f f f f f x x f f f x x C x f f f f f f f f f C f f f C f f x f f f f f f f f f f f C f x x x f f f f f x f x f f x x f f f f f f f f f x f f f C C f Guineo‐congolian species in forests on alluvial deposits at the mouth of the Kagera river Lake Victoria swamp forest Zambezian evergreen or semi‐evergreen riparian forest; near streams in Afromontane dry transitional forest f C f f f f f x x f x f C f f f f f f f f f f f f f f f f f C f C Lake Victoria swamp forest Zambezian evergreen or semi‐evergreen riparian forest C C f f f f f f f f f C f f f f f f f f f f f Zambezian deciduous riparian forest Zambezian deciduous riparian forest Zambezian swamp forest Afromontane species in forests on alluvial deposits at the mouth of the Kagera river Somalia‐Masai, Sudanian and Zambezian deciduous riparian forest f f x f Coast Kenya f f C Zambia Apodytes dimidiata Aporrhiza nitida Lake Victoria swamp forest f Uganda (fsrU subtype) Lake Victoria swamp forest Zanzibari‐Inhambane swamp forest (fern species) Somalia‐Masai riparian forest Uganda (fsbU subtype) Acacia kirkii Acrostichum aureum Albizia glaberrima Alchornea hirtella Anthocleista grandiflora Anthocleista schweinfurthii Antidesma venosum Rwanda Regional status Tanzania SPECIES Malawi Ethiopia Table 11. Species composition of Swamp forest (edaphic forest type, fs) f x f f C f f f f f f Strombosia scheffleri Strychnos mitis Symphonia globulifera Syzygium cordatum Syzygium guineense Syzygium owariense Terminalia sambesiaca Tetrapleura tetraptera Trichocladus ellipticus Typhonodorum lindleyanum Uapaca guineensis Vangueria madagascariensis Vepris nobilis Vitex doniana Voacanga thouarsii Warburgia ugandensis Xylopia aethiopica Xylopia rubescens Ziziphus pubescens Zambia Coast Pycnanthus angolensis Raphia farinifera Rauvolfia caffra Ritchiea albersii Rothmannia urcelliformis Schrebera arborea Scutia myrtina Shirakiopsis elliptica Sorindeia madagascariensis Spondianthus preussii Sterculia tragacantha Uganda (fsrU subtype) Pseudospondias microcarpa Psychotria mahonii Psychotria peduncularis Pterocarpus tinctorius Uganda (fsbU subtype) Podocarpus usambarensis Rwanda Podocarpus latifolius Tanzania Podocarpus falcatus x x f f f x f x f f f C x x f f f f f f f f x f D f f D f f f f C x x f f f f f f f f f x x x x x x x x f f D f x C f f C f Kenya Phoenix reclinata f f Malawi Parkia filicoidea Peddiea fischeri f C f f C f f Ethiopia SPECIES Regional status Lake Victoria swamp forest (also Somalia‐Masai and Zambezian evergreen or semi‐evergreen riparian forest) Lake Victoria swamp forest; Zanzibar‐Inhambane swamp forest; palm species Afromontane species in forests on alluvial deposits at the mouth of the Kagera river Afromontane species in forests on alluvial deposits at the mouth of the Kagera river Afromontane species in forests on alluvial deposits at the mouth of the Kagera river (dominant [Podocarpus usambarensis var. dawei ]) Lake Victoria swamp forest; Guineo‐congolian species in forests on alluvial deposits at the mouth of the Kagera river f C C f Zambezian swamp forest Guineo‐congolian species in forests on alluvial deposits at the mouth of the Kagera river Lake Victoria swamp forest (palm species) f f f f f f f C f f f x f f f C f f f f f x C f C C Sudanian riparian forest Lake Victoria swamp forest; Zanzibar‐Inhambane swamp forest Afromontane species in forests on alluvial deposits at the mouth of the Kagera river Zambezian swamp forest Zambezian swamp forest f f f f f C f f D f D f f f f f f f C f f C f f f f f f f f f C f f f C C f f f x f f f f x f f f x f f f f f f C x f x f f x f f f C x f f f f x f f f f f f Lake Victoria swamp forest Afromontane species in forests on alluvial deposits at the mouth of the Kagera river Afromontane species in forests on alluvial deposits at the mouth of the Kagera river Guineo‐congolian species in forests on alluvial deposits at the mouth of the Kagera river Lake Victoria swamp forest; Zambezian swamp forest Sudanian riparian forest (Syzygium guineense ssp. guineense ) Zambezian swamp forest Somalia‐Masai riparian forest Guineo‐congolian species in forests on alluvial deposits at the mouth of the Kagera river Afromontane species in forests on alluvial deposits at the mouth of the Kagera river Zanzibar‐Inhambane swamp forest Lake Victoria swamp forest; Zambezian swamp forest f f C f x C x C f C f C f x f f f f f f f x x f f x f f f f f f f f x f f f f x x f f f f f f C C f f f f f f C x f f f x x f f 39 12. Biotic Acacia wooded grassland (We) 12.1. Description Where domestic animals (5) are numerous, East African evergreen bushland (Be, see Volume 4) has been severely degraded and invaded by Acacia species. It is therefore typical to find Acacia drepanolobium (a species that also occurs in Somalia-Masai edaphic grassland [we]), Acacia hockii, Acacia kirkii and Acacia seyal (a species that also occurs in Somalia-Masai edaphic grassland [we])) occurring together with evergreen species such as Carissa edulis, Dodonaea viscosa, Euclea divinorum, Euclea racemosa and Tarchonanthus camphoratus (White 1983 p. 115). In the greater Serengeti region, Acacia gerrardii dominates secondary wooded grassland that replaces evergreen bushland, but it also occupies large areas of poorly drained clay soils (White 1983 p. 128). Evergreen bushland (Be) communities of the Lake Victoria region have been extensively destroyed and replaced by a lightly wooded Acacia grassland dominated by Acacia hockii, Acacia gerrardii, Acacia kirkii, Acacia senegal (the latter also a characteristic species of deciduous bushland [Bd](6)) and Euphorbia candelabrum (also an emergent of evergreen bushland [Be]). White (1983 p. 182) cites references from Lebrun (1947, 1955) and Liben (1961) that suggest the pathways how evergreen thicket can regenerate within biotic Acacia wooded grassland. In one pathway, liana species germinate in the shade of the Acacias. These lianas eventually smother the crowns of the Acacias, which then creates suitable conditions for the establishment of shrubs and bushes. The shade from these shrubs and bushes finally completely suppresses the heliophilous (‘sun-loving’) Acacias that are no longer able to regenerate. In the alternative pathway, the shade from Euphorbia candelabrum causes a diminution in the vigour of the grass layer which then allows the invasion of woody plants (White 1983 p. 182). We suggest that biotic Acacia wooded grassland is an alternative steady state of potential natural vegetation (corresponding to disturbance by animals) to the steady state of evergreen bushland (Be, corresponding to limited disturbance by animals). The degree of grazing pressure therefore determines the proportions of biotic Acacia wooded grassland compared to evergreen bushland (Be). 5: The same situation arises with wild animals 6: The variety of Acacia senegal var. senegal is a typical variety of biotic Acacia wooded grassland, whereas the variety of Acacia senegal var. kerensis is a typical variety of deciduous bushland (Bd; F. Gachathi, pers. comm.). 40 Figure 12 .1. Vegetation that was originally classified as “Acacia wooded grassland of the Rift Valley” (ACB-RV) was reclassified by VECEA as biotic Acacia wooded grassland. Early dry season aspect with discontinuous ground cover. Awash National Park near the Fantale volcano (Ethiopia). Photograph by I. Friis and Sebsebe Demissew (October 2006). Reproduced from Biologiske Skrifter of the Royal Danish Academy of Sciences and letters, Vol. 58, Fig 16A. 2010. Figure 12.2. Acacia senegal var. senegal in Kajiado District (Kenya). The variety of Acacia senegal var. senegal is a typical variety of biotic Acacia wooded grassland, whereas the variety of Acacia senegal var. kerensis is a typical variety of deciduous bushland (Bd). Photograph by F. Gachathi (2008). 41 Figure 12.3. Vegetation that was originally classified as “Acacia – Cymbopogon / Themeda dry Acacia savanna” (original mapping unit P1; Cymbopogon and Themeda are grass genera) was reclassified as biotic Acacia wooded grassland by VECEA. The picture shows an area close to drier Combretum wooded grassland (Wcd) near Maddu (Uganda). Photograph by J. Kalema (November 2010). Figure 12.4. Biotic Acacia wooded grassland in Akagera National Park (Rwanda). Photograph by C.K. Ruffo (October 2009). Figure 12.5. Acacia gerrardii – Acacia seyal wooded grassland with Themeda grass understorey. Height of vegetation in meter. Pratt et al. (1966, Fig 3b). Image obtained from URL: http:// www.jstor.org/stable/2401259 42 12.2. Species composition (Please check the methodology and information from Volumes 2 - 5 for more details on how the information on species composition for the different manifestations of this potential natural vegetation type was compiled. In composition tables, "x" indicates that the species is expected to be present, "C" indicates that the species was identified as characteristic species and "f" indicates a species that was not listed in the documentation that we consulted although it is known to occur in the specific country). 