Woody species of the Miombo woodlands and geoxylic grasslands of the Cusseque area, south-central Angola

Rasmus Revermann; Francisco Maiato Gonçalves; Amândio Luis Gomes; Manfred Finckh

The species composition of the vegetation in most regions of Angola has been poorly studied and most studies date back to the pre-independence era. In this study, we provide a detailed account of the woody flora of the Miombo woodlands and geoxylic grasslands of the Cusseque study site of “The Future Okavango” (TFO) project, situated on the Angolan Central Plateau. The checklist is based on a vegetation survey using vegetation plots of 1,000 m² and also includes records from botanical collections made elsewhere at the study site. In total, we documented 154 woody species belonging to 99 genera of 37 plant families in 100 km². The study represents the first comprehensive account of the woody vegetation of the area including all habitats and growth forms.

Check List Check List 13(1): 2030, Erratum, 24 January 2017 ISSN 1809-127X © 2017 Check List and Authors LISTS OF SPECIES Erratum Woody species of the Miombo woodlands and geoxylic grasslands of the Cusseque area, south-central Angola Rasmus Revermann, Francisco Maiato Gonçalves, Amândio Luis Gomes & Manfred Finckh In Table 1, on page 7, please read “Oleaceae” in place of “Olacaceae”. The authors regret this error. The original, unaltered publication begins on the following page. i the journal of biodiversity data Check List the journal of biodiversity data Check List 13(1): 2030, 6 January 2017 doi: https://doi.org/10.15560/13.1.2030 ISSN 1809-127X © 2017 Check List and Authors LISTS OF SPECIES Woody species of the Miombo woodlands and geoxylic grasslands of the Cusseque area, south-central Angola Rasmus Revermann1, 4, Francisco Maiato Gonçalves1, 2, Amândio Luis Gomes1, 3 & Manfred Finckh1 1 University of Hamburg, Biocentre Klein Flottbek, Department of Biodiversity, Ecology and Evolution of Plants, Ohnhorststr. 18, 22609 Hamburg, Germany 2 Herbarium of Lubango, ISCED-Huíla, Department of Natural Sciences, Rua Sarmento Rodrigues, 230 Lubango, Angola 3 University Agostinho Neto, Faculty of Sciences, Department of Biology, Av. 4 de Fevereiro, Luanda, Angola 4 Corresponding author. E-mail: rasmus.revermann@uni-hamburg.de types and over 100 subordinate types dealt with in the text (Barbosa 1970, 1971). However, the descriptions of these vegetation types were of general character and limited to the dominant species. Detailed descriptions of the species composition and plant diversity of the Angolan vegetation are lacking for most parts of the country. For the province of Bié, Monteiro (1970) provided an excellent overview on the woody vegetation including the first provincial map of the woodlands. Based on 144 relevés, Monteiro delineated three associations of woody plants and four sub-associations. The civil war that followed Angola’s independence in 1975 made any scientific work in Angola extremely difficult, and thus, most scientific literature available today dates back to the pre-independence era. Since the end of the armed conflict in 2002, scientific work is slowly increasing. However, botanical work in the country is still hampered by the lack of field guides and the fact that the principal work on the flora of Angola, the Conspectus Florae Angolensis, remains unfinished and important families such as the Rubiaceae are not treated. Similarly, a countrywide checklist of the flora of Angola was lacking until the recent publication of “Plants of Angola – Plantas de Angola” by Figueiredo & Smith (2008). Nevertheless, inventories of vascular plants at the local and regional scale are still lacking for most parts of the country. Such inventories are indispensable for any kind of natural resource management planning, conservation measures or ecological studies (Figueiredo et al. 2009). The interdisciplinary research project “The Future Okavango” (TFO) aims to provide a scientific basis for strategic resource planning for the Okavango Basin. The headwaters of the Okavango River, where 95% of the runoff are generated, are located on the Angolan Central Plateau (Steudel et al. 2013). Rapid transformations of the social-ecological systems are currently taking place there (Pröpper et al. 2015). However, little knowledge abstract: The species composition of the vegetation in most regions of Angola has been poorly studied and most studies date back to the pre-independence era. In this study, we provide a detailed account of the woody flora of the Miombo woodlands and geoxylic grasslands of the Cusseque study site of “The Future Okavango” (TFO) project, situated on the Angolan Central Plateau. The checklist is based on a vegetation survey using vegetation plots of 1,000 m2 and also includes records from botanical collections made elsewhere at the study site. In total, we documented 154 woody species belonging to 99 genera of 37 plant families in 100 km2. The study represents the first comprehensive account of the woody vegetation of the area including all habitats and growth forms. Key words: Angola; Bié; geoxylic suffrutex; Miombo; The Future Okavango project; vegetation survey INtrODuCtION Rural communities in Angola hold an enormous knowledge of the local flora and especially have great understanding of the potential usages of plants (Figueiredo & Smith 2012; Kissanga 2016). In contrast, scientific exploration and documentation of the vegetation of Angola is still limited. Early botanists such as Friedrich Welwitsch visited the country in the middle of the 19th century (Welwitsch 1869). The most influential botanist working in Angola in the first half of the 20th century was John Gossweiler, who worked in all Angolan provinces and collected over 14,000 specimens. His collection is considered an especially important source of information for rare and endemic species (Figueiredo & Smith 2008). Furthermore, Gossweiler produced the first phytogeographic map of Angola containing 19 principal vegetation types (Gossweiler & Mendonça 1939). Based on this map and his own observations, Luís A. Grandvaux Barbosa published a new phytogeographic map in 1971 containing 32 main 1 Revermann et al. | Woody species of the Cusseque area, south-central Angola season lasting from November to April. The mean annual precipitation is 987 mm and the mean annual temperature is 20.4°C (Weber 2013). The study area harbours a high pedodiversity. The elevated areas are characterized by deep and developed slightly loamy Arenosols. The slopes of the smaller valleys of the tributaries and at the western side of the Cusseque River show shallow Plinthisols on granitic bedrock. The soils along the eastern part of the Cusseque River are characterized by very deep and leached Arenosols. The centre of the valleys support Histosols with peat layers exceeding 1 m in depth while at the edges of the wetlands Gleysols are the common soil type (Gröngröft et al. 2013a). The main vegetation types covering south central Angola are semi-deciduous Miombo woodlands and forests (Figures 2a and b). These woodlands are interspersed with open vegetation types locally termed anharas de ongote. The salient feature of the open vegetation types are dwarf shrubs with a huge underground woody biomass. This distinct life form was described by White (1976) as “geoxylic suffrutex”. In the Cusseque area, geoxylic suffrutices occur on two different soil types: on deep, leached sandy soils and on shallow, compact, ferralitic soils. Accordingly, we will differentiate herein between “geoxylic grasslands on sandy soils” (Figure 2c) and “geoxylic grasslands on ferralitic soils” (Figure 2d). The occurrences of the different vegetation types are governed by topography: woodlands and forests are confined to the elevated areas and upper slopes. The mid- and lower and data on the vegetation and the botanical diversity was available (Revermann 2016). In this study, we present results of the vegetation survey carried out at the research site “Cusseque” in the province of Bié located at the upper reaches of the Okavango River. matErIaLS aND mEtHODS Study site The Okavango River originates on the Angolan Central Plateau and terminates in a large inland delta in the Kalahari Desert in Botswana. Within the TFO project, detailed studies were carried out at four research sites representing the different parts of the river basin. The work presented in this paper was carried out at the study site Cusseque with an area of 100 km2 (13.6985° S, 017.0382° E). The site is located on the Angolan Central Plateau in the province of Bié (Figure 1; Wehberg & Weinzierl 2013). The landscape can be described as a rolling plain intersected by the Cusseque River and its many tributaries, which are orientated perpendicular to each other. Three major landscape units can be identified: the elevated areas, the sloping areas leading down to the valley bottoms and the valley floors (Gröngröft et al. 2013b). The mean elevation is 1,575 m above sea level while the difference in elevation between the valley bottom of the main river and the surrounding elevated areas is about 100 m (Gröngröft et al. 2013b). The climate of the Cusseque area is semi-humid with a pronounced wet Figure 1. Location of the Okavango Basin in southern Africa and the study site “Cusseque” denoted in red. (Projection: WGS 1984; background: RapidEye high-resolution satellite imagery, recorded 1 May 2013. We acknowledge the DLR for the provision of the data from the RapidEye Science Archive.) Check List | www.biotaxa.org/cl 2 Volume 13 | Issue 1 | Article 2030 Revermann et al. | Woody species of the Cusseque area, south-central Angola Figure 2. Landscapes of the Cusseque study area: a) Miombo woodland in the middle of the rainy season, b) Miombo woodland at the end of the rainy season, c) geoxylic grasslands dominated by Cryptosepalum maraviense at the beginning of the rainy season in October, d) geoxylic grassland on sandy soils at the beginning of the dry season in May; in the background wetland on the valley bottom and Miombo woodlands. slopes feature geoxylic grasslands. The woodlands and geoxylic grasslands are separated by ecotones extending up to several hundred meters where elements of both vegetation types co-occur. The valley bottoms support wetlands dominated by Cyperaceae (Revermann et al. 2013; Schneibel et al. 2013). to the unique character of the geoxylic grasslands, these were subject to an additional field study. Therein, data were collected using 10 m × 10 m plots with two 3.3 m × 3.3 m subplots situated in diagonally opposite corners (adapted from Dengler 2009). In every plot all vascular plants found were recorded and their projected cover estimated visually. Unknown plants were photographed and voucher specimens were collected according to botanical methods outlined by Victor et al. (2004). Voucher specimens were deposited in the herbarium of the ISCED Huíla (LUBA) and in the Herbarium Hamburgense (HBG). In addition to the species recorded on the