30 Sunderland et al. Herbaceous flora <strong>of</strong> this forest formation is particularly diverse and <strong>in</strong>cludes Acanthus montanus, Aframomum pilosum, Marantochloa leucantha, Halopegia azurea, Nephthytis poisonii, Mapania amplivag<strong>in</strong>ata, Impatiens kamerunensis var. kamerunensis, and Osmunda regalis, with many species <strong>of</strong> Begonia (Begonia capillipes, B. ciliobracteata, B. microsperma, B. oxyloba, B. staudtii). 4.2.4 Montane forest (800-1500 m) The montane forest formation is characterized by an extremely low and <strong>of</strong>ten disjunct canopy, large numbers <strong>of</strong> trees, a low total basal area, and lower species richness than lowland and mid-elevation forests. The epiphytic flora is also particularly well developed. At <strong>the</strong>ir altitud<strong>in</strong>al limit, <strong>the</strong>se forests tend to be restricted to valley bottoms and water courses where <strong>the</strong>y form dist<strong>in</strong>ctive “gallery” forests. The dom<strong>in</strong>ant woody species <strong>in</strong> <strong>the</strong> montane forest are Syzygium gu<strong>in</strong>eense (Figure 5), Xylopia staudtii, Macaranga occidentalis, Santiria trimera, Harungana madagascariensis, Bridelia micrantha, Anthonotha cladantha, Bridelia grandis, Sapium cornutum, Polyscias fulva, and Vernonia conferta. O<strong>the</strong>r species seem<strong>in</strong>gly restricted to montane forest <strong>in</strong>clude Anthocleista vogelii, Barteria nigritiana, Bersama abys<strong>in</strong>ica, Blighia unijugata, Calycosiphonia macroclamys, Craterosiphum montanum, Dactyladenia staudtii, Dracaena arborea, Eugenia spp., Ficus thonn<strong>in</strong>gii, F. vogeliana, Hannoa kla<strong>in</strong>eana, Homalium doligophyllum, Hymenocardia acida, Maran<strong>the</strong>s glabra, Margaritaria discoidea, Olea capensis, Psychotria mannii, P. camptopus, Sapium cornutum, Sapium ellipticum, Schefflera abyss<strong>in</strong>ica, Serican<strong>the</strong> sp., Synsepalum brevipes, Trichilia monodelpha, Vernonia conferta, and Xylopia acutiflora. The herbaceous layer is dom<strong>in</strong>ated by many members <strong>of</strong> <strong>the</strong> Costaceae (particularly Costus lucanusianus) and <strong>the</strong> Z<strong>in</strong>giberaceae (Aframomum pilosum and A. arund<strong>in</strong>aceum) as well as Dracaena phrynoides. <strong>Takamanda</strong>: <strong>the</strong> Biodiversity <strong>of</strong> an African Ra<strong>in</strong>forest 4.2.5 High-altitude grassland This unique vegetation community forms a small part <strong>of</strong> TFR plant communities and as such does not warrant a detailed discussion for purposes <strong>of</strong> this chapter. Significant work has been undertaken on vegetation <strong>of</strong> Obudu Plateau <strong>in</strong> Nigeria, just across <strong>the</strong> border, and a number <strong>of</strong> checklists and vegetation descriptions <strong>of</strong> this high-altitude grassland have been published (Tuley 1966, Hall and Medler 1975a and b, Medler and Hall 1975, Keay 1979, Chapman and Chapman 2001). The transition zone between montane forest and grassland is comprised <strong>of</strong> large herbs and woody shrubs such as A. arund<strong>in</strong>aceum, Brilliantasia lamium, and Dichaetan<strong>the</strong>ra africana. The bracken Pteridium aquil<strong>in</strong>um subsp. aquil<strong>in</strong>um is also a common component <strong>of</strong> this transition zone, as is <strong>the</strong> spectacular Lobelia columnaris. The grassland is composed <strong>of</strong> a number <strong>of</strong> gregarious Gram<strong>in</strong>ae: Hyparrhenia diplandra, H. familiaris, H. rufa, H. bracteata, Andropogon auriculatus, Setaria anceps, Monocymbium ceeresiiforme, Loudetia camerunensis, Panicum hochstetteri, Eragrostis tenuifolia, and E. cameroonensis. Colonists <strong>in</strong>clude many small herbs and woody shrubs, notably Ageratum sp., Aspilia africana, Bartsia petitiana, Desmodium repandum, Oldenlandia sp. Cyanotis barbata, and Kyll<strong>in</strong>ga. In <strong>the</strong> small peaty hollows <strong>of</strong> exposed rocks, <strong>the</strong> t<strong>in</strong>y <strong>in</strong>sectivorous Utricularia mannii is also relatively common. 5 Discussion 5.1 Montane Forest <strong>Zone</strong>s As has been observed elsewhere (for example, Morton 1986), <strong>Takamanda</strong> forests are divided <strong>in</strong>to different vegetation types characterized by elevation and degree <strong>of</strong> exposure. The upper reaches <strong>of</strong> <strong>Takamanda</strong> Forest Reserve give way to grassland at an elevation <strong>of</strong> 1500 m. Though this comprises a low total area <strong>of</strong> <strong>the</strong> reserve, it is <strong>in</strong>terest<strong>in</strong>g to note <strong>the</strong> low altitude at which it occurs. At Mount Cameroon, <strong>the</strong> grassland habitat does not start until 2000 m (Richards 1963b), a characteristic observed
Vegetation Assessment Figure 5. Structure and composition <strong>of</strong> montane forest habitat <strong>in</strong> <strong>Takamanda</strong> Forest Reserve, Cameroon, from biodiversity plots, show<strong>in</strong>g relative dentity and relative basal area by (a) species, and (b) family. (a) Syzygium gu<strong>in</strong>eense Xylopia staudtii Santiria trimera Symphonia globulifera Macaranga occidentalis Harungana madagascariensis Bridelia micrantha Anthonotha cladantha Sapium cornutum Vepris sp. (b) Myrtaceae Euphorbiaceae Guttiferae Annonaceae Burseraceae Leg-Caesalp<strong>in</strong>ioideae Compositae Sapotaceae Rutaceae Rubiaceae Relative Density Relative BA 0 5 10 15 20 Relative Density Relative BA 0 5 10 15 20 25 31 SI/MAB Series #8, 2003