43 Elaeodendron buchananii Euclea divinorum Euclea racemosa Euphorbia candelabrum Grewia bicolor Grewia similis Pterolobium stellatum Rhus natalensis Schrebera alata Scutia myrtina Tarenna graveolens Acacia drepanolobium Acacia seyal Grewia tembensis Acacia brevispica Acacia mellifera Acacia polyacantha Acacia sieberiana Acacia tortilis Acacia xanthophloea Albizia adianthifolia Albizia amara Allophylus rubifolius Bersama abyssinica Boscia angustifolia Boscia salicifolia Combretum molle Commiphora habessinica Cordia africana Cussonia arborea Dichrostachys cinerea Dombeya buettneri Dombeya rotundifolia Entada abyssinica Erythrina abyssinica Erythrina burttii Faidherbia albida Ficus glumosa Gardenia ternifolia Lannea fulva Lannea humilis Lannea schimperi Lannea schweinfurthii Maytenus senegalensis Ozoroa insignis Pappea capensis Parinari curatellifolia Senna didymobotrya Terminalia brownii Vangueria infausta Ximenia americana Ziziphus abyssinica Ziziphus mucronata 44 not characteristic not characteristic not characteristic WesU (Uganda subtype) Cussonia holstii Dodonaea viscosa Tanzania indicator species indicator species indicator species indicator species indicator species for evergreen and semi‐evergreen bushland and thicket indicator species for evergreen and semi‐evergreen bushland and thicket indicator species for evergreen and semi‐evergreen bushland and thicket indicator species for evergreen and semi‐evergreen bushland and thicket (transition to forest) indicator species for evergreen and semi‐evergreen bushland and thicket indicator species for evergreen and semi‐evergreen bushland and thicket (transition to forest) indicator species for evergreen and semi‐evergreen bushland and thicket indicator species for evergreen and semi‐evergreen bushland and thicket indicator species indicator species for evergreen and semi‐evergreen bushland and thicket indicator species for evergreen and semi‐evergreen bushland and thicket indicator species for evergreen and semi‐evergreen bushland and thicket indicator species for evergreen and semi‐evergreen bushland and thicket indicator species for evergreen and semi‐evergreen bushland and thicket (transition to forest) indicator species for evergreen and semi‐evergreen bushland and thicket indicator species for evergreen and semi‐evergreen bushland and thicket characteristic species characteristic species characteristic species for evergreen bushland and deciduous bushland WecU (Uganda subtype) Acacia gerrardii Acacia hockii Acacia kirkii Acacia senegal Acokanthera schimperi Capparis tomentosa Carissa spinarum Kenya Regional status Rwanda SPECIES Ethiopia Table 12. Species composition for biotic Acacia wooded grassland (We) f f C f f f C C C x x x x C x C C f f f f f f f f f f C x f x f f f C x f f f f f f f f x x f f f f f f f f f f C f f f f f x f x x x x x x f x C f f f f f f f f f f f x f f f f f f f f f f f f f f f f C f f f f f C f x x C C x C C C x C C f C x x x x x x x x x x f x f f f f f f f f f f f f f x x f f f f f f f f f f f f f f f f f f f f x f f f f f f x f f f f f f f f f f f f f f f x x f f f f f f f x f f f f f f f f f f f f f f f f f f f f x f f f f x f f f f f f f f f f f f f f f f f x x f f f f f f f f f x f f f f f f f f f f x f f f f C f f not characteristic f f f x f f f x f f f x f x x x x x f f x x x x x x x x x x x x f x f C f C C C C x x x x x x x f x x C x x x x x x x x x x C x x x f x 13. Palm wooded grassland physiognomically easily recognized type, P 13.1. Description White (1983) did not describe palm wooded grasslands as a separate vegetation type in his main treatment of floristic regions. However, he describes Hyphaene coriacea palm stands that occur on sites with permanent ground water at the edge of the Chalbi desert and at the base of Mt. Kulal (White 1983 p. 123). Borassus aethiopum and Hyphaene petersiana (synonym: Hyphaene ventricosa) are among the characteristic species of the riparian woodland subtype of Undifferentiated woodland and wooded grassland (Wn, White 1983 p. 95). Borassus aethiopum is listed to occur in seasonally inundated flood plains in the Sudanian floristic region (White 1983 p. 107). Borassus aethiopum and Hyphaene thebaica occur on transition zones between swamp grassland and better drained areas with Acacia seyal in the flood region of the Nile (White 1983 p. 108). Hyphaene compressa occurs in Zanzibar-Inhambane edaphic wooded grassland (White 1983 p. 189). Phoenix reclinata and Raphia farifera are palm species that are listed among the more important species of swamp forests that are widespread in the Lake Victoria region and elsewhere (White 1983 p. 181). Phoenix reclinata occurs in swamp forests in the Zanzibar-Inhambane region (White 1983 p. 188). Lind and Morrison (1974 p. 94) mention that palm wooded grassland is limited in area, but so noticeable that it needed to be included in descriptions of East African vegetation types. The main species is Borassus aethiopum. In Uganda, it is found on sands and sandy loams with mobile ground water. In Kenya, it is scattered through the coastal belt and is noticeable on the Shimba Hills. In Tanzania, extensive stands occur in the flood plains of the Igombe and Ugala rivers and other riverine communities where it is sometimes accompanied by Hyphaene doum palm species. Hyphaene coriacea is the dominant palm species on the Ruaha - Usangu plain complex and in the Warmi and Mkata flood plains. Borassus stands are more common than Hyphaene in parts of the coastal plain, but small trees (up to 3 m) of Hyphaene form extensive stands in grassland on poorly drained sands. From the descriptions above it is clear that the palm stands that were described often occur in areas with drainage impediments or riverine locations. It would therefore be perfectly acceptable to classify and map these vegetation types as “edaphic wooded grassland” (wd) or “riverine wooded grassland” (wr), which we have done in several situations. We think that discrimination between these types is more a question of the scale of mapping since palm trees can easily be identified in the field. 45 Figure 13.1. Borassus - Hyperthelia dissoluta [a grass species, synonym: Hyparrhenia dissoluta,] palm wooded grassland (original mapping unit M2) from Uganda. Photograph by J. Kalema. Figure 13.2. Stand of Phoenix reclinata in waterlogged area within Afromontane rain forest (Fa). Photograph by I. Friis and Sebsebe Demissew. Reproduced from Biologiske Skrifter of the Royal Danish Academy of Sciences and letters, Vol. 58, Fig 25G. 2010. Figure 13.3. Hyphaene petersiana wooded grassland next to the Shire River marsh and lagoons (Liwonde National Park, Malawi). An alternative classification method for this vegetation type would have been as “edaphic wooded grassland on drainage-impeded or seasonally flooded soils". Photograph by C. Dudley. 46 13.2. Species composition (Please check the methodology and information from Volumes 2 - 5 for more details on how the information on species composition for the different manifestations of this potential natural vegetation type was compiled. In composition tables, "x" indicates that the species is expected to be present, "C" indicates that the species was identified as characteristic species and "f" indicates a species that was not listed in the documentation that we consulted although it is known to occur in the specific country). Hyphaene coriacea Hyphaene petersiana Hyphaene thebaica Phoenix reclinata Raphia farinifera Acacia erioloba Acacia nigrescens Acacia polyacantha Acacia sieberiana Acacia xanthophloea Adansonia digitata Albizia versicolor Burkea africana Combretum collinum Diospyros mespiliformis Faidherbia albida Kigelia africana Lannea schweinfurthii Lonchocarpus capassa Piliostigma thonningii Sterculia africana Terminalia sericea Trichilia emetica P2U (Uganda subtype) Zambia Coast f P1U (Uganda subtype) C C C C Rwanda C Tanzania Kenya Borassus aethiopum Cocos nucifera Elaeis guineensis Hyphaene compressa Malawi SPECIES Ethiopia Table 13. Species composition for Palm wooded grassland physiognomically easily recognized type, P f f f f D D f f f C C C C Regional Status Palm species (occurs in the riparian woodland subtype of north Zambezian undifferentiated woodland, in Sudanian edaphic grassland on Pleistocene clays, and in Zanzibar-Inhambane secondary grassland and wooded grassland) Palm species (occurs in Zanzibar-Inhambane edaphic grassland and secondary grassland) Palm species Palm species (occurs in Zanzibar-Inhambane edaphic grassland and secondary grassland) Palm species (small stands with permanent ground water at the edge of the Chalbi desert and at the base of Mt. Kulal) Palm species (occurs in the riparian woodland subtype of north Zambezian undiffertiated woodland) Palm species (occurs in Sudanian undifferentiated woodland and in Sudanian edaphic grassland on Pleistocene clays) Palm species (small communities in areas with frequent landslides on Mt. Kulal, Lake Victoria swamp forest, Zanzibar-Inhambane swamp forest Palm species (occurs in Lake Victoria swamp forest) C f C f f D C C C C C C f f C f C C C C f f C C C C C C C f C C f f f f f f x x x x f f x f f f f f x f f x f x x f f f f C f f f C C f f C f f f f f f f f C f 47 14. Evergreen and semi-evergreen bushland and thicket (synonym: evergreen bushland, Be) 14.1. Description Within volumes 2 to 5, we use the synonym of “evergreen bushland (Be)” as a synonym of “evergreen and semi-evergreen bushland and thicket (Be)”. White (1983) describes evergreen and semi-evergreen bushland and thickets within the descriptions of two floristic regions: (i) the Somalia-Masai regional centre of endemism (‘East African evergreen and semi-evergreen bushland and thicket’); and (ii) the Lake Victoria regional mosaic (‘evergreen and semi-evergreen bushland and thicket and derived communities’). Evergreen and semi-evergreen bushland and thicket occurs on the drier slopes of mountains and upland areas in East Africa which rise from the lowlands from the Somalia-Masai region all the way from central Tanzania to Eritrea (and beyond). It often forms an ecotone between Afromontane forest (especially Afromontane single-dominant Juniperus procera forest [Fbj]) and deciduous bushland (Bd) - this pattern of occurrence can be clearly observed in northern Kenya such as at on the lower slopes of Mt. Marsabit (2º 16’ N, 37º 57’ E). The mean annual rainfall is mostly between 500 and 850 mm and is irregularly distributed throughout the year but with two main peaks (White 1983 pp. 48 and 115). Evergreen bushland varies greatly in composition and richness, but certain species that are nearly always present include Acokanthera schimperi, Carissa spinarum, Dodonaea viscosa, Euclea divinorum, Euphorbia candelabrum, Olea europaea subsp. cuspidata (synonym: Olea africana), Tarchonanthus camphoratus (especially in disturbed areas), Vepris simplicifolia (synonym: Teclea simplicifolia) together with other species of Acokanthera, Aloe, Euclea, Euphorbia, Sanseviera and Vepris. Succulents such as Dracaena ellenbeckiana and Euphorbia candelabrum that are present in evergreen bushland are absent from Afromontane single-dominant Juniperus procera forest (Fbj, White 1983 p. 115). Evergreen bushland (in mosaic with Lake Victoria Euphorbia dawei scrub forest [fe, see Volume 2] that is edaphically restricted to rocky slopes) probably represents the climax vegetation of large parts of the Lake Victoria region. This evergreen bushland variant is floristically similar but also floristically poorer than the vegetation type with the same name that occurs in the Somalia-Masai region. The principal bushy species include Allophylus africanus, Azima tetracantha, Carissa spinarum (also listed as characteristic in East Africa), Capparis fascicularis (listed as a characteristic climber in East Africa), Capparis tomentosa, Erythrococca bongensis, Grewia bicolor, Maerua triphylla, Olea europaea subsp. cuspidata (synonym: Olea africana, also listed as characteristic in East Africa), Psydrax schim48 periana, Rhus natalensis (also listed as characteristic in East Africa), Tarenna graveolens and Turraea nilotica. Annual rainfall is higher in places where evergreen bushland occurs in the Lake Victoria region (850 mm to 1000 mm) than those places where it occurs in the Somalia-Masai region (500 to 850 mm; White 1983 pp. 48 and 182). Where evergreen bushland is degraded (as a result from grazing), various Acacia species invade and biotic Acacia wooded grassland (We) becomes established. This vegetation type forms an alternative steady state of potential natural vegetation to evergreen bushland (i.e. it is possible for both types of potential natural vegetation to become established in the areas where they are mapped separately). The grasslands of the Loita and other plains that occur in Narok district (including parts of the Masai-Mara reserve) are similar in grass species composition as the edaphic grasslands on volcanic soils of the Serengeti plains (gv, see Volume 5). However, these grasslands in Narok district are secondary to evergreen bushland as a result from fire and browsing (White 1983 p. 127). Areas capable of supporting evergreen bushland in Nairobi National Park have been converted to grassland as a result from browsing, grazing and fire (White 1983 p. 116). White (1983) describes relatively undisturbed evergreen bushland (locally impenetrable) that occurred near Nairobi between 1875 and 2080 m. Most of the species that White (1983) listed as characteristic were indicator species (see also section 4.3). Only two species were also listed as characteristic species for deciduous bushland (Bd): Grewia tembensis (listed as a smaller bush and shrub for deciduous bushland and thicket, and as a large bush in East African evergreen bushland) and Sarcostemma viminale (a succulent climber). The indicator species can be further categorized in: (i) characteristic species of the main canopy; (ii) other large bushes; (iii) scattered emergents; (iv) shrubs; (v) climbers; and (vi) scattered stunted individuals that indicate the transition to Afromontane single-dominant Juniperus procera forest (Fbj). • Characteristic species of the main canopy (3 to 7 m) include Acokanthera schimperi, Euclea divinorum, Gnidia subcordata, Olea europaea subsp. cuspidata (synonym: Olea africana], also listed as characteristic species for the Lake Victoria region), Tarchonanthus camphoratus (especially in disturbed areas) and Vepris simplicifolia. (White (1983) did not list Carissa spinarum, but this could be an omission). • Other large bushes include Canthium keniense, Croton dichogamus, Dodonaea viscosa, Dombeya burgessiae, Grewia similis, Maytenus heterophylla and Rhus natalensis (also listed as characteristic species for the Lake Victoria region). • Euphorbia candelabrum (a cactoid stem-succulent) occurs throughout as a scattered emergent up to 9 m tall. This species was also listed as a characteristic species for the Lake Victoria region. 49 • Shrubs include Aspilia mossambicensis, Psiadia punctulata, Tinnea aethiopica and Turraea mombassana. • Climbers include Capparis fascicularis (also listed as characteristic species for the Lake Victoria region), Pterolobium stellatum and Scutia myrtina. • Scattered stunted individuals that indicate the transition to Afromontane single-dominant Juniperus procera forest (Fbj) appear at higher altitudes and include Calodendrum capense, Cussonia holstii, Drypetes gerrardii, Elaeodendron buchananii, Juniperus procera (evergreen bushland could be the original habitat of this species [White 1983 p. 165]) and Schrebera alata. 50 Figure 14.1. Evergreen thicket in Queen Elizabeth National Park (Uganda). Emergent Euphorbia candelabrum covered by climbers can be seen in various places. Photograph by M. Namaganda (June 2008). Figure 14.2. Evergreen and semievergreen bushland next to a remnant of Afromontane single-dominant Juniperus procera forest (Fbj). Near Arero (Ethiopia). Approximate altitude 1800m. Photograph by I. Friis and Sebsebe Demissew (September 2002). Reproduced from Biologiske Skrifter of the Royal Danish Academy of Sciences and letters, Vol. 58, Fig 23A. 2010. Figure 14.3. Stands of Dracaena ombet subsp. ombet in Acaciadominated bushland below remnants of Afromontane single-dominant Juniperus procera forest (Fbj). Between Wukro and Berahile (Ethiopia). Approximate altitude 1700 m. Photograph by I. Friis and Sebsebe Demissew (October 2009). Reproduced from Biologiske Skrifter of the Royal Danish Academy of Sciences and letters, Vol. 58, Fig 23B. 2010. 51 Figure 14.4. Regrowth of Tarchonanthus camphoratus in evergreen bushland in a transition zone between Acacia-Commiphora deciduous bushland and Afromontane singledominant Juniperus procera forest (Fbj). Between Wukro and Berahile (Ethiopia). Approximate altitude 2000 m. (October 2009). Photograph by I. Friis and Sebsebe Demissew. Reproduced from Biologiske Skrifter of the Royal Danish Academy of Sciences and letters, Vol. 58, Fig 23D. 2010. Figure 14.5. Evergreen bushland and thicket in Biharagu (Rwanda). Photograph taken by E. Munyaneza (October 2009). Figure 14.6. Evergreen bushland was the original vegetation type of most of the Akagera National Park (Rwanda). Photograph by V. Minani (March 2007). 52 Figure 14.7. As a result from grazing, the original evergreen bushland of Akagera national park (Rwanda) has changed to the alternative steady state of biotic Acacia wooded grassland (We). Climbers growing on Euphorbia candelabrum (right) can initiate the vegetation succession to evergreen bushland (see also Lebrun [1947] and White [1983 p. 183]; Photograph by D. König (September 1987). Figure 14.8. Evergreen bushland in the Maasai Mara (original mapping unit 24). The photograph shows Diospyros abyssinica together with typical evergreen bushland species of Euclea divinorum, Olea europaea ssp. cuspidata (synonym: Olea africana). Person: C.G. Trapnell. Photography by E.C. Trump. 53 14.2. Species composition (Please check the methodology and information from Volumes 2 - 5 for more details on how the information on species composition for the different manifestations of this potential natural vegetation type was compiled. In composition tables, "x" indicates that the species is expected to be present, "C" indicates that the species was identified as characteristic species and "f" indicates a species that was not listed in the documentation that we consulted although it is known to occur in the specific country). 