vegetation plots, species found elsewhere while working at the study area were added to the checklist. A high number of vegetation plots and several months of field work carried out by four observers in all seasons ensured a comprehensive coverage of the woody species present at the study area. Data collection Plot based vegetation surveys were carried out during the growing season in the years 2011 to 2014 and all information is stored in the Vegetation Database of the Okavango Basin (GIVD ID: AF-00-009, Revermann et al. 2016). In order to evenly map all existing vegetation units, sampling followed a random, stratified design. Based on an image segmentation algorithm using all bands of a Landsat 7 scene, seven major vegetation units were identified. In these vegetation units random points were created using GIS and transferred to a hand-held GPS for localization in the field. Furthermore, additional vegetation plots were examined in different successional stages of Miombo forest to analyse successional pathways of the regeneration of natural vegetation after disturbance by shifting cultivation (Gonçalves et al., accepted). We used a nested plot design with a 10 m × 10 m plot located in the centre of a 20 m × 50 m plot. In total, we sampled 148 vegetation plots. Due Check List | www.biotaxa.org/cl taxonomy and plant identification We followed the taxonomy of the checklist “Plants of Angola – Plantas de Angola” by Figueiredo & Smith (2008). We are aware of recent changes in the taxonomy, but decided to conform to the national checklist. For identification, we consulted the Conspectus Florae Angolensis (Exell & Mendonça 1937, 1951, 1954, 1955; Exell & Fernandes 3 Volume 13 | Issue 1 | Article 2030 Revermann et al. | Woody species of the Cusseque area, south-central Angola 1962, 1966; Exell et al. 1970) when possible, and the flora of neighbouring countries, especially the Flora Zambeziaca (Exell & Wild 1960) and the field guide to the Trees and shrubs of Namibia (Mannheimer & Curtis 2009). Additionally, we consulted herbarium collections at the ISCED Huíla (LUBA) and the Instituto de Investigação Científica Tropical (LISC) as well as the on-line database JSTOR Plant Science (http://plants.jstor.org/). For some specimens, we consulted experts at Kew Botanical Garden (K). Permits Permits for plant collection and transfer of biological material in Angola for scientific purposes was arranged based on the framework of Material Transfer Agreements from Angola, negotiated between the Instituto Superior de Ciências de Educação da Huíla (ISCED, Huíla), Lubango and the University of Hamburg (UHH), Germany and authorized on behalf of the Angolan Government by the Director for Agriculture, Fisheries and Environment of the Province of Huíla. All International Conventions to which Angola is signatory country, such as Convention on International Trade in Endangered Species of Wild Fauna and Flora (1973), Convention on Biological Diversity (1992), International Treaty on Plant Genetic Resources for Food and Agriculture (2004), and all other relevant national and international instruments concerning biodiversity were taken into account. Figure 3. The families of woody plants found at the Cusseque study site, south-central Angola. Only families with more than two species are shown. In total 37 families of woody plant species occurred, containing 154 species in 99 genera. and forests showed the highest woody species richness with 110 species belonging to 32 families. A surprisingly high number of 33 woody species from 14 families were found in the geoxylic grasslands. These open vegetation types appear to be merely grasslands in the late growing season (Figures 2c and d) but in fact harbour a remarkable diversity of woody species (Table 1). In the wetlands few woody species occurred and we recorded only two Ficus species sporadically occurring along the margins of the wetlands. One species, Combretum schumannii Engl., was recorded but is not listed in the current checklist of Angola (Figueiredo & Smith 2008). Data analysis DISCuSSION We visualized the number of species per family of all species belonging to one family using the function ‘pie’ in the statistical software R (R Development Core Team 2016). Data on the frequency of occurrence of a species, the habitat and the life form were compiled from vegetation plot data. We assigned frequency according to the following categories: very rare (1 or 2 observations), rare (3–5 observations), occasional (6–10 observations), frequent (11–30 observations), common (>30 observations). We assigned every species to one or more of the following life form categories based on field observations and literature: tree, shrub, liana, dwarf shrub and geoxyle. For geoxyles we followed the definition proposed by White (1976). White defined a geoxyle as a dwarf shrub that has closely related species growing as trees and that exhibits massive woody underground parts. The 154 species recorded within the 100 km2 of the Cusseque study site almost equalled the 166 woody species found by Monteiro (1970) in the entire province of Bié, an area of 70,314 km2. This does not reflect the quality of the study of Monteiro but rather illustrates how poorly the region has been surveyed so far. In fact, the study carried out by Monteiro (1970) is of high quality and stands out as the only study of its time from Angola basing its analysis on quantitative, plot based data. However, the study was restricted to woodlands and only larger shrubs and trees were included. In contrast, we included all vegetation types ranging from woodlands to geoxylic grasslands and wetlands. Due to the high sampling intensity and the coverage of all vegetation types our species list can therefore be considered a comprehensive checklist of the woody plant species of the Cusseque area. However, it must be noted that this list does not contain any specimen that could not be identified to at least genus level; some specimens were lacking fruits or flowers, preventing further identification. Therefore, the actual number of woody species may be slightly higher. Despite the relatively recent publication of the checklist of vascular plants of Angola, subsequent field surveys in various parts of the country have resulted in additions to the checklist (Huntley & Coelho 2011). We provided the first record in Angola of the herbaceous Asteraceae Schistostephium crataegifolium (DC.) Fenzl ex Harv, during the rESuLtS We documented 154 woody species belonging to 99 genera and 37 families (Table 1). The majority of species belonged to the family Fabaceae (33), followed by Rubiaceae (22), Euphorbiaceae (11), Proteaceae (10) and Combretaceae (9) (Figure 3). Most of the dominant species belonged to the Fabaceae and occurred with high frequencies. In contrast, the Rubiaceae, second in species richness, contained species occurring with low frequencies and were less abundant. The woodlands Check List | www.biotaxa.org/cl 4 Volume 13 | Issue 1 | Article 2030 Revermann et al. | Woody species of the Cusseque area, south-central Angola Table 1. List of species arranged by family. Voucher specimens have been deposited in the herbaria of Lubango (LUBA) and Hamburg (HBG). In most cases doublets are stored in both herbaria. The herbarium name in parentheses is the location where the specimen used for identification is deposited. Frequency was assigned according to the following categories: very rare (1 or 2 observations), rare (3–5 observations), occasional (6–10 observations), frequent (11–30 observations), common (>30 observations). Life forms of the species were assigned to one or more of the categories: tree, shrub, liana, dwarf shrub and geoxyle. Species name Frequency Life form Habitat Collection number(s) Anacardiaceae Ozoroa cf. xylophylla (Engl. &Gilg) R.Fern. & A.Fern. very rare shrub geoxylic grassland (sandy soils) 133057B (HBG) Ozoroa stenophylla Engl. & Gilg. frequent shrub woodland / grassland (ferralitic soils) 140123 (LUBA) Rhus arenaria Torre, A.R. frequent dwarf shrub / geoxyle geoxylic grassland (ferralitic soils) 140101 (LUBA) Rhus exelliana Meikle frequent dwarf shrub Rhus gracilipes Exell frequent dwarf shrub woodland / forest 139227; 132483 (HBG) 135250; 134275 (HBG) Rhus kirkii Oliv. frequent dwarf shrub woodland / forest 139253 (LUBA) Anisophylleaceae Anisophyllea boehmii Engl. frequent tree woodland / forest 134316; 139018; 135297 (HBG) Anisophyllea quangensis Engl. ex Henriq. rare dwarf shrub geoxylic grassland (sandy soils) 133044; 134116 (HBG); 140109 (LUBA) Annoncaceae Annona stenophylla ssp. nana Engl. & Diels rare dwarf shrub woodland / forest 133058; 134218 (HBG); 140065 (LUBA) Uvaria angolensis Welw. ex Oliv. (Figure 4b) frequent shrub woodland / forest 135323; 134240 (HBG) Xylopia odoratissima Welw. ex Oiv. frequent shrub woodland / forest 133057A; 134263 (HBG) Xylopia tomentosa Exell common shrub woodland / forest 135279; 132956; 132986 (HBG); 139177 (LUBA) common dwarf shrub / geoxyle geoxylic grassland (sandy soils) 140121 (LUBA) Apocynaceae Chamaeclitandra henriquesiana (Hallier f.) Pichon Diplorhynchus condylocarpon (Müll. Arg.) Pichon frequent shrub / tree woodland / forest 135300 (HBG) Landolphia camptoloba (K.Schum.) Pichon frequent liana woodland / forest 132537 (HBG) Landolphia gossweileri (Stapf ) Pichon rare dwarf shrub geoxylic grassland (sandy soils) 133048 (HBG) Strophanthus welwitschii (Baill.) K.Schum. frequent liana woodland / forest 135336; 135378; 134091 (HBG) Asparagaceae Asparagus sp. 135286 frequent shrub woodland / forest 135286 (HBG) Asparagus cf. africanus Lam. very rare shrub woodland / forest 134115 (HBG) occasional shrub woodland / forest 132695 (HBG) Parinari capensis Harv. frequent dwarf shrub / geoxyle geoxylic grassland (sandy soils) 132664; 132898; 140068 (HBG) Parinari curatellifolia Planch. ex Benth. common tree woodland / forest 132444 (HBG) Asteraceae Helichrysum krausii Sch. Bip Crysobalanaceae Combretaceae Combretum acutifolium Exell very rare liana / shrub woodland / forest 135306 (HBG) Combretum collinum Fresen. common tree woodland / forest 139176 (HBG) Combretum elaeagnoides Klotzsch very rare tree woodland / forest 132538 (HBG) Combretum engleri Schinz frequent shrub woodland / forest 133216 (HBG) Combretum platypetalum ssp. platypetalum Welw. ex M.A.Lawson (Figure 4f ) occasional dwarf shrub geoxylic grassland (sandy soils) 132639; 134114; 140113 (HBG) Combretum schumannii Engl. rare shrub woodland / forest 139048 (LUBA) Combretum zeyheri Sond. frequent shrub / tree woodland / forest 135280; 132510 (HBG) Pteleopsis anisoptera (Welw.) Engl. & Diels frequent shrub / tree woodland / forest 135365; 134110 (HBG); 139066 (LUBA) Terminalia brachystemma Welw. ex Hiern frequent tree woodland / forest / grassland (sandy and ferralitic soils) 132997; 134088; 134131 (HBG) frequent dwarf shrub / geoxyle geoxylic grassland (sandy soils) 140165 (LUBA) Dichapetalaceae Dichapetalum cymosum (Hook.) Engl. Dipterocarpaceae Monotes africanus A.DC. common tree woodland / forest 132917; 134160; 134228 (HBG) Monotes angolensis de Wild. very rare tree woodland / forest 132443 (HBG) Monotes caloneurus Gilg. rare tree woodland / forest 134820 (HBG) Monotes dasyanthus Gilg common tree woodland / forest 132907; 132961 (HBG); 139228 (LUBA) Ebenaceae Diospyros batocana Hiern occasional shrub / tree woodland / forest 139247 (LUBA) Diospyros chamaethamnus Dinter ex Mildbr. frequent dwarf shrub / geoxyle geoxylic grassland (sandy soils) 140179 (LUBA) Continued Check List | www.biotaxa.org/cl 5 Volume 13 | Issue 1 | Article 2030 Revermann et al. | Woody species of the Cusseque area, south-central Angola Table 1. Continued. Species name Frequency Life form Habitat Collection number(s) Ebenaceae, continued Diospyros pseudomespilus ssp. brevicalyx Mildbr. Diospyros virgata (Gürke) Brenan Euclea crispa ssp. crispa (Thunb.) Gürke frequent occasional frequent shrub shrub dwarf shrub woodland / forest woodland / forest woodland / forest / geoxylic grassland 135379 (HBG) 132941 (HBG) 135413 (HBG) very rare shrub / tree woodland / forest 139235 (LUBA) occasional frequent rare rare common common occasional frequent common shrub / tree shrub / tree shrub / tree dwarf shrub dwarf shrub dwarf shrub tree dwarf shrub dwarf shrub / geoxyle tree tree woodland / forest woodland / forest woodland / forest woodland / forest woodland / forest woodland / forest woodland / forest woodland / forest geoxylic grassland (ferralitic soils) woodland / forest woodland / forest 139095 (LUBA) 134099; 134135 (HBG); 139068 (LUBA) 139113 (LUBA) 139256 (LUBA) 139238 (LUBA) 139237 (LUBA) 132555; 134232 (HBG); 139038 (LUBA) 132990; 134185 (HBG) 132490; 134199 (HBG) 132691; 132912; 132998 (HBG) geoxylic grassland (sandy soils) 140167 (LUBA) frequent occasional frequent common frequent dwarf shrub / geoxyle tree shrub / tree shrub / tree shrub shrub / tree woodland / forest woodland / forest woodland / forest woodland / forest woodland / forest 134156; 135318 (HBG); 139223 (LUBA) 139065; 135342; 132967 (HBG) 135360; 139242; 133018 (HBG) 135311 (HBG) 132963; 139128 (LUBA) common occasional common common common rare rare rare common tree tree tree tree shrub dwarf shrub dwarf shrub dwarf shrub tree woodland / forest woodland / forest woodland / forest woodland / forest woodland / forest woodland / forest woodland / forest woodland / forest woodland / forest 135298; 139016 (LUBA) 132957; 139255 (LUBA) 132676 (HBG) 132900; 135335 (HBG); 139233 (LUBA) 139121 (LUBA) 139257 (LUBA) 139196 (LUBA) 135304 (HBG); 139023 (LUBA) common dwarf shrub 132754; 132825 (HBG) common dwarf shrub Dalbergia nitidula Welw. ex Baker Dialium englerianum Henriq. Dolichos sp. 140088 rare frequent frequent Entada arenaria Schinz Eriosema sp. 133109 very rare rare shrub / tree shrub / tree dwarf shrub / geoxyle dwarf shrub dwarf shrub Eriosema sp. 132895 rare dwarf shrub Erythrina abyssinica Lam. ex DC. Erythrophleum africanum (Welw. ex Benth.) Harms Guibourtia coleosperma (Benth.) J.Léonard Humularia welwitschii (Taub.) P.A.Duvign. Indigofera baumiana Harms Indigofera congesta Welw. ex Baker Kotschya strobilantha (Welw. ex Baker) Dewit & P. A. Duvign. var. strobilantha Mucuna sp. 140052 very rare common occasional common frequent occasional rare 140052 (LUBA) Pericopsis angolensis (Baker) Meeuwen Pterocarpus angolensis DC frequent occasional tree tree tree dwarf shrub shrub dwarf shrub dwarf shrub / geoxyle dwarf shrub / geoxyle shrub / tree tree geoxylic grassland (ferralitic soils) geoxylic grassland (ferralitic soils) woodland / forest woodland / forest geoxylic grassland (ferralitic soils) geoxylic grassland (sandy soils) geoxylic grassland (ferralitic soils) geoxylic grassland (ferralitic soils) giant termite mounds woodland / forest woodland / forest woodland / forest woodland / forest woodland / forest geoxylic grassland (ferralitic soils) geoxylic grassland (sandy soils) woodland / forest woodland / forest 139181 (LUBA) - Ericaceae Erica benguellensis (Welw. ex Engl.) E.G.H. Oliv. Euphorbiaceae Bridelia sp. 139095 Hymenocardia acida Tul. Maprounea africana Müll. Arg. Phyllanthus angolensis Müll. Arg. Phyllanthus sp. 139238 Phyllanthus welwitschianus Müll. Arg. Pseudolachnostylis maprouneifolia Pax Sclerocroton oblongifolius (Müll. Arg.) Kruijt & Roebers Uapaca sp. 134199 Uapaca kirkiana Müll. Arg. Uapaca nitida var. nitida Müll. Arg. Fabaceae Abrus melanospermus ssp. suffruticosus (Boutique) D.K.Harder Albizia antunesiana Harms Albizia gummifera (J.F.Gmel) C.A.Sm. Baphia bequaertii De Wild. Bauhinia petersiana Bolle Bobgunnia madagascariensis (Desv.) J.H.Kirkbr. & Wiersema Brachystegia bakeriana Hutch. & Burtt Davy Brachystegia longifolia Benth. Brachystegia spiciformis Benth. Burkea africana Hook. Copaifera baumiana Harms Crotalaria amoena Welw. ex Baker Crotalaria cistoides Welw. ex Baker Crotalaria florida Welw. ex Baker Cryptosepalum exfoliatum ssp. pseudotaxus (Baker f.) P.A.Duvign. & Brenan (Figure 4i) Cryptosepalum exfoliatum ssp. suffruticans (P.A.Duvign.) P.A.Duvign. & Bre (Figure 4h) Cryptosepalum maraviense Oliv. (Figure 4g) common common occasional frequent 135308B; 135620 (HBG) 139236 (LUBA) 133147; 139034 (LUBA) 140088 (LUBA) 134147 (HBG) 133109 (HBG) 132753; 132895 (HBG) 135333 (HBG) 139054 (LUBA) 139146 (LUBA) 132530 (HBG) 139237 (LUBA) 139141 (LUBA) Continued Check List | www.biotaxa.org/cl 6 Volume 13 | Issue 1 | Article 2030 Revermann et al. | Woody species of the Cusseque area, south-central Angola Table 1. Continued. Species name Frequency Life form Habitat Collection number(s) Hypericaceae Psorospermum febrifugum Spach. rare shrub / tree woodland / forest 139036 (LUBA) Psorospermum tenuifolium Hook.f. rare shrub / tree woodland / forest 132958 (HBG) common shrub woodland / forest 132968; 133005; 133149 (HBG) Ixonanthaceae Phyllocosmus lemaireanus (De Wild. & T.Durand) T.Durand & H.Durand Lamicaceae Alvesia rosmarinifolia Welw. occasional shrub woodland / forest 134776; 132533 (HBG) Tinnea sp. 133121 frequent dwarf shrub geoxylic grassland (ferralitic soils) 133121 (HBG) Vitex doniana Sweet occasional shrub woodland / woodland ecotone 132915 (HBG) Vitex madiensis Oliv. frequent shrub woodland / woodland ecotone 132996 (HBG); 139069 (LUBA) Melastomataceae Memecylon flavovirens Baker frequent shrub / tree woodland / forest 132519; 133161 (HBG); 139240 (LUBA) Warneckea sapinii (De Wild.) Jacq.-Fél. (Figure 4d) occasional tree woodland / forest 135309 (HBG); 139140 (LUBA) occasional shrub woodland / forest 132546; 133000; 133096 (HBG) Meliaceae Ekebergia benguelensis Welw. ex C.DC. Moraceae Ficus pygmaea Welw. ex Hiern rare dwarf shrub wetland margin 141510 (HBG) Ficus sp. 141539 rare dwarf shrub Wetland margin 141539 (HBG) rare dwarfshrub / geoxyle geoxylic grassland (sandy soils) 140118 (LUBA) common shrub woodland / forest Myricaceae Morella cf. serrata (Lam.) Killick Myrsinaceae Myrsine africana L. 134107; 134278 (HBG); 139024 (LUBA) Myrtaceae tree woodland / forest 135813 (HBG) Syzygium guineense ssp. macrocarpum (Engl.) F.White common Syzygium guineense ssp. barotsense F.White occasional shrub / tree woodland ecotone 135800; 135796 (HBG) Syzygium guineense ssp. huillense (Hiern) F.White frequent dwarf shrub geoxylic grassland (sandy soils) 133072; 135614; 135882 (HBG) Ochna afzelii ssp. mechowiana R.Br. ex Oliv. rare dwarf shrub / geoxyle woodland / grassland 133128 (HBG) Ochna arenaria De Wild. & T.Durand (Figure 4e) frequent dwarf shrub woodland, geoxylic grassland (sandy and ferralitic soils) 132947; 133024 (HBG); 140016 (LUBA) Ochnaceae Ochna manikensis De Wild. frequent dwarf shrub geoxylic grassland (sandy soils) 132654; 132803 (HBG) Ochna pulchra Hook. common shrub / tree woodland / forest 135381; 139064 (LUBA) Ochna pygmaea Hiern common dwarf shrub / geoxyle woodland / forest, grassland (sandy soils) 139239; 140154 (LUBA) Olacaceae Jasminum pauciflorum Benth. rare liana / shrub woodland / forest 139238 (LUBA) Schrebera trichoclada Welw. rare shrub / tree woodland / forest 139189 (LUBA) rare dwarf shrub woodland / forest 139033 (LUBA) common shrub woodland / forest 135299 (HBG); 139242 (LUBA) rare shrub / tree woodland / forest 139208 (LUBA) occasional tree woodland / forest 133017 (HBG) frequent shrub woodland / forest 135322; 133032 (HBG); 139164 (LUBA) Orobanchaceae Sopubia karaguensis Oliv. Passifloraceae Paropsia brazzaeana Baill. Picodendraceae Oldfieldia dactylophylla (Welw. ex Oliv.) J.Léonard Polygalaceae Securidaca longepedunculata Fresen Polygonaceae Oxygonum fruticosum Dammer ex Milne-Redh. Proteaceae Faurea intermedia Engl. & Gilg occasional shrub / tree woodland / forest 132720; 139072 (LUBA) Faurea rochetiana (A.Rich.) Chiov. ex Pic.Serm. frequent tree woodland / forest / ecotone 135307 (HBG) Faurea saligna Harv. occasional tree geoxylic grassland (ferralitic soils) 132549; 132980; 134205 (HBG) Protea baumii Engl. &Gilg. occasional dwarf shrub woodland / forest 132501; 133019; 134225 (HBG) Protea gaguedi J.F.Gmel. frequent tree woodland / forest 132918 (LUBA) Protea angolensis var. divaricarta (Engl. & Gilg.) Beard rare dwarf shrub geoxylic grassland (ferralitic soils) 134200 (HBG) Protea micans ssp. trichophylla Welw. occasional dwarf shrub geoxylic grassland (sandy soils) 132607 (HBG); 140096 (LUBA) Proteaceae, continued Continued Check List | www.biotaxa.org/cl 7 Volume 13 | Issue 1 | Article 2030 Revermann et al. | Woody species of the Cusseque area, south-central Angola Table 1. Continued. Species name Life form Habitat Collection number(s) Protea petiolaris ssp. petiolaris (Hier) Baker & C.H.Wright frequent Frequency tree woodland / forest 132982 (HBG) Protea cf. welwitschii Engl. rare dwarf shrub geoxylic grassland (ferraliticsoils) 132480 (HBG) Protea sp. 133045 rare dwarf shrub geoxylic grassland (sandy soils) 133045 (HBG) rare shrub woodland / forest 133093; 135285 (HBG) rare dwarf shrub geoxylic grassland (on sandy soils) & woodland ecotone 136003 (HBG) Rhamnaceae Ziziphus mucronata Willd. Rubiaceae Ancylanthos rubiginosus Desf. Fadogia cf. chrysantha K.Schum. very rare shrub woodland ecotone 134257 (HBG) Fadogia cf. triphylla var. triphylla Baker very rare shrub woodland / forest 132987 (HBG); 133081 (HBG) Fadogia fuchsioides Welw. ex Oliv. (Figure 4c) occasional shrub woodland / forest 132524 (HBG) Fadogia cf. homblei De Wild. rare dwarf shrub / geoxyle geoxylic grassland 140114 (LUBA) Fadogia cf. monticola Robyns rare dwarf shrub / geoxyle geoxylic grassland 140146 (LUBA) Fadogia sp. 134097 occasional shrub geoxylic grassland (ferralitic soils), woodland ecotone 132453; 134097; 134167 (HBG) 135338 (HBG) Gardenia brachythamnus (K.Schum.) Launert very rare dwarf shrub woodland ecotone Keetia cf. gracilis (Hiern) Bridson very rare shrub woodland / forest 132442; 133148 (HBG) Keetia venosa (Oliv.) Bridson rare shrub woodland / forest 132534A (HBG) Leptactina benguellensis (Welw. ex Benth. & Hook.f.) R.D.Good rare dwarf shrub woodland / forest 135313; 135353; 133153 (HBG) Leptactina prostrata K.Schum very rare dwarf shrub geoxylic grassland (ferralitic