54 Tanzania Uganda (BemU subtype) Uganda (BedU subtype) indicator species indicator species indicator species indicator species indicator species indicator species indicator species indicator species indicator species indicator species indicator species indicator species indicator species indicator species indicator species indicator species indicator species indicator species indicator species indicator species indicator species indicator species indicator species indicator species indicator species indicator species indicator species indicator species indicator species indicator species indicator species indicator species indicator species indicator species characteristic species characteristic species characteristic species characteristic species characteristic species characteristic species characteristic species characteristic species characteristic species characteristic species characteristic species characteristic species characteristic species Rwanda Acokanthera schimperi Allophylus africanus Aloe kedongensis Aspilia mossambicensis Azima tetracantha Canthium keniense Capparis fascicularis Capparis tomentosa Carissa spinarum Croton dichogamus Dodonaea viscosa Dombeya burgessiae Dracaena ellenbeckiana Erythrococca bongensis Euclea divinorum Euphorbia candelabrum Gnidia subcordata Grewia bicolor Grewia similis Maerua triphylla Maytenus heterophylla Olea europaea Psiadia punctulata Psydrax schimperiana Pterolobium stellatum Rhus natalensis Scutia myrtina Tarchonanthus camphoratus Tarenna graveolens Tinnea aethiopica Turraea mombassana Turraea nilotica Vepris simplicifolia Vernonia brachycalyx Acacia drepanolobium Acacia gerrardii Acacia hockii Acacia kirkii Acacia senegal Acacia seyal Calodendrum capense Cissus quadrangularis Cissus rotundifolia Cussonia holstii Drypetes gerrardii Elaeodendron buchananii Grewia tembensis Kenya (BewK subtype) Regional status Kenya (BeeK subtype) SPECIES Ethiopia Table 14. Species composition for Evergreen and semi-evergreen bushland and thicket (synonym: evergreen bushland, Be) C f x f x f x x x f f f f x f C f f f f f C C f C f f x f f C x f f f f C x f x f f f f f f f f f C f x x x x x x x x x f x x x x x x x x x x x x x x x x x f x f C C C x x x x x f x x x x f x x x x x x x f f x x x x x x x f x x x x x x x x x x x f x x x x C f x x x f f f x C C x f f x x f C x x C x f x x x x f f f f x x C x f f f f f f f x x f f f f x x f f x f f x f f f x f f C f f f x f f x f f f f f f f f f x f f x f f f f f x x f f C f f f x x x f f x x f f f C f f f f f f f f x f f f f f C f x f f f f f x x f f x x f C f f x f f 55 56 not characteristic not characteristic not characteristic characteristic genus f f f f f f f C C f f f f x C f x f x f f f f f x f f C x f f f f f f Rwanda f f f C x f f x x f C f x x x x f f f f x f x f f x x f f x x x x x x x x x x f x x x x x x x x x x f f x f x f x f x x f x x x f f x x f f f x x x f f x f f x Uganda (BedU subtype) characteristic genus not characteristic x f x C x C x x f x f f x x f x x f f f x f f x x x x x f x x x x f x x x x x x x x x x x x x Uganda (BemU subtype) not characteristic not characteristic C f C f f f f f Tanzania characteristic species characteristic species characteristic species Kenya (BewK subtype) Juniperus procera Sarcostemma viminale Schrebera alata Acacia brevispica Acacia lahai Acacia mellifera Acacia nilotica Acacia polyacantha Acokanthera oppositifolia Albizia amara Albizia coriaria Albizia zygia Allophylus rubifolius Annona senegalensis Antidesma venosum Apodytes dimidiata Balanites aegyptiaca Berberis holstii Berchemia discolor Boscia angustifolia Bridelia micrantha Bridelia scleroneura Cadaba farinosa Canthium lactescens Catha edulis Clausena anisata Clerodendrum myricoides Combretum molle Commiphora africana Cordia monoica Crotalaria agatiflora Croton macrostachyus Cussonia arborea Dichrostachys cinerea Dombeya rotundifolia Dovyalis abyssinica Erythrina abyssinica Euclea racemosa Euphorbia tirucalli Faurea rochetiana Faurea saligna Ficus glumosa Flacourtia indica Gardenia ternifolia Grewia mollis Harrisonia abyssinica Indigofera swaziensis Kenya (BeeK subtype) Regional status Ethiopia SPECIES f f f f x f f f f f C f f f f f C f f x f f f f f f f f f f f f f f f f f f f f f x f f f f f x x f f x f f f f f f x f C f f f f f f f f f f f f f x x f f f f f C x f x f x f f f f x f f x f C f f f f f f x f f f f x f f f f x f f f f f C C f f f C f f f f f f f f f f f f f f f f characteristic genus (synonym: Teclea) characteristic genus (synonym: Teclea) x f f C f f f Uganda (BedU subtype) f f C f C C f f f f x Uganda (BemU subtype) f f f Tanzania f f f Rwanda not characteristic Kenya (BewK subtype) Lannea fulva Lannea humilis Lannea schweinfurthii Lecaniodiscus fraxinifolius Lippia kituiensis Maytenus senegalensis Maytenus undata Oncoba spinosa Ormocarpum kirkii Osyris lanceolata Ozoroa insignis Pappea capensis Pavetta crassipes Pistacia aethiopica Pittosporum viridiflorum Rhamnus staddo Rhoicissus revoilii Rhoicissus tridentata Rhus vulgaris Senna didymobotrya Solanecio cydoniifolius Solanecio mannii Steganotaenia araliacea Stereospermum kunthianum Strychnos henningsii Terminalia brownii Tetradenia riparia Vangueria apiculata Vangueria infausta Vangueria madagascariensis Vepris nobilis Vepris trichocarpa Zanthoxylum chalybeum Zanthoxylum usambarense Ziziphus abyssinica Ziziphus mucronata Ziziphus pubescens Regional status Kenya (BeeK subtype) Ethiopia SPECIES f x x x x x x x x x x x x x x x f x x x x x f x x x x x x x x x x f x x x f f f x x f f x f f x x x f f f x x x f f f x x f x x x x x x x f f f f x f f f f f f f f x f f f f f f f f f f f f x f f f f f f x x f f f x x x x x x f x x x x x x f x x f f x x x x x f f f f f f C C f f f x f f f f f f f f f f f f f f f x f f f f f f f f f f f f f f f f x f f f f x x f f x f x C f f f f f x x f f x C f f 57 15. Montane Ericaceous belt (easily identifiable type, E) 15.1. Description White (1983) refers to Afromontane evergreen bushland and thickets that occur on most of the higher African mountains and that characteristically occupy a large part of the Ericaceous mountain belt. They are also found on the crests and summits of smaller mountains (especially those that are situated close to the ocean or a large lake) or locally on shallow soils within the Afromontane forest belt. Where the ground is not very rocky and has been protected for several years, such as on wetter mountains as the Ruwenzori Mts., almost impenetrable thickets of 3 to 13 m are formed. On drier and rocky slopes, the vegetation is an open community of bushes that is often discontinuous and merges into Afromontane shrubland (see below). Afromontane evergreen bushland and thicket varies greatly in floristic composition, but species of the Blaeria, Erica and Vaccinium Ericaceae genera are nearly always present and sometimes exclusively dominant (White 1983 p. 167 - 168). Hedberg (1951 cited in Friis et al. 2010 p. 113) has documented that an Ericaceous belt occurs on all the high mountains of eastern Africa. Afromontane shrubland occurs on shallow soils and especially exposed rocky ridges. It is much shorter than Afromontane evergreen bushland and thicket and contains stunted invididuals that are dominant in the latter vegetation type. However, Afromontane shrubland also contains species that are usually absent from Afromontane evergreen bushland and thicket (White 1983 p. 168). Ericaceous vegetation occurs at a few places on the East African coast. Evergreen bushland dominated by Erica (synonym: Philippia) occurs on waterlogged sites of former lagoons or lake basins (White 1983 p. 188). Interestingly, Syzygium cordatum is an associate that is listed both for Ericaceous vegetation on Mafia and Pemba islands (White 1983 p. 189) and for tall “elfin” thickets (3 - 7 m) that occur on peaks in the Uluguru mountains (White 1983 p. 168). We did not include coastal Ericaceous vegetation types into the “montane Ericaceous belt” as coastal vegetation is clearly not associated with mountains. 58 Figure 15.1. Ericaceous belt with Erica arborea forming woodland. The floor is completely covered by ferns, mosses and grasses. Bale Mountains (Ethiopia). Approximate altitude 3600 m. Photograph by I. Friis and Sebsebe Demissew (September 2005). Reproduced from Biologiske Skrifter of the Royal Danish Academy of Sciences and letters, Vol. 58, Fig 29A. 2010. Figure 15.2. Ericaceous belt with Erica arborea forming woodland. This location has more grass than the location shown in Fig EA. Bale Mountains (Ethiopia). Approximate altitude 3300 m. Photograph by I. Friis and Sebsebe Demissew (September 2005). Reproduced from Biologiske Skrifter of the Royal Danish Academy of Sciences and letters, Vol. 58, Fig 29C. 2010. Figure 15.3. Ericaceous belt with burnt vegetation. Numerous shoots (green) appear from the burnt stumps of Erica arborea. In between the Erica arborea stumps and in the foreground, the subshrub Alchemilla haumannii (greyish-green) can be seen. Bale Mountains (Ethiopia). Approximate altitude 3800 m. Photograph by I. Friis and Sebsebe Demissew (September 2005). Reproduced from Biologiske Skrifter of the Royal Danish Academy of Sciences and letters, Vol. 58, Fig 29B. 2010. 59 Left: Figure 15.4. The montane Ericaceous belt on Mt. Kahuzi (Kahuzi-Biega-National Park, D.R.Congo. Photograph by E. Fischer (October 1991). Right: Figure 15.5. Vaccinium stanleyi, one of the Ericaceae species of the Ericaceous belt in Rwanda. (Mt. Kahuzi, Kahuzi-Biega-National Park, D.R.Congo). Photograph by E. Fischer (October 1991). Figure 15.6. Erica kingaensis subsp. rugegensis, one of the Erica species of the Ericaceous belt in Rwanda. Rwasenkoko Swamp, Nyungwe National Park. Photograph by E. Fischer (October 1985). Figure 15.7. Profile diagram of Afromontane Ericaceous bushland (“fruticée sclérophylle à Ericaceae”, i.e. sclerophyl scrubland with Ericaceae). This image was the only profile diagramme mentioned by White (1983 p. 167) for Afromontane evergreen bushland and thicket. Vegetation similar to the Ericaceous belt occurs on the crests and summits of some smaller mountains as shown below. Lewalle (1972, Fig. 28). Figure obtained from URL URL: http://www. jstor.org/stable/3667406 60 15.2. Species composition (Please check the methodology and information from Volumes 2 - 5 for more details on how the information on species composition for the different manifestations of this potential natural vegetation type was compiled. In composition tables, "x" indicates that the species is expected to be present, "C" indicates that the species was identified as characteristic species and "f" indicates a species that was not listed in the documentation that we consulted although it is known to occur in the specific country). Tanzania Uganda Ericaceae Ericaceae Ericaceae Ericaceae Ericaceae Ericaceae Ericaceae Ericaceae Ericaceae Rwanda Ericaceae Malawi Adenocarpus mannii Agauria salicifolia Berberis holstii Clematis simensis Discopodium eremanthum Dombeya torrida Erica arborea Erica benguelensis Erica johnstoniana Erica johnstonii Erica kingaensis Erica milanjiana Erica rossii Erica trimera Erica whyteana Faurea saligna Gnidia glauca Hagenia abyssinica Hypericum revolutum Morella salicifolia Rapanea melanophloeos Rhus glutinosa Regional status Kenya SPECIES Ethiopia Table 15. Species composition for Montane Ericaceous belt (easily identifiable type, E) x f x x x x C x C x x x x C f f f f f C C f f f f f C f f f f f f f x C C x x f f C f f f f f f f x C x x C x C x C C f x x x x x f f f f f f C f f f f f f x f f f f C x f f x f 61 16. Afroalpine vegetation (A) 16.1. Description The vegetation of the highest mountains of tropical Africa (≥ 3800, including the Aberdares [Kenya], Mt. Elgon [Kenya and Uganda], Mt. Kenya, Mt. Kilimanjaro [Tanzania], Mt. Meru [Tanzania], the Ruwenzori Mts. [Uganda and DRC], the Virunga Mts. [Rwanda and DRC] and the higher peaks of Ethiopia [but see section 3.2]) are characterized by the occurrence of Giant Senecio species (up to 6 m; Senecio subgenus Dendrosenecio), Giant Lobelia species (up to 6 m), shrubby Alchemilla species and other plants of remarkable lifeforms. Since most of the species also occur in the montane Ericaceous (E, see Volume 3) and Afromontane forest belts (Fa, Fb and Fd, see Volume 2), Afroalpine vegetation can be regarded as an archipelago-like floristic region of extreme floristic impoverishment (White 1983 p. 169). Afroalpine vegetation occurs on high mountains where night frosts are liable to occur throughout the year (White 1983 p. 46). Knox and Palmer (1993, Fig 3) provide the following distribution pattern of the 11 species of giant Senecio species(7): • Senecio subgenus Dendrosenecio adnivalis: Ruwenzori Mts. • Senecio subgenus Dendrosenecio battiscombei: Aberdares and Mt. Kenya • Senecio subgenus Dendrosenecio brassiciformis: Aberdares • Senecio subgenus Dendrosenecio cheranganiensis: Cherangani Hills • Senecio subgenus Dendrosenecio elgonensis: Mt. Elgon • Senecio subgenus Dendrosenecio erici-rosenii: Ruwenzori,Virunga and Mitumba Mts. • Senecio subgenus Dendrosenecio johnstonii: Mt. Kilimanjaro • Senecio subgenus Dendrosenecio keniensis: Mt. Kenya • Senecio subgenus Dendrosenecio keniodendron: Aberdares and Mt. Kenya • Senecio subgenus Dendrosenecio kilimanjari: Mt. Kilimanjaro • Senecio subgenus Dendrosenecio meruensis: Mt. Meru 7: Based on analysis of chloroplast DNA, these authors suggest that the Dendrosenecio subgenus originated on Mt. Kilimanjaro 62 Figure 16.1. Afroalpine vegetation in the foreground with rosettes of Lobelia rhynchopetalum (before flowering). In the background the montane Ericaceous belt (see Volume 2) on the slope of the valley with Erica arborea. Semien mountains (Ethiopia). Photograph by I. Friis and Sebsebe Demissew (October 2009). Reproduced from Biologiske Skrifter of the Royal Danish Academy of Sciences and letters, Vol. 58, Fig 30A. 2010. Figure 16.2. Mosaic of grass sward and Helichrysum crispinum heath together with flowering and sterile individuals of Lobelia rhynchopetalum. Bale mountains (Ethiopia). Photograph by I. Friis and Sebsebe Demissew (September 2005). Reproduced from Biologiske Skrifter of the Royal Danish Academy of Sciences and letters, Vol. 58, Fig 30C. 2010. Figure 16.3. Afroalpine vegetation in the Ruwenzori Mts (Uganda). Photograph by M. Namaganda (June 2008). 63 Figure 16.4. Afroalpine vegetation in the Ruwenzori Mts (Uganda). Photograph by M. Namaganda (June 2008). Figure 16.5. Afroalpine vegetation on the Karisimbi Volcano (Rwandan side of the Virunga Mts.). Photograph by E. Fischer (October 1991). Figure 16.6. Typical East African bird species that occur in Afroalpine vegetation within their natural habitat. Shell guide to East African birds (1960; reproduced with permission from URL http://ufdc.ufl.edu/UF00077050). 64 16.2. Species composition (Please check the methodology and information from Volumes 2 - 5 for more details on how the information on species composition for the different manifestations of this potential natural vegetation type was compiled. In composition tables, "x" indicates that the species is expected to be present, "C" indicates that the species was identified as characteristic species and "f" indicates a species that was not listed in the documentation that we consulted although it is known to occur in the specific country). x x x x Uganda characteristic (genus) characteristic (genus) characteristic (genus) characteristic (genus) characteristic (genus) characteristic (genus) characteristic (genus) characteristic (genus) characteristic (genus) characteristic (genus) characteristic (genus) characteristic (genus) characteristic (genus) characteristic (genus) characteristic (genus) Tanzania Alchemilla argyrophylla Alchemilla elgonensis Alchemilla johnstonii Lobelia deckenii Lobelia rhynchopetalum Lobelia stuhlmannii Lobelia telekii Lobelia wollastonii Senecio myriocephalus Senecio subgenus Dendrosenecio adnivalis Senecio subgenus Dendrosenecio elgonensis Senecio subgenus Dendrosenecio johnstonii Senecio subgenus Dendrosenecio keniodendron Senecio subgenus Dendrosenecio kilimanjari Senecio subsessilis Adenocarpus mannii Erica arborea Helichrysum formosissimum Hypericum revolutum Rwanda Regional status Kenya SPECIES Ethiopia Table 16. Species composition for Afroalpine vegetation (A) f x f x C f C C C C C C C C C f x f C C x C f f x C f C x f x f C f f f f f f f C f 65 17. Afromontane bamboo (B) 17.1. Description Sinarundinaria alpina (synonym: Arundinaria alpina) is one of the four bamboo species (giant grasses with erect woody stems of 2 - 20 m [or even taller] that sometimes form pure and virtually impenetrable communities, and that persist for several years, then flower gregariously and then die back,) that are indigenous to Africa (the other species are Oxytenanthera abyssinica [mapped in the VECEA map as “L”, see below], Oreobambos buchwaldii [it was recorded within species assemblages for various forest vegetation types] and Arundinaria tessellata [current name: Thamnocalamus tessellatus; it replaces Sinarundinaria alpina in South Africa]). Sinarundinaria alpina occurs on most of high mountains of East Africa (Ethiopia to southern Tanzania), but south of Tanzania it is only known to occur on the North Viphya Plateau (Malawi), Dedza Mt. (Malawi) and Mt. Mulanje (Malawi); White 1983 pp. 55 and 166). The Flora Zambesiaca confirms that Sinarundinaria alpina does not occur in Zambia. The species presently does not occur on the North Viphya Plateau (C. Dudley, personal observations). In East Africa, Sinarundinaria alpina is mostly found between 2400 and 3000 m, although it ascends on Mt. Kenya to 3500 m and descends in the Uluguru Mts. (Tanzania) to 1630 m. It grows most vigorously on deep volcanic soils and gently slopes where the annual rainfall exceeds 1250 mm. The largest areas are found on the Aberdare Range (Kenya, 65000 ha), the Mau Range (Kenya, 51000 ha) and Mt Kenya (39000 ha; White 1983 p. 166). Sinarundinaria alpina does not form a belt on Mt. Kilimanjaro, whereas a bamboo belt occurs on the adjacent Mt. Meru (White 1983 p. 167).