soils) 134181 (HBG) Pachystigma pygmaeum (Schltr.) Robyns frequent dwarf shrub / geoxyle geoxylic grassland (sandy soils) 140138 (LUBA) Pygmaeothamnus cf. chamaedendrum (Kuntze) Robyns very rare dwarf shrub geoxylic grassland (sandy soils) 132723 (HBG) Pygmaeothamnus sp. 132552 dwarf shrub woodland / forest 132552 (HBG) very rare Pygmaeothamnus zeyheri (Sond.) Robyns rare dwarf shrub geoxylic grassland (sandy soils) 132798; 133033; 134089 (HBG) Rytigynia orbicularis (K.Schum.) Robyns frequent shrub woodland / forest 132925; 134127 (HBG); 139056 (LUBA) Tapiphyllum cf. psammophilum (S.Moore) Robyns very rare shrub woodland / forest 134279 (HBG) Tricalysia angolensis A.Rich. ex DC. very rare shrub woodland / forest 132500; 133012 (HBG) Tricalysia sp. 134221 rare shrub woodland / forest 134221 (HBG) Tricalysia coriacea ssp. nyassae (Benth.) Hiern occasional shrub woodland / forest 133008; 134095; 134170 (HBG) Tricalysia sp. 135367 very rare shrub woodland / forest 135367 (HBG) rare dwarf shrub woodland / forest 139228 (LUBA) Santalaceae Thesium sp. 139228 Sapotaceae Chrysophyllum bangweolense R.E.Fr. rare tree woodland / forest 135359 (HBG) Englerophytum magalismontanum (Sond.) T.D.Penn. common shrub woodland / forest 135320 (HBG); 133151 (HBG); 139109 (LUBA) rare shrub woodland / forest 135308A (HBG) Smilacaceae Smilax anceps Willd. Strychnaceae Strychnos cocculoides Baker frequent shrub / tree woodland / forest 139070 (LUBA) Strychnos pungens Soler. common shrub / tree woodland / forest 139254 (LUBA) Strychnos spinosa Lam. occasional tree woodland / forest 135301 (HBG) field work for this study (Gonçalves et al. 2016). In the case of Combretum schumannii Engl. literature indicated that the range of the species might extend to Angola (Exell & Wild 1960). However, neither this taxon nor its synonyms were included in the Angolan checklist (Figueiredo & Smith 2008). Most of the species occurred either in the geoxylic grasslands or in the woodlands and forests. However, many of the geoxylic suffrutices have closely related tree species growing nearby in the woodlands (Figures 4h and 4i). In Africa, the centre of diversity of geoxylic suffrutices is in the Zambezian phytoregion. In regions with similar environmental Check List | www.biotaxa.org/cl conditions, such as the Sudanian phytoregion, there is only a very limited number of geoxylic species (White 1976). We found two types of geoxylic grasslands, each harbouring a very distinct species pool with only a small overlap. There is much debate on the environmental factors driving the emergence of this distinct life form (Davy 1922; White 1976; Maurin et al. 2014; Finckh et al. 2016). However, the different species composition of the two types of geoxylic grasslands found in Cusseque can be clearly attributed to the contrasting edaphic conditions. The two dominant species in the “geoxylic grasslands on ferralitic soils” Cryptosepalum maraviense (Figure 4g) and C. exfoliatum ssp. suffruticans 8 Volume 13 | Issue 1 | Article 2030 Revermann et al. | Woody species of the Cusseque area, south-central Angola Figure 4 Typical plants of the Cusseque area: a) Copaifera baumiana, b) Uvaria angolensis, c) Fadogia fuchsioides, d) Warneckea sapinii, e) Ochna arenaria, f) Combretum platypetalum ssp. platypetalum, g) Cryptosepalum maraviense, h) Cryptoseplaum exfoliatum ssp. suffruticans, i) Cryptosepalum exfoliatum ssp. pseudotaxus. (Figure 4i) belong to the Fabaceae. In contrast, the “geoxylic grasslands on sandy soils” were dominated by various species of the genus Ochna of the Ochnaceae and Parinari capensis of the Chrysobalanaceae. The “geoxylic grasslands on ferralitic soils” have their core distribution on the Angolan Central Plateau and make up 8.5% of the land surface within the Cubango Basin (Revermann et al. in revision). The “geoxylic grasslands on sandy soils” have a very limited distribution within the study site and cover 0.7% of the area of the Cubango Basin. However, they are more extensive further east in the Cuito River Basin and in eastern Moxico Province, where they occur on large sandy, alluvial plains of the Zambezi Graben, e.g., in Cameia National Park. LItEraturE CItED Barbosa, L.A.G. 1970. Carta fitogeográfica de Angola. Luanda: Instituto de Investigação Científica de Angola. 323 pp. Barbosa, L.A.G. 1971. Phytogeographical map of Angola. Mitteilungen der Botanischen Staatssammlung München 10: 114–115. http://biodiversitylibrary.org/page/15185175 Davy, B.J. 1922. The suffrutescent habit as an adaptation to environment. Journal of Ecology 10: 211–219. http://www.jstor.org/ stable/2255742 Dengler, J. 2009. A flexible multi-scale approach for standardised recording of plant species richness patterns. Ecological Indicators 9: 1169–1178. doi: 10.1016/j.ecolind.2009.02.002 Exell, A.W. & Fernandes, A. 1962. Conspectus Florae Angolensis. Lisbon: Junta de Investigações do Ultramar. Vol. 3, Fasc. 1: 1–187. Exell, A.W. & A. Fernandes. 1966. Conspectus Florae Angolensis. Lisbon: Junta de Investigações do Ultramar. Vol. 3, Fasc. 2: 189–408. Exell, A.W., A. Fernandes & E.J. Mendes. 1970. Conspectus Florae Angolensis. Lisbon: Junta de Investigações do Ultramar and Instituto de Investigação Científica de Angola. Vol. 4: 401 pp. Exell, A.W. & F.A. Mendonça. 1937b. Conspectus Florae Angolensis. Lisbon: Junta de Investigações Colonias. Vol. 1, Fasc. 1: 1–176. Exell, A.W. & F.A. Mendonça. 1951. Conspectus Florae Angolensis. Lisbon: Junta de Investigações do Ultramar. Vol. 1, Fasc. 2: 177–422. Exell, A.W. & F.A. Mendonça. 1954. Conspectus Florae Angolensis. Lisbon: Junta de Investigações do Ultramar. Vol. 2, Fasc. 1: 1–152. Exell, A.W. & F.A. Mendonça. 1955. Conspectus Florae Angolensis. aCKNOWLEDGEmENtS Research was funded by the German Federal Ministry of Education and Research (BMBF) in the context of The Future Okavango (TFO) project, grant number 01LL0912A. We are grateful for the support of the staff at Kew Royal Botanical gardens who aided in the identification, in particular David J. Goyder and Iain Darbyshire. Furthermore, we thank the people of the villages Kaololo, Sovi, Cusseque and Calomba and especially the traditional authorities (Sobas) for their support of our study. Check List | www.biotaxa.org/cl 9 Volume 13 | Issue 1 | Article 2030 Revermann et al. | Woody species of the Cusseque area, south-central Angola ommendations for action. Research project final synthesis report 2010–2015. Hamburg: Universtiy of Hamburg, Biocentre Klein Flottbek. 190 pp. R Development Core Team. 2016. R: A language and environment for statistical computing. https://www.R-project.org/ Revermann, R. 2016. Analysis of vegetation and plant diversity patterns in the Okavango basin at different spatial scales — integration of field based methods, remote sensing information and ecological modelling [Dissertation]. Hamburg: University of Hamburg. 295 pp. http://ediss.sub.uni-hamburg.de/volltexte/2016/8156/pdf/ Dissertation.pdf Revermann, R., A.L. Gomes, F.M. Gonçalves, F. Lages & M. Finckh. 2013. Cusseque — vegetation. Biodiversity and Ecology 5: 59–63. doi: 10.7809/b-e.00247 Revermann, R., A.L. Gomes, F.M. Gonçalves, J. Wallenfang, T. Hoche, et al. 2016. Vegetation database of the Okavango Basin. Phytocoenologia 46: 103–104. doi: 10.1127/phyto/2016/0103 Revermann, R., J. Oldeland, F.M. Gonçalves, J. Luther-Mosebach, A.L. Gomes, et al. [In review]. Dry tropical forests of the Cubango basin in southern Africa — a first classification and assessment of their woody species diversity. Phytocoenologia. Schneibel, A., M. Stellmes, D. Frantz, M. Finckh & R. Revermann. 2013. Cusseque — earth Observation. Biodiversity and Ecology 5: 55–57. doi: 10.7809/b-e.00246 Steudel, T., H. Göhmann, W.-A- Flügel & J. Helmschrot. 2013. Assessment of hydrological dynamics in the upper Okavango River Basins. Biodiversity and Ecology 5: 247–261. doi: 10.7809/ b-e.00279 Victor, J.E., M. Koekemoer, L. Fish, S.J. Smithies & M. Mössmer. 2004. Herbarium essentials: the Southern African Herbarium user manual. Pretoria: SABONET. 93 pp. Weber, T. 2013. Cusseque — climate. Biodiversity and Ecology 5: 45–46. doi: 10.7809/b-e.00243 Wehberg, J. & T. Weinzierl. 2013. Okavango Basin — physicogeographical setting. Biodiversity and Ecology 5: 11–13. doi: 10.7809/ b-e.00236 Welwitsch, F. 1869. Sertum Angolense, sive stirpium quarundam novarum vel minus cognitarum. Transactions of the Linnean Society 27: 1–94. doi: 10.1111/j.1096-3642.1869.tb00202.x White, F. 1976. The underground forests of Africa: a preliminary review. The Gardens’ Bulletin Singapore 11: 57–71. Lisbon: Junta de Investigações do Ultramar. Vol. 2, Fasc. 2: 153–320. Exell, A.W. & H. Wild. 1960. Flora Zambesiaca. Glasgow: University Press Glasgow. 336 pp. Figueiredo, E. & G.F. Smith. 2008. Plants of Angola — Plantas de Angola, Strelitzia. Pretoria: South African National Biodiversity Institute. 279 pp. Figueiredo, E., G.F. Smith & J. César. 2009. The flora of Angola: first record of diversity and endemism. Taxon 58: 233–236. http://www.jstor.org/stable/27756837 Figueiredo, E. & G.F. Smith. 2012. Common names of Angolan plants. Pretoria: Inhlaba Books. 262 pp. Finckh, M., R. Revermann & M.P.M. Aidar. 2016. Climate refugees going underground — a response to Maurin et al. 2014. New Phytologist 209: 904–909. doi: 10.1111/nph.13567 Gonçalves, F.M.P., R. Revermann, A.L. Gomes, M.P.M. Aidar, M. Finckh & N. Jürgens. [Accepted]. Tree species diversity and composition of Miombo woodlands in south-central Angola, a chronosequence of forest recovery after shifting cultivation. International Journal of Forestry Research. Gonçalves, F.M., J.J. Tchamba & D.J. Goyder. 2016. Schistostephium crataegifolium Compositae: Anthemideae, a new generic record. Bothalia — African Biodiversity and Conservation 46: a209. doi: 10.4102/abc.v46i1.202 9 Gossweiler, J. & F.A. Mendonça. 1939. Carta fitogeográphica de Angola. Lisbon: República Portuguesa Ministério das Colónias. 242 pp. Gröngröft, A., J. Luther-Mosebach, L. Landschreiber & A. Eschenbach. 2013a. Cusseque — soils. Biodiversity and Ecology 5: 51–54. doi: 10.7809/b-e.00245 Gröngröft, A., J. Luther-Mosebach, L. Landschreiber, R. Revermann, M. Finckh & A. Eschenbach. 2013b. Cusseque — landscape. Biodiversity and Ecology 5: 43–44. doi: 10.7809/b-e.00242 Huntley, B.J. & P. Coelho. 2011. Avaliação Rápida Da Biodiversidade Da Região Da Lagoa de Carumbo/Rapid Biodiversity Assessment of the Carumbo Lagoon Area. Luanda: Ministério do ambiente, República de Angola. 219 pp. Kissanga Vicente da Silva Firmino, R. 2016. Valorização da flora de Cusseque e Caiúndo no centro e sul de Angola e avaliação da biomassa lenhosa utilizada para combustível e construção [Master’s thesis]. Lisbon: University of Lisbon. 63 pp. Mannheimer, C. & B.A. Curtis. 2009. Trees and shrubs of Namibia. Windhoek: Macmillan Education Namibia. 526 pp. Maurin, O., T.J. Davies, J.E. Burrows, B.H. Daru, K. Yessoufou, et al. 2014. Savanna fire and the origins of the ‘underground forests’ of Africa. New Phytologist 204: 201–214. doi: 10.1111/nph.12936 Monteiro, R.F.R. 1970. Estudo da flora e da vegetação das florestas abertas do plantalto do Bié. Luanda: Instituto de Investigação Científica de Angola. 