(8) Hemp (2006) provides the following speculations about the absence of the bamboo zone on Mt. Kilimanjaro: “Another feature of the forests of Kilimanjaro is the absence of a bamboo zone, which occurs on all other tall mountains in East Africa with a similarly high rainfall. Observations on other East African mountains showed that the occurrence of bamboo is linked to a special type of disturbance: the activity of large herbivores. Sinarundinaria alpina stands are favoured by elephants and buffaloes. On Kilimanjaro these megaherbivores occur on the northern slopes, where it is too dry for a large bamboo zone to develop. They are excluded from the wet southern slope forests by topography and humans who have cultivated the foothills for at least 2000 years. From studies on Mt Kenya (Vanleeuwe and Lambrechts [1999]) it is known that elephants climb slopes only up to a steepness of about 30 degrees. On the south-western and north-eastern slopes of Kilimanjaro, very deep (up to several 100 m) and very steep (>30 degree) valleys exist, which reach high up into the alpine zone. These deep gorges prevent large herbivores migrating from the northern side of the mountain to the southern. Combined with human occupation of the wetter slopes, this 66 8: Friis et al. 2010 (p. 95) mention that Hedberg only recorded distinct mountain bamboo zones from the Aberdares, Mt. Elgon, Mt. Kenya, Mt. Meru, Ruwenzori Mts., and Virungu Mts. means that the southern and south-eastern montane forests of Mt Kilimanjaro are no longer accessible for buffaloes and elephants. This interplay of biotic and abiotic factors could explain not only the lack of a bamboo zone on Kilimanjaro but also offers possible explanations for the patterns of diversity and endemism.” Various tree species occur scattered within the bamboo. These tree species probably became established when bamboo plants died following their gregarious flowering (White 1983 p. 167). Figure 17.1. Afromontane bamboo (Sinarundinaria alpina; synonym: Arundinaria alpina) in Kabatwa (Volcanoes National Park, Rwanda). Photograph by V. Minani (October 2009). Figure 17.2. Afromontane bamboo (Sinarundinaria alpina; synonym: Arundinaria alpina) on Mt. Elgon, Ugandan side. Photograph by E.Fischer (October 1997). 67 Figure 17.3. Edge of thicket of Afromontane bamboo (Sinarundinaria alpina; synonym: Arundinaria alpina) near Masha (Ethiopia). In the national reference for Ethiopia, Afromontane bamboo was not described separately from Afromontane forest types in which Afromontane bamboo occurs; this image was included with images for Afromontane rain forest (Fa). Photograph by I. Friis and Sebsebe Demissew (September 2005). Reproduced from Biologiske Skrifter of the Royal Danish Academy of Sciences and letters, Vol. 58, Fig 25E. 2010. Figure 17.4. Edge of thicket of Afromontane bamboo (Sinarundinaria alpina; synonym: Arundinaria alpina) after mass-flowering near Masha (Ethiopia). In the national reference for Ethiopia, Afromontane bamboo was not described separately from Afromontane forest types in which Afromontane bamboo occurs; this image was included with images for Afromontane rain forest (Fa). Photograph by I. Friis and Sebsebe Demissew (January 2009). Reproduced from Biologiske Skrifter of the Royal Danish Academy of Sciences and letters, Vol. 58, Fig 25F. 2010. 68 17.2. Species composition (Please check the methodology and information from Volumes 2 - 5 for more details on how the information on species composition for the different manifestations of this potential natural vegetation type was compiled. In composition tables, "x" indicates that the species is expected to be present, "C" indicates that the species was identified as characteristic species and "f" indicates a species that was not listed in the documentation that we consulted although it is known to occur in the specific country). Tanzania Uganda dominant characteristic characteristic characteristic characteristic characteristic characteristic characteristic characteristic characteristic characteristic characteristic characteristic Rwanda Sinarundinaria alpina Cornus volkensii Dombeya torrida Faurea saligna Hagenia abyssinica Ilex mitis Juniperus procera Lepidotrichilia volkensii Nuxia congesta Podocarpus latifolius Prunus africana Rapanea melanophloeos Tabernaemontana stapfiana Agauria salicifolia Hypericum revolutum Peddiea fischeri Rhamnus prinoides Rubus apetalus Sambucus ebulus Schefflera volkensii Malawi Regional status Kenya SPECIES Ethiopia Table 17. Species composition for Afromontane bamboo (B) f D C x f C f f C x x f x f x C x x x x C f f f f f f f f f f f f f f f D f f f f x D C C C C C C C C C C C C f f f f f f f D f C x C C f x x C f C f x x x x x f f f f f f f f f f f f f f f f f f f f f x f x f f x f 69 18. Fresh-water swamp (X) 18.1. Description Permanent swamps occur in depressions where water permanently floods the surface to a shallow depth (seasonal swamps are usually covered with edaphic grassland [see g]). Most of the shallower lakes outside the GuineoCongolian floristic region (especially those that are not strongly saline, see halophytic vegetation [Z]) have a wide belt of reed-swamp where the dominant species are usually rooted in the soil and have stems that rise out of the water (inside the Guineo-Congolian region, most swampy areas are covered with swamp forest [fs]). The most abundant reed-swamp species is Cyperus papyrus (a giant sedge species) but other species can also be dominant such as Miscanthus violaceus, Phragmites australis and Phragmites mauritianus grasses (White 1983 pp. 55 and 265). True aquatic species occur in deeper water beyond the reed swamp and are either completely submerged or have floating leaves. A belt of floating grasses (principally Vossia cuspidata, Paspalidium germinatum and Panicum repens, but often invaded by Cyperus papyrus) frequently separates the reed-swamp from the aquatic vegetation (White 1983 p. 55). Towards the landward margin of reed-swamp, often a narrow zone occurs of small trees and shrubs that are adapted to swamp conditions. The principal species are Aeschynomene elaphroxylon, Aeschynomene pfundii, Ficus trichopoda (scattered juveniles of swamp-forest trees), Ficus verruculosa (scattered juveniles of swamp-forest trees), Kotschya africana, Mimosa pigra, Sesbania sesban and Syzygium cordatum (scattered juveniles of swampforest trees; White 1983 p. 266). 70 Figure 18.1. Freshwater swamp in Morogoro District (Tanzania). Photograph by H. N. Moshi (2010). Figure 18.2. Freshwater swamp dominated by Cyperus papyrus west of Mbale Town (Uganda). Photograph by J. Kalema (November 2010). Figure 18.3. Freshwater swamp in Rwanda occurring at medium altitudes in that country in Akanyaru. Photograph by C. K. Ruffo (October 2009). 71 Figure 18.4. Typical East African birds of freshwater swamps and lakes within their natural habitat. Shell guide to East African birds (1960; reproduced with permission from URL http://ufdc.ufl.edu/UF00077050). 72 18.2. Species composition (Please check the methodology and information from Volumes 2 - 5 for more details on how the information on species composition for the different manifestations of this potential natural vegetation type was compiled. In composition tables, "x" indicates that the species is expected to be present, "C" indicates that the species was identified as characteristic species and "f" indicates a species that was not listed in the documentation that we consulted although it is known to occur in the specific country). Cyperus papyrus Dissotis rotundifolia Echinochloa pyramidalis Echinochloa stagnina Eichhornia crassipes Ficus verruculosa Heterotis canescens Hibiscus diversifolius Ipomoea rubens Kotschya africana Leersia hexandra Lemna perpusilla Loudetia phragmitoides Ludwigia leptocarpa Ludwigia octovalvis Ludwigia stolonifera Melanthera scandens Mikania capensis Miscanthus violaceus Nymphaea lotus Nymphaea nouchali Oryza longistaminata Pennisetum macrourum Persicaria decipiens Phoenix reclinata Phragmites mauritianus Pistia stratiotes Pycreus mundtii Sesbania bispinosa Sesbania sesban Syzygium cordatum Typha domingensis Typha latifolia Utricularia gibba Vallisneria spiralis Vigna luteola Voacanga thouarsii Vossia cuspidata submerged community in deeper water beyond the reed swamp f f the main constituent of most of the shallower lakes (except those that are strongly saline) outside the Guineo‐Congolian region (where swamp forests are more prominent); also in floating mats principal associate of papyrus species rooted in Vossia cuspidata mats (grass) species rooted in Vossia cuspidata mats (grass) free‐floating species, pest introduced from tropical America (the water hyacinth) juveniles of swamp‐forest trees on the landward margin of reed‐swamp associate of Miscanthus violaceus in shallower lakes in which papyrus is absent principal associate of papyrus trees on the landward margin of reed‐swamp associate of Miscanthus violaceus in shallower lakes in which papyrus is absent (grass) free‐floating species in shallow water on the landward side of papyrus swamp (grass) principal associate of papyrus principal associate of papyrus principal associate of papyrus principal associate of papyrus principal associate of papyrus in shallow water on the landward side of papyrus swamp; also forms a distinct zone in shallower water from which papyrus is absent (grass) community with floating leaves in deeper water beyond the reed swamp community with floating leaves in deeper water beyond the reed swamp (grass) (grass) (palm species) common in silted areas and lakes of volcanic origin in East Africa (grass) free‐floating species trees on the landward margin of reed‐swamp juveniles of swamp‐forest trees on the landward margin of reed‐swamp locally replaces papyrus at higher altitudes associate of Miscanthus violaceus in shallower lakes in which papyrus is absent submerged community in deeper water beyond the reed swamp principal associate of papyrus floating mat at the edge of reed‐swamps, also pioneer of reed‐swamp f f f f x f x x f f f x f f f f f f f x f C f x x f x x f f x f f f C C x x f x x x x x f f f C f f f f f f f f f f f f f f f f f f f f f C C C f f C x C f f f C f f f x x x f f f f f f f f f f f f Zambia C f f f f f Rwanda x f f x x f x Tanzania x x x x x x f f Uganda trees on the landward margin of reed‐swamp trees on the landward margin of reed‐swamp x C C C C Kenya Acacia xanthophloea Aeschynomene abyssinica Aeschynomene cristata Aeschynomene elaphroxylon Aeschynomene pfundii Aeschynomene schimperi Ceratophyllum demersum Cissampelos mucronata Cyperus latifolius Regional status Malawi SPECIES Ethiopia Table 18. Species composition for Fresh-water swamp (X) C x C x x C x x C f C x x x x x f f C f f f x x C C f f x x f f f C f f f f f f C f f f f f f f f f f f f x f f f f f f C C f C f f f 73 19. Edaphic grassland on drainageimpeded or seasonally flooded soils (edaphic vegetation type, g) 19.1. Description White (1983)did not strictly apply a differentiation between edaphic wooded grassland (with cover percentages of 10 - 40% woody species) and edaphic grassland (with cover percentages of <10% woody species) since both types intergrade and edaphic wooded grasslands are often difficult to delimit from the more open grasslands with which they are associated (White 1983 pp. 50 - 52). Within the VECEA map, we loosely (9) defined “edaphic wooded grassland” as “edaphic grassland with scattered woody species” and “edaphic grassland” as “edaphic grassland without scattered woody species”. This means that some vegetation types that would have been classified as “edaphic grasslands” in a strict physiognomic classification system (i.e. woody cover < 10%) may have been allocated to “edaphic wooded grasslands”. The most widespread edaphic grasslands are those associated with seasonally or permanently waterlogged soils. They are limited in areas with short or no dry seasons (such as the Guineo-Congolian floristic region), but are widespread in regions which experience strongly seasonal rainfall (such as the Indian Ocean coastal belt and the Somalia-Masai, Sudanian and Zambezian floristic regions). Waterlogged soils usually occur in depressions which receive more water than is supplied by incident rainfall, but sometimes parent material has an overriding effect such as on edaphic grasslands that occur on volcanic soils (mapped as a distinct VECEA subtype [gv]; White 1983 p. 51). Alkaline grasslands that occur in basins are considered to be halophytic vegetation (mapped separately in VECEA as Z; White 1983 p. 100). Although White (1983) described edaphic grasslands and wooded grasslands separately for the various floristic regions, we did not apply a floristic classification system to edaphic grasslands and edaphic wooded grasslands in the VECEA map. Zambezian edaphic grassland(10) is widespread and occurs principally in four habitats: (i) seasonally waterlogged depressions on the Central African Plateau that are covered with edaphic grassland (“dambos”); (ii) flood plains of rivers and basins with internal drainage; (iii) Kalahari Sand of low relief; and (iv) sandy edges of dambos (White 1983 pp. 99 - 101): Dambo grassland occurs above 1200 m and where there is seasonal flooding (some parts remain boggy throughout the year). The vegetation is usually a medium-dense grass mat of rather uniform appearance and height (50 to 100 cm with flowering culms of 1 to 2 m). Loudetia simplex is the most characteristic grass species and is dominant over large areas (White 1983 pp. 99 - 100). 74 9: among the exceptions that we made to the general rule, we did not include suffrutex grassland among wooded grassland types and neither did we include edaphic grassland on volcanic soils (gv) among wooded grassland types (although scattered Acacia mellifera may occur). 10: edaphic grasslands were studied in detail in several places because swarms of red locusts (Nomadacris septemfasciata) only originate from certain edaphic grassland areas. Four recognized major outbreak areas of the red locust are the Mweru-waNtipa depression in Zambia and the Rukwa valley, the Malagarasi drainage basin and the Wembere de¬pression in Tanzania (Vesey-Fitzgerald 1963). Flood-plain grassland occurs in the valleys of larger rivers where erosion has covered the valley floors with alluvium (mostly heavy clay) and where seasonal rainfall results in seasonal waterlogging. These valleys are covered with a complex and constantly changing mosaic of edaphic grassland, permanent swamp vegetation (X) and termite-mound thickets (“bush groups”, see termitary vegetation [T]), which makes it very difficult to impossible to map these types separately. Floodplain grasslands can be subdivided into wetter types and better-drained types. The most extensive areas of floodplain grasslands of the Zambezian region occur in the Lake Chilwa basin of Malawi, the Malagarasi and Rukwa valleys of Tanzania, the Bangweulu and Mweru Wantipa basins of Zambia and the Chambeshi, Kafue and Upper Zambezi valleys of Zambia (White 1983 p. 100). Kalahari suffrutex grassland is a short wiry grassland that occurs on oligotrophic Kalahari Sand that is seasonally waterlogged. Trees are virtually absent and have been replaced by rhizomatous geoxylic suffrutices that are usually less than 0.6 m tall. At least under the present conditions, their stems are burnt back to ground level every year. The underground parts are usually of massive proportions and greatly exceed the phytomass of grasses, so these communities can be described as “underground forests” although above-ground they look like grasslands most of the year. Most of the suffrutex species are closely related to forest or woodland tree or liana species. The most abundant suffrutex is Parinari capensis and the most widespread dominant grasses are Loudetia simplex and Monocymbium ceresiiforme (White 1983 pp. 100 - 101). Widely distributed suffrutices described by Fanshawe (1971 p. 45) to occur in catenary regression stages of Kalahari woodlands include Annona stenophylla, Chamaeclitandra henriqesiana, Diospyros chamaethamnus, Diospyros virgata, Gardenia brachythamnus, Lannea edulis, Leptactina benguelensis, Napoleonaea gossweilleri, Parinari capensis, Pygmaeothamnus zeyheri, Strobilanthopsis linifolia and Strychnos gossweileri. Most of the dambos are fringed by a narrow zone of sparse wiry grassland with abundant geoxylic suffrutices that are similar to Kalahari suffrutex grassland (White 1983 pp. 100 - 101). Fanshawe (1971 p. 52) describes suffrutex wooded grassland that occurs within a catenary sequence from Undifferentiated woodland (Wn) to grassland. Common suffrutices include Annona stenophylla, Astripomoea malvacea, Brackenridgea arenaria, Combretum platypetalum, Cryptosepalum maraviense, Duosperma crenatum, Eriosema englerianum, Fadogia homblei, Gnidia kraussiana, Hibiscus rhodanthus, Ipomoea vernalis, Lannea edulis, Litogyne gariepina, Parinari capensis and Pygmaeothamnus zeyheri. Edaphic grassland in the Somalia-Masai floristic region was classified as edaphic wooded grassland, although treeless plains dominated by Chrysopogon plumulosus were described to occur in Somalia within deciduous bushland (Bd) and water-receiving depressions with black and cracking clays in Central Tanzania are treeless (but they are separated by an ecotone of wooded grassland, however; see edaphic wooded grassland [we]; White 1983 p. 116). 75 Edaphic grassland that occurs on volcanic soils is mapped and described as a distinct subtype (mapping unit gv; see below). Edaphic grassland of the Zanzibar-Inhambane region was described as a edaphic wooded grassland (we) since woody trees occur (although widely scattered; these areas also contain thicket-covered termite mounts [mapping unit T]; White 1983 p. 189). In most Sudanian edaphic grasslands there is an admixture of woody plants (White 1983 p. 107). Edaphic grasslands were not described by White (1983) for the Afromontane floristic region, although he stated that “there are undoubtedly small areas of edaphic grassland” (White 1983 p. 168). No mention is made of edaphic grasslands for the Lake Victoria regional mosaic. 19.2. Species composition (Please check the methodology and information from Volumes 2 - 5 for more details on how the information on species composition for the different manifestations of this potential natural vegetation type was compiled. In composition tables, "x" indicates that the species is expected to be present, "C" indicates that the species was identified as characteristic species and "f" indicates a species that was not listed in the documentation that we consulted although it is known to occur in the specific country). 76 Figure 19.1. Edaphic grassland in Amboseli National Park (Kenya). Photograph by F. Gachathi (2008). Figure 19.2. A typical dambo near Mbala (Zambia) with its centre of open grassland and fringe of small trees. In the background, Miombo woodland (Wm) with Brachystegia microphylla (a species virtually confined to rocky hills and escarpments, White 1983 p. 93). Burtt et al. (1942 p. 79) comment that “a dambo often gives the impression of a wide road through the general monotony of the Brachystegia forest” (i.e. miombo woodland [Wm]). Burtt et al. (1942, Photograph 7). Image obtained from URL: http://www.jstor.org/stable/2256690. Figure 19.3. The “rain pond catena” in Tanzania was classified by the VECEA project as a catena of Somalia-Masai Acacia-Commiphora deciduous bushland and thicket (Bdd) / edaphic grassland on drainage-impeded or seasonally flooded soils (g). Although the water-receiving depressions are typically treeless grasslands, usually they are separated from deciduous bushland (Bd) by an ecotone of wooded grassland that is dominated by gall Acacias (especially A. drepanolium, A. seyal, A. malacocephala and A. pseudofistula; White 1983 p. 116; see also Gillman 1949 p. 29). Gillman (1949, Fig 30; this is one of the photographs that was cited by White (1983 p. 116) for Somalia-Masai edaphic grassland). 