352 pp. Pröpper, M., A. Gröngröft, M. Finckh, S. Stirn, V. De Cauwer, et al. 2015. The Future Okavango — findings, scenarios and rec- Check List | www.biotaxa.org/cl authors’ contributions: All authors contributed to the manuscript, carried out fieldwork and worked on the identification of the collected specimens. RR wrote the initial draft of the manuscript, analysed the data and compiled the figures and tables. received: 19 December 2015 accepted: 7 December 2016 academic editor: Alexander Zizka 10 Volume 13 | Issue 1 | Article 2030 Check List the journal of biodiversity data Check List 13(1): 2030, 6 January 2017 doi: https://doi.org/10.15560/13.1.2030 ISSN 1809-127X © 2017 Check List and Authors LISTS OF SPECIES Woody species of the Miombo woodlands and geoxylic grasslands of the Cusseque area, south-central Angola Rasmus Revermann1, 4, Francisco Maiato Gonçalves1, 2, Amândio Luis Gomes1, 3 & Manfred Finckh1 1 University of Hamburg, Biocentre Klein Flottbek, Department of Biodiversity, Ecology and Evolution of Plants, Ohnhorststr. 18, 22609 Hamburg, Germany 2 Herbarium of Lubango, ISCED-Huíla, Department of Natural Sciences, Rua Sarmento Rodrigues, 230 Lubango, Angola 3 University Agostinho Neto, Faculty of Sciences, Department of Biology, Av. 4 de Fevereiro, Luanda, Angola 4 Corresponding author. E-mail: rasmus.revermann@uni-hamburg.de types and over 100 subordinate types dealt with in the text (Barbosa 1970, 1971). However, the descriptions of these vegetation types were of general character and limited to the dominant species. Detailed descriptions of the species composition and plant diversity of the Angolan vegetation are lacking for most parts of the country. For the province of Bié, Monteiro (1970) provided an excellent overview on the woody vegetation including the first provincial map of the woodlands. Based on 144 relevés, Monteiro delineated three associations of woody plants and four sub-associations. The civil war that followed Angola’s independence in 1975 made any scientific work in Angola extremely difficult, and thus, most scientific literature available today dates back to the pre-independence era. Since the end of the armed conflict in 2002, scientific work is slowly increasing. However, botanical work in the country is still hampered by the lack of field guides and the fact that the principal work on the flora of Angola, the Conspectus Florae Angolensis, remains unfinished and important families such as the Rubiaceae are not treated. Similarly, a countrywide checklist of the flora of Angola was lacking until the recent publication of “Plants of Angola – Plantas de Angola” by Figueiredo & Smith (2008). Nevertheless, inventories of vascular plants at the local and regional scale are still lacking for most parts of the country. Such inventories are indispensable for any kind of natural resource management planning, conservation measures or ecological studies (Figueiredo et al. 2009). The interdisciplinary research project “The Future Okavango” (TFO) aims to provide a scientific basis for strategic resource planning for the Okavango Basin. The headwaters of the Okavango River, where 95% of the runoff are generated, are located on the Angolan Central Plateau (Steudel et al. 2013). Rapid transformations of the social-ecological systems are currently taking place there (Pröpper et al. 2015). However, little knowledge abstract: The species composition of the vegetation in most regions of Angola has been poorly studied and most studies date back to the pre-independence era. In this study, we provide a detailed account of the woody flora of the Miombo woodlands and geoxylic grasslands of the Cusseque study site of “The Future Okavango” (TFO) project, situated on the Angolan Central Plateau. The checklist is based on a vegetation survey using vegetation plots of 1,000 m2 and also includes records from botanical collections made elsewhere at the study site. In total, we documented 154 woody species belonging to 99 genera of 37 plant families in 100 km2. The study represents the first comprehensive account of the woody vegetation of the area including all habitats and growth forms. Key words: Angola; Bié; geoxylic suffrutex; Miombo; The Future Okavango project; vegetation survey INtrODuCtION Rural communities in Angola hold an enormous knowledge of the local flora and especially have great understanding of the potential usages of plants (Figueiredo & Smith 2012; Kissanga 2016). In contrast, scientific exploration and documentation of the vegetation of Angola is still limited. Early botanists such as Friedrich Welwitsch visited the country in the middle of the 19th century (Welwitsch 1869). The most influential botanist working in Angola in the first half of the 20th century was John Gossweiler, who worked in all Angolan provinces and collected over 14,000 specimens. His collection is considered an especially important source of information for rare and endemic species (Figueiredo & Smith 2008). Furthermore, Gossweiler produced the first phytogeographic map of Angola containing 19 principal vegetation types (Gossweiler & Mendonça 1939). Based on this map and his own observations, Luís A. Grandvaux Barbosa published a new phytogeographic map in 1971 containing 32 main 1 Revermann et al. | Woody species of the Cusseque area, south-central Angola season lasting from November to April. The mean annual precipitation is 987 mm and the mean annual temperature is 20.4°C (Weber 2013). The study area harbours a high pedodiversity. The elevated areas are characterized by deep and developed slightly loamy Arenosols. The slopes of the smaller valleys of the tributaries and at the western side of the Cusseque River show shallow Plinthisols on granitic bedrock. The soils along the eastern part of the Cusseque River are characterized by very deep and leached Arenosols. The centre of the valleys support Histosols with peat layers exceeding 1 m in depth while at the edges of the wetlands Gleysols are the common soil type (Gröngröft et al. 2013a). The main vegetation types covering south central Angola are semi-deciduous Miombo woodlands and forests (Figures 2a and b). These woodlands are interspersed with open vegetation types locally termed anharas de ongote. The salient feature of the open vegetation types are dwarf shrubs with a huge underground woody biomass. This distinct life form was described by White (1976) as “geoxylic suffrutex”. In the Cusseque area, geoxylic suffrutices occur on two different soil types: on deep, leached sandy soils and on shallow, compact, ferralitic soils. Accordingly, we will differentiate herein between “geoxylic grasslands on sandy soils” (Figure 2c) and “geoxylic grasslands on ferralitic soils” (Figure 2d). The occurrences of the different vegetation types are governed by topography: woodlands and forests are confined to the elevated areas and upper slopes. The mid- and lower and data on the vegetation and the botanical diversity was available (Revermann 2016). In this study, we present results of the vegetation survey carried out at the research site “Cusseque” in the province of Bié located at the upper reaches of the Okavango River. matErIaLS aND mEtHODS Study site The Okavango River originates on the Angolan Central Plateau and terminates in a large inland delta in the Kalahari Desert in Botswana. Within the TFO project, detailed studies were carried out at four research sites representing the different parts of the river basin. The work presented in this paper was carried out at the study site Cusseque with an area of 100 km2 (13.6985° S, 017.0382° E). The site is located on the Angolan Central Plateau in the province of Bié (Figure 1; Wehberg & Weinzierl 2013). The landscape can be described as a rolling plain intersected by the Cusseque River and its many tributaries, which are orientated perpendicular to each other. Three major landscape units can be identified: the elevated areas, the sloping areas leading down to the valley bottoms and the valley floors (Gröngröft et al. 2013b). The mean elevation is 1,575 m above sea level while the difference in elevation between the valley bottom of the main river and the surrounding elevated areas is about 100 m (Gröngröft et al. 2013b). The climate of the Cusseque area is semi-humid with a pronounced wet Figure 1. Location of the Okavango Basin in southern Africa and the study site “Cusseque” denoted in red. (Projection: WGS 1984; background: RapidEye high-resolution satellite imagery, recorded 1 May 2013. We acknowledge the DLR for the provision of the data from the RapidEye Science Archive.) Check List | www.biotaxa.org/cl 2 Volume 13 | Issue 1 | Article 2030 Revermann et al. | Woody species of the Cusseque area, south-central Angola Figure 2. Landscapes of the Cusseque study area: a) Miombo woodland in the middle of the rainy season, b) Miombo woodland at the end of the rainy season, c) geoxylic grasslands dominated by Cryptosepalum maraviense at the beginning of the rainy season in October, d) geoxylic grassland on sandy soils at the beginning of the dry season in May; in the background wetland on the valley bottom and Miombo woodlands. slopes feature geoxylic grasslands. The woodlands and geoxylic grasslands are separated by ecotones extending up to several hundred meters where elements of both vegetation types co-occur. The valley bottoms support wetlands dominated by Cyperaceae (Revermann et al. 2013; Schneibel et al. 2013). to the unique character of the geoxylic grasslands, these were subject to an additional field study. Therein, data were collected using 10 m × 10 m plots with two 3.3 m × 3.3 m subplots situated in diagonally opposite corners (adapted from Dengler 2009). In every plot all vascular plants found were recorded and their projected cover estimated visually. Unknown plants were photographed and voucher specimens were collected according to botanical methods outlined by Victor et al. (2004). Voucher specimens were deposited in the herbarium of the ISCED Huíla (LUBA) and in the Herbarium Hamburgense (HBG). In addition to the species recorded on the vegetation plots, species found elsewhere while working at the study area were added to the checklist. A high number of vegetation plots and several months of field work carried out by four observers in all seasons ensured a comprehensive coverage of the woody species present at the study area. Data collection Plot based vegetation surveys were carried out during the growing season in the years 2011 to 2014 and all information is stored in the Vegetation Database of the Okavango Basin (GIVD ID: AF-00-009, Revermann et al. 2016). In order to evenly map all existing vegetation units, sampling followed a random, stratified design. Based on an image segmentation algorithm using all bands of a Landsat 7 scene, seven major vegetation units were identified. In these vegetation units random points were created using GIS and transferred to a hand-held GPS for localization in the field. Furthermore, additional vegetation plots were examined in different successional stages of Miombo forest to analyse successional pathways of the regeneration of natural vegetation after disturbance by shifting cultivation (Gonçalves et al., accepted). We used a nested plot design with a 10 m × 10 m plot located in the centre of a 20 m × 50 m plot. In total, we sampled 148 vegetation plots. Due Check List | www.biotaxa.org/cl taxonomy and plant identification We followed the taxonomy of the checklist “Plants of Angola – Plantas de Angola” by Figueiredo & Smith (2008). We are aware of recent changes in the taxonomy, but decided to conform to the national checklist. For identification, we consulted the Conspectus Florae Angolensis (Exell & Mendonça 1937, 1951, 1954, 1955; Exell & Fernandes 3 Volume 13 | Issue 1 | Article 2030 Revermann et al. | Woody species of the Cusseque area, south-central Angola 1962, 1966; Exell et al. 1970) when possible, and the flora of neighbouring countries, especially the Flora Zambeziaca (Exell & Wild 1960) and the field guide to the Trees and shrubs of Namibia (Mannheimer & Curtis 2009). Additionally, we consulted herbarium collections at the ISCED Huíla (LUBA) and the Instituto de Investigação Científica Tropical (LISC) as well as the on-line database JSTOR Plant Science (http://plants.jstor.org/). For some specimens, we consulted experts at Kew Botanical Garden (K). Permits Permits for plant collection and transfer of biological material in Angola for scientific purposes was arranged based on the framework of Material Transfer Agreements from Angola, negotiated between the Instituto Superior de Ciências de Educação da Huíla (ISCED, Huíla), Lubango and the University of Hamburg (UHH), Germany and authorized on behalf of the Angolan Government by the Director for Agriculture, Fisheries and Environment of the Province of Huíla. All International Conventions to which Angola is signatory country, such as Convention on International Trade in Endangered Species of Wild Fauna and Flora (1973), Convention on Biological Diversity (1992), International Treaty on Plant Genetic Resources for Food and Agriculture (2004), and all other relevant national and international instruments concerning biodiversity were taken into account. Figure 3. The families of woody plants found at the Cusseque study site, south-central Angola. Only families with more than two species are shown. In total 37 families of woody plant species occurred, containing 154 species in 99 genera. and forests showed the highest woody species richness with 110 species belonging to 32 families. A surprisingly high number of 33 woody species from 14 families were found in the geoxylic grasslands. These open vegetation types appear to be merely grasslands in the late growing season (Figures 2c and d) but in fact harbour a remarkable diversity of woody species (Table 1). In the wetlands few woody species occurred and we recorded only two Ficus species sporadically occurring along the margins of the wetlands. One species, Combretum schumannii Engl., was recorded but is not listed in the current checklist of Angola (Figueiredo & Smith 2008). Data analysis DISCuSSION We visualized the number of species per family of all species belonging to one family using the function ‘pie’ in the statistical software R (R Development Core Team 2016). Data on the frequency of occurrence of a species, the habitat and the life form were compiled from vegetation plot data. We assigned frequency according to the following categories: very rare (1 or 2 observations), rare (3–5 observations), occasional (6–10 observations), frequent (11–30 observations), common (>30 observations). We assigned every species to one or more of the following life form categories based on field observations and literature: tree, shrub, liana, dwarf shrub and geoxyle. For geoxyles we followed the definition proposed by White (1976). White defined a geoxyle as a dwarf shrub that has closely related species growing as trees and that exhibits massive woody underground parts. The 154 species recorded within the 100 km2 of the Cusseque study site almost equalled the 166 woody species found by Monteiro (1970) in the entire province of Bié, an area of 70,314 km2. This does not reflect the quality of the study of Monteiro but rather illustrates how poorly the region has been surveyed so far. In fact, the study carried out by Monteiro (1970) is of high quality and stands out as the only study of its time from Angola basing its analysis on quantitative, plot based data. However, the study was restricted to woodlands and only larger shrubs and trees were included. In contrast, we included all vegetation types ranging from woodlands to geoxylic grasslands and wetlands. Due to the high sampling intensity and the coverage of all vegetation types our species list can therefore be considered a comprehensive checklist of the woody plant species of the Cusseque area. However, it must be noted that this list does not contain any specimen that could not be identified to at least genus level; some specimens were lacking fruits or flowers, preventing further identification. Therefore, the actual number of woody species may be slightly higher. Despite the relatively recent publication of the checklist of vascular plants of Angola, subsequent field surveys in various parts of the country have resulted in additions to the checklist (Huntley & Coelho 2011). We provided the first record in Angola of the herbaceous Asteraceae Schistostephium crataegifolium (DC.) Fenzl ex Harv, during the rESuLtS We documented 154 woody species belonging to 99 genera and 37 families (Table 1). The majority of species belonged to the family Fabaceae (33), followed by Rubiaceae (22), Euphorbiaceae (11), Proteaceae (10) and Combretaceae (9) (Figure 3). Most of the dominant species belonged to the Fabaceae and occurred with high frequencies. In contrast, the Rubiaceae, second in species richness, contained species occurring with low frequencies and were less abundant. The woodlands Check List | www.biotaxa.org/cl 4 Volume 13 | Issue 1 | Article 2030 Revermann et al. | Woody species of the Cusseque area, south-central Angola Table 1. List of species arranged by family. Voucher specimens have been deposited in the herbaria of Lubango (LUBA) and Hamburg (HBG). In most cases doublets are stored in both herbaria. The herbarium name in parentheses is the location where the specimen used for identification is deposited. Frequency was assigned according to the following categories: very rare (1 or 2 observations), rare (3–5 observations), occasional (6–10 observations), frequent (11–30 observations), common (>30 observations). Life forms of the species were assigned to one or more of the categories: tree, shrub, liana, dwarf shrub and geoxyle. Species name Frequency Life form Habitat Collection number(s) Anacardiaceae Ozoroa cf. xylophylla (Engl. &Gilg) R.Fern. & A.Fern. very rare shrub geoxylic grassland (sandy soils) 133057B (HBG) Ozoroa stenophylla Engl. & Gilg. frequent shrub woodland / grassland (ferralitic soils) 140123 (LUBA) Rhus arenaria Torre, A.R. frequent dwarf shrub / geoxyle geoxylic grassland (ferralitic soils) 140101 (LUBA) Rhus exelliana Meikle frequent dwarf shrub Rhus gracilipes Exell frequent dwarf shrub woodland / forest 139227; 132483 (HBG) 135250; 134275 (HBG) Rhus kirkii Oliv. frequent dwarf shrub woodland / forest 139253 (LUBA) Anisophylleaceae Anisophyllea boehmii Engl. frequent tree woodland / forest 134316; 139018; 135297 (HBG) Anisophyllea quangensis Engl. ex Henriq. rare dwarf shrub geoxylic grassland (sandy soils) 133044; 134116 (HBG); 140109 (LUBA) Annoncaceae Annona stenophylla ssp. nana Engl. & Diels rare dwarf shrub woodland / forest 133058; 134218 (HBG); 140065 (LUBA) Uvaria angolensis Welw. ex Oliv. (Figure 4b) frequent shrub woodland / forest 135323; 134240 (HBG) Xylopia odoratissima Welw. ex Oiv. frequent shrub woodland / forest 133057A; 134263 (HBG) Xylopia tomentosa Exell common shrub woodland / forest 135279; 132956; 132986 (HBG); 139177 (LUBA) common dwarf shrub / geoxyle geoxylic grassland (sandy soils) 140121 (LUBA) Apocynaceae Chamaeclitandra henriquesiana (Hallier f.) Pichon Diplorhynchus condylocarpon (Müll. Arg.) Pichon frequent shrub / tree woodland / forest 135300 (HBG) Landolphia camptoloba (K.Schum.) Pichon frequent liana woodland / forest 132537 (HBG) Landolphia gossweileri (Stapf ) Pichon rare dwarf shrub geoxylic grassland (sandy soils) 133048 (HBG) Strophanthus welwitschii (Baill.) K.Schum. frequent liana woodland / forest 135336; 135378; 134091 (HBG) Asparagaceae Asparagus sp. 135286 frequent shrub woodland / forest 135286 (HBG) Asparagus cf. africanus Lam. very rare shrub woodland / forest 134115 (HBG) occasional shrub woodland / forest 132695 (HBG) Parinari capensis Harv. frequent dwarf shrub / geoxyle geoxylic grassland (sandy soils) 132664; 132898; 140068 (HBG) Parinari curatellifolia Planch. ex Benth. common tree woodland / forest 132444 (HBG) Asteraceae Helichrysum krausii Sch. Bip Crysobalanaceae Combretaceae Combretum acutifolium Exell very rare liana / shrub woodland / forest 135306 (HBG) Combretum collinum Fresen. common tree woodland / forest 139176 (HBG) Combretum elaeagnoides Klotzsch very rare tree woodland / forest 132538 (HBG) Combretum engleri Schinz frequent shrub woodland / forest 133216 (HBG) Combretum platypetalum ssp. platypetalum Welw. ex M.A.Lawson (Figure 4f ) occasional dwarf shrub geoxylic grassland (sandy soils) 132639; 134114; 140113 (HBG) Combretum schumannii Engl. rare shrub woodland / forest 139048 (LUBA) Combretum zeyheri Sond. frequent shrub / tree woodland / forest 135280; 132510 (HBG) Pteleopsis anisoptera (Welw.) Engl. & Diels frequent shrub / tree woodland / forest 135365; 134110 (HBG); 139066 (LUBA) Terminalia brachystemma Welw. ex Hiern frequent tree woodland / forest / grassland (sandy and ferralitic soils) 132997; 134088; 134131 (HBG) frequent dwarf shrub / geoxyle geoxylic grassland (sandy soils) 140165 (LUBA) Dichapetalaceae Dichapetalum cymosum (Hook.) Engl. Dipterocarpaceae Monotes africanus A.DC. common tree woodland / forest 132917; 134160; 134228 (HBG) Monotes angolensis de Wild. very rare tree woodland / forest 132443 (HBG) Monotes caloneurus Gilg. rare tree woodland / forest 134820 (HBG) Monotes dasyanthus Gilg common tree woodland / forest 132907; 132961 (HBG); 139228 (LUBA) Ebenaceae Diospyros batocana Hiern occasional shrub / tree woodland / forest 139247 (LUBA) Diospyros chamaethamnus Dinter ex Mildbr. frequent dwarf shrub / geoxyle geoxylic grassland (sandy soils) 140179 (LUBA) Continued Check List | www.biotaxa.org/cl 5 Volume 13 | Issue 1 | Article 2030 Revermann et al. | Woody species of the Cusseque area, south-central Angola Table 1. Continued. Species name Frequency Life form Habitat Collection number(s) Ebenaceae, continued Diospyros pseudomespilus