77 Table 19. Species composition for Edaphic grassland on drainage-impeded or seasonally flooded soils Monocymbium ceresiiforme 78 Malawi f x Zambia Loudetia simplex Microchloa kunthii f gsU (Uganda subtype) Zambezian edaphic grassland (wetter types of floodplain grasslands) Zambezian edaphic grassland (better‐drained types of floodplain grasslands) Zambezian edaphic grassland (dambo grasslands, suffrutex grasslands) Somalia‐Masai edaphic grassland (clays plains in Somalia) Zambezian edaphic grassland (suffrutex grasslands) (grass) (grass) (grass) (grass) edaphic grasslands of the Serengeti plains Somalia‐Masai edaphic grasslands; edaphic grasslands of the Serengeti plains (sedge) (sedge) (sedge) (grass) (grass) Zambezian edaphic grassland (wetter types of floodplain grasslands) Zambezian edaphic grassland (wetter types of floodplain grasslands) Zambezian edaphic grassland (better‐drained types of floodplain grasslands) (grass) Zambezian edaphic grassland (dambo grasslands) edaphic grasslands of the Serengeti plains (sedge) Zambezian edaphic grassland (dambo grasslands) Zambezian edaphic grassland (dambo grasslands) (grass) Zambezian edaphic grassland (dambo grasslands) (grass) (grass) (grass) Zambezian edaphic grassland (wetter types of floodplain grasslands) (grass) Zambezian edaphic grassland (dambo grasslands, better‐drained types of floodplain grasslands, suffrutex grassland) edaphic grasslands of the Serengeti plains Zambezian edaphic grassland (dambo grasslands, better‐drained types of floodplain grasslands, suffrutex grassland) geU (Uganda subtype) Acroceras macrum Andropogon brazzae Andropogon schirensis Aristida adscensionis Aristida stipitata Bothriochloa bladhii Brachiaria brizantha Brachiaria humidicola Brachiaria jubata Chloris gayana Cynodon dactylon Cyperus dives Cyperus latifolius Cyperus longus Dichanthium annulatum Echinochloa haploclada Echinochloa pyramidalis Echinochloa stagnina Entolasia imbricata Eragrostis atrovirens Erianthus teretifolius Eustachys paspaloides Fimbristylis dichotoma Hyparrhenia bracteata Hyparrhenia diplandra Hyparrhenia filipendula Hyparrhenia newtonii Hyparrhenia nyassae Hyparrhenia rufa Imperata cylindrica Leersia hexandra Loudetia kagerensis gbU (Uganda subtype) Regional status gfT (Tanzania subtype) SPECIES gdT (Tanzania subtype) Kenya (edaphic vegetation type, g) f f C C C f f f f x f f f x f f f f f f x x x x C f f f f f f f f C C f f f f f f f f f f f f C f f f f f f f f f f f f f f f C f f C f f f f f C f f C f f f f f f f x x x f f f f f f f x f x x f f f f f f f f x f f f f C x f x f f f f f f f C f f f f C C C f f f C C f C f f f f f f f f f f f f C f f f f f C f f f f f f f f x x f f f f x x f f f f f x x x x f f x C f C f x C C x x x x x x x x x x x x x x x x x x x 20. 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Botanical Review 28 (1): 1-239. Whittaker, R.J., Araújo, M.B., Jepson, P., Ladle, R.J., Watson, J.E.M, and Willis, K.J. 2005. Conservation Biogeography: assessment and prospect. Diversity and Distributions 11: 3–23. Young, A. 2007. Thin on the Ground: Land Resource Survey in British Overseas Territories. The Memoir Club, Stanhope, UK. 81 Legend Potential Natural Vegetation of Rwanda List of volumes in the series Potential Natural Vegetation Map of Eastern Africa Lillesø J-PB, van Breugel P, Kindt R, Bingham M, Demissew S, Dudley C, Friis, I Gachathi F, Kalema J, Mbago F, Minani V, Mosh HN, Mulumba J, Namaganda M, Ndangalasi HJ, Ruffo C, Jamnadass R. Graudal L. Potential Natural Vegetation Map of Eastern Africa. Volume 1: The Atlas. High resolution maps for Ethiopia, Kenya, Malawi, Rwanda, Tanzania, Uganda and Zambia. 155 pp. ISBN 978-87-7903-550-8 Forest & Landscape Denmark 61-2011. Kindt R, Lillesø J-PB, van Breugel P, Bingham M, Demissew S, Dudley C, Friis I, Gachathi F, Kalema J, Mbago F, Moshi HN, Namaganda M, Ruffo CK, Védaste M, Jamnadass R and Graudal L. Potential Natural Vegetation Map of Eastern Africa. Volume 2. Description and Tree Species Composition for Forest Potential Natural Vegetation Types. Forest and Landscape Denmark. 232 pp. ISBN 978-87-7903-551-5 Forest & Landscape Denmark 62-2011. Kindt R, Lillesø J-PB, van Breugel P, Bingham M, Demissew S, Dudley C, Friis I, Gachathi F, Kalema J, Mbago F, Moshi HN, Namaganda M, Ruffo CK, Védaste M, Jamnadass R and Graudal L. Potential Natural Vegetation Map of Eastern Africa. Volume 3. Description and Tree Species Composition for Woodland and Wooded Grassland Potential Natural Vegetation Types. Forest and Landscape Denmark. 183 pp. ISBN 978-87-7903-5522 Forest & Landscape Denmark 63-2011. Kindt R, Lillesø J-PB, van Breugel P, Bingham M, Demissew S, Dudley C, Friis I, Gachathi F, Kalema J, Mbago F, Moshi HN, Namaganda M, Ruffo CK, Védaste M, Jamnadass R and Graudal L. Potential Natural Vegetation Map of Eastern Africa. Volume 4. Description and Tree Species Composition for Bushland and Thicket Potential Natural Vegetation Types. Forest and Landscape Denmark. 110 pp. ISBN 978-87-7903-553-9 Forest & Landscape Denmark 64-2011. Kindt R, Lillesø J-PB, van Breugel P, Bingham M, Demissew S, Dudley C, Friis I, Gachathi F, Kalema J, Mbago F, Moshi HN, Namaganda M, Ruffo CK, Védaste M, Jamnadass R and Graudal L. Potential Natural Vegetation Map of Eastern Africa. Volume 5. Description and Tree Species Composition for Other Potential Natural Vegetation Types. Forest and Landscape Denmark. 131 pp. ISBN 978-87-7903-555-3 Forest & Landscape Denmark 65-2011. Van Breugel P, Kindt R, Lillesø J-PB, Bingham M, Demissew S, Dudley C, Friis I, Gachathi F, Kalema J, Mbago F, Moshi HN, Namaganda M, Ruffo CK, Védaste M, Jamnadass R and Graudal L. Potential Natural Vegetation Map of Eastern Africa. Volume 6. An Overview of The Methods and Material Used to Develop the Map. 139 pp. ISBN 978-87-7903-562-1 Forest & Landscape Denmark 68-2011. Van Breugel P, Kindt R, Lillesø J-PB, Bingham M, Demissew S, Dudley C, Friis I, Gachathi F, Kalema J, Mbago F, Moshi HN, Namaganda M, Ruffo CK, Védaste M, Jamnadass R and Graudal L. Potential Natural Vegetation Map of Eastern Africa. Volume 7. Projected Distributions of Potential Natural Vegetation Types and Two Important Agroforestry Species (Prunus Africana and Warburgia Ugandensis) for Six Possible Future Climates. 63 pp. ISBN 978-87-7903-563-8. Forest & Landscape Denmark 69-2011. Kindt R, van Breugel P, Lillesø, J-PB, Gachathi F, Omondi W, Jamnadass R, and Graudal L. 2014 Potential Natural Vegetation of Eastern Africa (Ethiopia, Kenya, Malawi, Rwanda, Tanzania, Uganda and Zambia), Volume 8. Atlas and Tree Species Composition for Kenya. 194 pp. ISBN 978-87-7903-616-1 (paper) ISBN 978-87-7903615-4 (digital). Department of Geosciences and Natural Resource Management, University of Copenhagen. Kindt R, van Breugel P, Lillesø, J-PB, Minani V, Ruffo CK, Gapusi J, Jamnadass R and Graudal L. 2014: Potential Natural Vegetation of Eastern Africa. Volume 9. Atlas and Tree Species Composition for Rwanda. 93 pp. ISBN 978-87-7903-619-2 (paper) ISBN 978-87-7903-617-8 (digital). Department of Geosciences and Natural Resource Management, University of Copenhagen. Lillesø, J-PB, van Breugel P, Kindt R, Mbago F, Moshi HN, Ndangalasi HJ, Uronu, LON, Jamnadass R and Graudal L. 2014: Potential Natural Vegetation of Eastern Africa. Volume 10. Atlas and Tree Species Composition for Tanzania. 198 pp. ISBN 978-87-7903-622-2 (paper) ISBN 978-87-7903-620-8 (digital). Department of Geosciences and Natural Resource Management, University of Copenhagen. Van Breugel P, Kindt R, Lillesø J-PB, Kalema J, Mulumba J, Namaganda M, Malinga M, Esegu JFO, Jamnadass R and Graudal L. 2014: Potential Natural Vegetation of Eastern Africa. Volume 11. Atlas and tree species composition for Uganda. 128 pp. ISBN 978-87-7903-624-6 (paper) ISBN 978-87-7903-623-9 (digital). Department of Geosciences and Natural Resource Management, University of Copenhagen. d e pa rt m e n t o f g e o s c i e n c e s a n d n at u r a l r e s o u r c e m a n a g e m e n t university of copenhagen rolighedsvej 23 dk-1958 frederiksberg c denmark tel. +45 353 31500 ign@ign.ku.dk www.ign.ku.dk/ The research was conducted for the CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS) by a team of scientists based at the World Agroforestry Centre, Forest & Landscape Denmark, Makerere University, Entebbe Botanical Gardens, National Tree Seed Centre and National Forestry Resources Research Institute World Agroforestry Centre Nairobi, Kenya www.worldagroforestry.org Forest & Landscape Denmark Frederiksberg, Denmark www.SL.life.ku.dk National Herbarium of Rwanda, Institut de Recherche Scientifique et Technologique (I.R.S.T.) Butare, Rwanda www.irst.ac.rw Rwanda National Tree Seed Centre, Rwanda Agricultural Board (RAB) www.rab.gov.rw With support from: The Rockefeller Foundation www.rockefellerfoundation.org/

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Potential natural vegetation of eastern Africa. Volume 2: Description

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