ssp. brevicalyx Mildbr. Diospyros virgata (Gürke) Brenan Euclea crispa ssp. crispa (Thunb.) Gürke frequent occasional frequent shrub shrub dwarf shrub woodland / forest woodland / forest woodland / forest / geoxylic grassland 135379 (HBG) 132941 (HBG) 135413 (HBG) very rare shrub / tree woodland / forest 139235 (LUBA) occasional frequent rare rare common common occasional frequent common shrub / tree shrub / tree shrub / tree dwarf shrub dwarf shrub dwarf shrub tree dwarf shrub dwarf shrub / geoxyle tree tree woodland / forest woodland / forest woodland / forest woodland / forest woodland / forest woodland / forest woodland / forest woodland / forest geoxylic grassland (ferralitic soils) woodland / forest woodland / forest 139095 (LUBA) 134099; 134135 (HBG); 139068 (LUBA) 139113 (LUBA) 139256 (LUBA) 139238 (LUBA) 139237 (LUBA) 132555; 134232 (HBG); 139038 (LUBA) 132990; 134185 (HBG) 132490; 134199 (HBG) 132691; 132912; 132998 (HBG) geoxylic grassland (sandy soils) 140167 (LUBA) frequent occasional frequent common frequent dwarf shrub / geoxyle tree shrub / tree shrub / tree shrub shrub / tree woodland / forest woodland / forest woodland / forest woodland / forest woodland / forest 134156; 135318 (HBG); 139223 (LUBA) 139065; 135342; 132967 (HBG) 135360; 139242; 133018 (HBG) 135311 (HBG) 132963; 139128 (LUBA) common occasional common common common rare rare rare common tree tree tree tree shrub dwarf shrub dwarf shrub dwarf shrub tree woodland / forest woodland / forest woodland / forest woodland / forest woodland / forest woodland / forest woodland / forest woodland / forest woodland / forest 135298; 139016 (LUBA) 132957; 139255 (LUBA) 132676 (HBG) 132900; 135335 (HBG); 139233 (LUBA) 139121 (LUBA) 139257 (LUBA) 139196 (LUBA) 135304 (HBG); 139023 (LUBA) common dwarf shrub 132754; 132825 (HBG) common dwarf shrub Dalbergia nitidula Welw. ex Baker Dialium englerianum Henriq. Dolichos sp. 140088 rare frequent frequent Entada arenaria Schinz Eriosema sp. 133109 very rare rare shrub / tree shrub / tree dwarf shrub / geoxyle dwarf shrub dwarf shrub Eriosema sp. 132895 rare dwarf shrub Erythrina abyssinica Lam. ex DC. Erythrophleum africanum (Welw. ex Benth.) Harms Guibourtia coleosperma (Benth.) J.Léonard Humularia welwitschii (Taub.) P.A.Duvign. Indigofera baumiana Harms Indigofera congesta Welw. ex Baker Kotschya strobilantha (Welw. ex Baker) Dewit & P. A. Duvign. var. strobilantha Mucuna sp. 140052 very rare common occasional common frequent occasional rare 140052 (LUBA) Pericopsis angolensis (Baker) Meeuwen Pterocarpus angolensis DC frequent occasional tree tree tree dwarf shrub shrub dwarf shrub dwarf shrub / geoxyle dwarf shrub / geoxyle shrub / tree tree geoxylic grassland (ferralitic soils) geoxylic grassland (ferralitic soils) woodland / forest woodland / forest geoxylic grassland (ferralitic soils) geoxylic grassland (sandy soils) geoxylic grassland (ferralitic soils) geoxylic grassland (ferralitic soils) giant termite mounds woodland / forest woodland / forest woodland / forest woodland / forest woodland / forest geoxylic grassland (ferralitic soils) geoxylic grassland (sandy soils) woodland / forest woodland / forest 139181 (LUBA) - Ericaceae Erica benguellensis (Welw. ex Engl.) E.G.H. Oliv. Euphorbiaceae Bridelia sp. 139095 Hymenocardia acida Tul. Maprounea africana Müll. Arg. Phyllanthus angolensis Müll. Arg. Phyllanthus sp. 139238 Phyllanthus welwitschianus Müll. Arg. Pseudolachnostylis maprouneifolia Pax Sclerocroton oblongifolius (Müll. Arg.) Kruijt & Roebers Uapaca sp. 134199 Uapaca kirkiana Müll. Arg. Uapaca nitida var. nitida Müll. Arg. Fabaceae Abrus melanospermus ssp. suffruticosus (Boutique) D.K.Harder Albizia antunesiana Harms Albizia gummifera (J.F.Gmel) C.A.Sm. Baphia bequaertii De Wild. Bauhinia petersiana Bolle Bobgunnia madagascariensis (Desv.) J.H.Kirkbr. & Wiersema Brachystegia bakeriana Hutch. & Burtt Davy Brachystegia longifolia Benth. Brachystegia spiciformis Benth. Burkea africana Hook. Copaifera baumiana Harms Crotalaria amoena Welw. ex Baker Crotalaria cistoides Welw. ex Baker Crotalaria florida Welw. ex Baker Cryptosepalum exfoliatum ssp. pseudotaxus (Baker f.) P.A.Duvign. & Brenan (Figure 4i) Cryptosepalum exfoliatum ssp. suffruticans (P.A.Duvign.) P.A.Duvign. & Bre (Figure 4h) Cryptosepalum maraviense Oliv. (Figure 4g) common common occasional frequent 135308B; 135620 (HBG) 139236 (LUBA) 133147; 139034 (LUBA) 140088 (LUBA) 134147 (HBG) 133109 (HBG) 132753; 132895 (HBG) 135333 (HBG) 139054 (LUBA) 139146 (LUBA) 132530 (HBG) 139237 (LUBA) 139141 (LUBA) Continued Check List | www.biotaxa.org/cl 6 Volume 13 | Issue 1 | Article 2030 Revermann et al. | Woody species of the Cusseque area, south-central Angola Table 1. Continued. Species name Frequency Life form Habitat Collection number(s) Hypericaceae Psorospermum febrifugum Spach. rare shrub / tree woodland / forest 139036 (LUBA) Psorospermum tenuifolium Hook.f. rare shrub / tree woodland / forest 132958 (HBG) common shrub woodland / forest 132968; 133005; 133149 (HBG) Ixonanthaceae Phyllocosmus lemaireanus (De Wild. & T.Durand) T.Durand & H.Durand Lamicaceae Alvesia rosmarinifolia Welw. occasional shrub woodland / forest 134776; 132533 (HBG) Tinnea sp. 133121 frequent dwarf shrub geoxylic grassland (ferralitic soils) 133121 (HBG) Vitex doniana Sweet occasional shrub woodland / woodland ecotone 132915 (HBG) Vitex madiensis Oliv. frequent shrub woodland / woodland ecotone 132996 (HBG); 139069 (LUBA) Melastomataceae Memecylon flavovirens Baker frequent shrub / tree woodland / forest 132519; 133161 (HBG); 139240 (LUBA) Warneckea sapinii (De Wild.) Jacq.-Fél. (Figure 4d) occasional tree woodland / forest 135309 (HBG); 139140 (LUBA) occasional shrub woodland / forest 132546; 133000; 133096 (HBG) Meliaceae Ekebergia benguelensis Welw. ex C.DC. Moraceae Ficus pygmaea Welw. ex Hiern rare dwarf shrub wetland margin 141510 (HBG) Ficus sp. 141539 rare dwarf shrub Wetland margin 141539 (HBG) rare dwarfshrub / geoxyle geoxylic grassland (sandy soils) 140118 (LUBA) common shrub woodland / forest Myricaceae Morella cf. serrata (Lam.) Killick Myrsinaceae Myrsine africana L. 134107; 134278 (HBG); 139024 (LUBA) Myrtaceae tree woodland / forest 135813 (HBG) Syzygium guineense ssp. macrocarpum (Engl.) F.White common Syzygium guineense ssp. barotsense F.White occasional shrub / tree woodland ecotone 135800; 135796 (HBG) Syzygium guineense ssp. huillense (Hiern) F.White frequent dwarf shrub geoxylic grassland (sandy soils) 133072; 135614; 135882 (HBG) Ochna afzelii ssp. mechowiana R.Br. ex Oliv. rare dwarf shrub / geoxyle woodland / grassland 133128 (HBG) Ochna arenaria De Wild. & T.Durand (Figure 4e) frequent dwarf shrub woodland, geoxylic grassland (sandy and ferralitic soils) 132947; 133024 (HBG); 140016 (LUBA) Ochnaceae Ochna manikensis De Wild. frequent dwarf shrub geoxylic grassland (sandy soils) 132654; 132803 (HBG) Ochna pulchra Hook. common shrub / tree woodland / forest 135381; 139064 (LUBA) Ochna pygmaea Hiern common dwarf shrub / geoxyle woodland / forest, grassland (sandy soils) 139239; 140154 (LUBA) Olacaceae Jasminum pauciflorum Benth. rare liana / shrub woodland / forest 139238 (LUBA) Schrebera trichoclada Welw. rare shrub / tree woodland / forest 139189 (LUBA) rare dwarf shrub woodland / forest 139033 (LUBA) common shrub woodland / forest 135299 (HBG); 139242 (LUBA) rare shrub / tree woodland / forest 139208 (LUBA) occasional tree woodland / forest 133017 (HBG) frequent shrub woodland / forest 135322; 133032 (HBG); 139164 (LUBA) Orobanchaceae Sopubia karaguensis Oliv. Passifloraceae Paropsia brazzaeana Baill. Picodendraceae Oldfieldia dactylophylla (Welw. ex Oliv.) J.Léonard Polygalaceae Securidaca longepedunculata Fresen Polygonaceae Oxygonum fruticosum Dammer ex Milne-Redh. Proteaceae Faurea intermedia Engl. & Gilg occasional shrub / tree woodland / forest 132720; 139072 (LUBA) Faurea rochetiana (A.Rich.) Chiov. ex Pic.Serm. frequent tree woodland / forest / ecotone 135307 (HBG) Faurea saligna Harv. occasional tree geoxylic grassland (ferralitic soils) 132549; 132980; 134205 (HBG) Protea baumii Engl. &Gilg. occasional dwarf shrub woodland / forest 132501; 133019; 134225 (HBG) Protea gaguedi J.F.Gmel. frequent tree woodland / forest 132918 (LUBA) Protea angolensis var. divaricarta (Engl. & Gilg.) Beard rare dwarf shrub geoxylic grassland (ferralitic soils) 134200 (HBG) Protea micans ssp. trichophylla Welw. occasional dwarf shrub geoxylic grassland (sandy soils) 132607 (HBG); 140096 (LUBA) Proteaceae, continued Continued Check List | www.biotaxa.org/cl 7 Volume 13 | Issue 1 | Article 2030 Revermann et al. | Woody species of the Cusseque area, south-central Angola Table 1. Continued. Species name Life form Habitat Collection number(s) Protea petiolaris ssp. petiolaris (Hier) Baker & C.H.Wright frequent Frequency tree woodland / forest 132982 (HBG) Protea cf. welwitschii Engl. rare dwarf shrub geoxylic grassland (ferraliticsoils) 132480 (HBG) Protea sp. 133045 rare dwarf shrub geoxylic grassland (sandy soils) 133045 (HBG) rare shrub woodland / forest 133093; 135285 (HBG) rare dwarf shrub geoxylic grassland (on sandy soils) & woodland ecotone 136003 (HBG) Rhamnaceae Ziziphus mucronata Willd. Rubiaceae Ancylanthos rubiginosus Desf. Fadogia cf. chrysantha K.Schum. very rare shrub woodland ecotone 134257 (HBG) Fadogia cf. triphylla var. triphylla Baker very rare shrub woodland / forest 132987 (HBG); 133081 (HBG) Fadogia fuchsioides Welw. ex Oliv. (Figure 4c) occasional shrub woodland / forest 132524 (HBG) Fadogia cf. homblei De Wild. rare dwarf shrub / geoxyle geoxylic grassland 140114 (LUBA) Fadogia cf. monticola Robyns rare dwarf shrub / geoxyle geoxylic grassland 140146 (LUBA) Fadogia sp. 134097 occasional shrub geoxylic grassland (ferralitic soils), woodland ecotone 132453; 134097; 134167 (HBG) 135338 (HBG) Gardenia brachythamnus (K.Schum.) Launert very rare dwarf shrub woodland ecotone Keetia cf. gracilis (Hiern) Bridson very rare shrub woodland / forest 132442; 133148 (HBG) Keetia venosa (Oliv.) Bridson rare shrub woodland / forest 132534A (HBG) Leptactina benguellensis (Welw. ex Benth. & Hook.f.) R.D.Good rare dwarf shrub woodland / forest 135313; 135353; 133153 (HBG) Leptactina prostrata K.Schum very rare dwarf shrub geoxylic grassland (ferralitic soils) 134181 (HBG) Pachystigma pygmaeum (Schltr.) Robyns frequent dwarf shrub / geoxyle geoxylic grassland (sandy soils) 140138 (LUBA) Pygmaeothamnus cf. chamaedendrum (Kuntze) Robyns very rare dwarf shrub geoxylic grassland (sandy soils) 132723 (HBG) Pygmaeothamnus sp. 132552 dwarf shrub woodland / forest 132552 (HBG) very rare Pygmaeothamnus zeyheri (Sond.) Robyns rare dwarf shrub geoxylic grassland (sandy soils) 132798; 133033; 134089 (HBG) Rytigynia orbicularis (K.Schum.) Robyns frequent shrub woodland / forest 132925; 134127 (HBG); 139056 (LUBA) Tapiphyllum cf. psammophilum (S.Moore) Robyns very rare shrub woodland / forest 134279 (HBG) Tricalysia angolensis A.Rich. ex DC. very rare shrub woodland / forest 132500; 133012 (HBG) Tricalysia sp. 134221 rare shrub woodland / forest 134221 (HBG) Tricalysia coriacea ssp. nyassae (Benth.) Hiern occasional shrub woodland / forest 133008; 134095; 134170 (HBG) Tricalysia sp. 135367 very rare shrub woodland / forest 135367 (HBG) rare dwarf shrub woodland / forest 139228 (LUBA) Santalaceae Thesium sp. 139228 Sapotaceae Chrysophyllum bangweolense R.E.Fr. rare tree woodland / forest 135359 (HBG) Englerophytum magalismontanum (Sond.) T.D.Penn. common shrub woodland / forest 135320 (HBG); 133151 (HBG); 139109 (LUBA) rare shrub woodland / forest 135308A (HBG) Smilacaceae Smilax anceps Willd. Strychnaceae Strychnos cocculoides Baker frequent shrub / tree woodland / forest 139070 (LUBA) Strychnos pungens Soler. common shrub / tree woodland / forest 139254 (LUBA) Strychnos spinosa Lam. occasional tree woodland / forest 135301 (HBG) field work for this study (Gonçalves et al. 2016). In the case of Combretum schumannii Engl. literature indicated that the range of the species might extend to Angola (Exell & Wild 1960). However, neither this taxon nor its synonyms were included in the Angolan checklist (Figueiredo & Smith 2008). Most of the species occurred either in the geoxylic grasslands or in the woodlands and forests. However, many of the geoxylic suffrutices have closely related tree species growing nearby in the woodlands (Figures 4h and 4i). In Africa, the centre of diversity of geoxylic suffrutices is in the Zambezian phytoregion. In regions with similar environmental Check List | www.biotaxa.org/cl conditions, such as the Sudanian phytoregion, there is only a very limited number of geoxylic species (White 1976). We found two types of geoxylic grasslands, each harbouring a very distinct species pool with only a small overlap. There is much debate on the environmental factors driving the emergence of this distinct life form (Davy 1922; White 1976; Maurin et al. 2014; Finckh et al. 2016). However, the different species composition of the two types of geoxylic grasslands found in Cusseque can be clearly attributed to the contrasting edaphic conditions. The two dominant species in the “geoxylic grasslands on ferralitic soils” Cryptosepalum maraviense (Figure 4g) and C. exfoliatum ssp. suffruticans 8 Volume 13 | Issue 1 | Article 2030 Revermann et al. | Woody species of the Cusseque area, south-central Angola Figure 4 Typical plants of the Cusseque area: a) Copaifera baumiana, b) Uvaria angolensis, c) Fadogia fuchsioides, d) Warneckea sapinii, e) Ochna arenaria, f) Combretum platypetalum ssp. platypetalum, g) Cryptosepalum maraviense, h) Cryptoseplaum exfoliatum ssp. suffruticans, i) Cryptosepalum exfoliatum ssp. pseudotaxus. (Figure 4i) belong to the Fabaceae. In contrast, the “geoxylic grasslands on sandy soils” were dominated by various species of the genus Ochna of the Ochnaceae and Parinari capensis of the Chrysobalanaceae. The “geoxylic grasslands on ferralitic soils” have their core distribution on the Angolan Central Plateau and make up 8.5% of the land surface within the Cubango Basin (Revermann et al. in revision). The “geoxylic grasslands on sandy soils” have a very limited distribution within the study site and cover 0.7% of the area of the Cubango Basin. However, they are more extensive further east in the Cuito River Basin and in eastern Moxico Province, where they occur on large sandy, alluvial plains of the Zambezi Graben, e.g., in Cameia National Park. LItEraturE CItED Barbosa, L.A.G. 1970. Carta fitogeográfica de Angola. Luanda: Instituto de Investigação Científica de Angola. 323 pp. Barbosa, L.A.G. 1971. Phytogeographical map of Angola. Mitteilungen der Botanischen Staatssammlung München 10: 114–115. http://biodiversitylibrary.org/page/15185175 Davy, B.J. 1922. The suffrutescent habit as an adaptation to environment. Journal of Ecology 10: 211–219. http://www.jstor.org/ stable/2255742 Dengler, J. 2009. A flexible multi-scale approach for standardised recording of plant species richness patterns. Ecological Indicators 9: 1169–1178. doi: 10.1016/j.ecolind.2009.02.002 Exell, A.W. & Fernandes, A. 1962. Conspectus Florae Angolensis. Lisbon: Junta de Investigações do Ultramar. Vol. 3, Fasc. 1: 1–187. Exell, A.W. & A. Fernandes. 1966. Conspectus Florae Angolensis. Lisbon: Junta de Investigações do Ultramar. Vol. 3, Fasc. 2: 189–408. Exell, A.W., A. Fernandes & E.J. Mendes. 1970. Conspectus Florae Angolensis. Lisbon: Junta de Investigações do Ultramar and Instituto de Investigação Científica de Angola. Vol. 4: 401 pp. Exell, A.W. & F.A. Mendonça. 1937b. Conspectus Florae Angolensis. Lisbon: Junta de Investigações Colonias. Vol. 1, Fasc. 1: 1–176. Exell, A.W. & F.A. Mendonça. 1951. Conspectus Florae Angolensis. Lisbon: Junta de Investigações do Ultramar. Vol. 1, Fasc. 2: 177–422. Exell, A.W. & F.A. Mendonça. 1954. Conspectus Florae Angolensis. Lisbon: Junta de Investigações do Ultramar. Vol. 2, Fasc. 1: 1–152. Exell, A.W. & F.A. Mendonça. 1955. Conspectus Florae Angolensis. aCKNOWLEDGEmENtS Research was funded by the German Federal Ministry of Education and Research (BMBF) in the context of The Future Okavango (TFO) project, grant number 01LL0912A. We are grateful for the support of the staff at Kew Royal Botanical gardens who aided in the identification, in particular David J. Goyder and Iain Darbyshire. Furthermore, we thank the people of the villages Kaololo, Sovi, Cusseque and Calomba and especially the traditional authorities (Sobas) for their support of our study. Check List | www.biotaxa.org/cl 9 Volume 13 | Issue 1 | Article 2030 Revermann et al. | Woody species of the Cusseque area, south-central Angola ommendations for action. Research project final synthesis report 2010–2015. Hamburg: Universtiy of Hamburg, Biocentre Klein Flottbek. 190 pp. R Development Core Team. 2016. R: A language and environment for statistical computing. https://www.R-project.org/ Revermann, R. 2016. Analysis of vegetation and plant diversity patterns in the Okavango basin at different spatial scales — integration of field based methods, remote sensing information and ecological modelling [Dissertation]. Hamburg: University of Hamburg. 295 pp. http://ediss.sub.uni-hamburg.de/volltexte/2016/8156/pdf/ Dissertation.pdf Revermann, R., A.L. Gomes, F.M. Gonçalves, F. Lages & M. Finckh. 2013. Cusseque — vegetation. Biodiversity and Ecology 5: 59–63. doi: 10.7809/b-e.00247 Revermann, R., A.L. Gomes, F.M. Gonçalves, J. Wallenfang, T. Hoche, et al. 2016. Vegetation database of the Okavango Basin. Phytocoenologia 46: 103–104. doi: 10.1127/phyto/2016/0103 Revermann, R., J. Oldeland, F.M. Gonçalves, J. Luther-Mosebach, A.L. Gomes, et al. [In review]. Dry tropical forests of the Cubango basin in southern Africa — a first classification and assessment of their woody species diversity. Phytocoenologia. Schneibel, A., M. Stellmes, D. Frantz, M. Finckh & R. Revermann. 2013. Cusseque — earth Observation. Biodiversity and Ecology 5: 55–57. doi: 10.7809/b-e.00246 Steudel, T., H. Göhmann, W.-A- Flügel & J. Helmschrot. 2013. Assessment of hydrological dynamics in the upper Okavango River Basins. Biodiversity and Ecology 5: 247–261. doi: 10.7809/ b-e.00279 Victor, J.E., M. Koekemoer, L. Fish, S.J. Smithies & M. Mössmer. 2004. Herbarium essentials: the Southern African Herbarium user manual. Pretoria: SABONET. 93 pp. Weber, T. 2013. Cusseque — climate. Biodiversity and Ecology 5: 45–46. doi: 10.7809/b-e.00243 Wehberg, J. & T. Weinzierl. 2013. Okavango Basin — physicogeographical setting. Biodiversity and Ecology 5: 11–13. doi: 10.7809/ b-e.00236 Welwitsch, F. 1869. Sertum Angolense, sive stirpium quarundam novarum vel minus cognitarum. Transactions of the Linnean Society 27: 1–94. doi: 10.1111/j.1096-3642.1869.tb00202.x White, F. 1976. The underground forests of Africa: a preliminary review. The Gardens’ Bulletin Singapore 11: 57–71. Lisbon: Junta de Investigações do Ultramar. Vol. 2, Fasc. 2: 153–320. Exell, A.W. & H. Wild. 1960. Flora Zambesiaca. Glasgow: University Press Glasgow. 336 pp. Figueiredo, E. & G.F. Smith. 2008. Plants of Angola — Plantas de Angola, Strelitzia. Pretoria: South African National Biodiversity Institute. 279 pp. Figueiredo, E., G.F. Smith & J. César. 2009. The flora of Angola: first record of diversity and endemism. Taxon 58: 233–236. http://www.jstor.org/stable/27756837 Figueiredo, E. & G.F. Smith. 2012. Common names of Angolan plants. Pretoria: Inhlaba Books. 262 pp. Finckh, M., R. Revermann & M.P.M. Aidar. 2016. Climate refugees going underground — a response to Maurin et al. 2014. New Phytologist 209: 904–909. doi: 10.1111/nph.13567 Gonçalves, F.M.P., R. Revermann, A.L. Gomes, M.P.M. Aidar, M. Finckh & N. Jürgens. [Accepted]. Tree species diversity and composition of Miombo woodlands in south-central Angola, a chronosequence of forest recovery after shifting cultivation. International Journal of Forestry Research. Gonçalves, F.M., J.J. Tchamba & D.J. Goyder. 2016. Schistostephium crataegifolium Compositae: Anthemideae, a new generic record. Bothalia — African Biodiversity and Conservation 46: a209. doi: 10.4102/abc.v46i1.202 9 Gossweiler, J. & F.A. Mendonça. 1939. Carta fitogeográphica de Angola. Lisbon: República Portuguesa Ministério das Colónias. 242 pp. Gröngröft, A., J. Luther-Mosebach, L. Landschreiber & A. Eschenbach. 2013a. Cusseque — soils. Biodiversity and Ecology 5: 51–54. doi: 10.7809/b-e.00245 Gröngröft, A., J. Luther-Mosebach, L. Landschreiber, R. Revermann, M. Finckh & A. Eschenbach. 2013b. Cusseque — landscape. Biodiversity and Ecology 5: 43–44. doi: 10.7809/b-e.00242 Huntley, B.J. & P. Coelho. 2011. Avaliação Rápida Da Biodiversidade Da Região Da Lagoa de Carumbo/Rapid Biodiversity Assessment of the Carumbo Lagoon Area. Luanda: Ministério do ambiente, República de Angola. 219 pp. Kissanga Vicente da Silva Firmino, R. 2016. Valorização da flora de Cusseque e Caiúndo no centro e sul de Angola e avaliação da biomassa lenhosa utilizada para combustível e construção [Master’s thesis]. Lisbon: University of Lisbon. 63 pp. Mannheimer, C. & B.A. Curtis. 2009. Trees and shrubs of Namibia. Windhoek: Macmillan Education Namibia. 526 pp. Maurin, O., T.J. Davies, J.E. Burrows, B.H. Daru, K. Yessoufou, et al. 2014. Savanna fire and the origins of the ‘underground forests’ of Africa. New Phytologist 204: 201–214. doi: 10.1111/nph.12936 Monteiro, R.F.R. 1970. Estudo da flora e da vegetação das florestas abertas do plantalto do Bié. Luanda: Instituto de Investigação Científica de Angola. 352 pp. Pröpper, M., A. Gröngröft, M. Finckh, S. Stirn, V. De Cauwer, et al. 2015. The Future Okavango — findings, scenarios and rec- Check List | www.biotaxa.org/cl authors’ contributions: All authors contributed to the manuscript, carried out fieldwork and worked on the identification of the collected specimens. RR wrote the initial draft of the manuscript, analysed the data and compiled the figures and tables. received: 19 December 2015 accepted: 7 December 2016 academic editor: Alexander Zizka 10 Volume 13 | Issue 1 | Article 2030

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