East African Afroalpine Helichrysum Scrubby Páramo

This is another very striking and characteristic community of the afroalpine belt, and can be found on Kilimanjaro, for example, at altitudes of 4100 to 4300 m. It is dominated by various endemic, shrubby members of the genus Helichrysum (Asteraceae), and is particularly impressive on Ruwenzori where the dominant species Helichrysum stuhlmannii forms a thicket up to 2 m high. The main species on other mountains are H. newi on Virunga, H. amblyphyllum and H. citrispinum on Elgon, H. chionoides and H. newi on Aberdare, H. browneii, H. chionoides and H. citrispinum on Mt Kenya, and H. citrispinum and H. newii on Kilimanjara. The associated ground flora varies from place to place, but on Mount Kenya normally comprise a discontinuous stand of endemic grasses such as Agrostis leptophylla, A. trachyphylla, Calamagrostis hedbergii and Pentaschistis minor (Poaceae), while some of more common forbs include the endemic Nannoseris schimper and Senecio keniophytum (Asteraceae). On Kilimanjaro the endemic ground flora include grasses such as Festuca kilimanjarica and Pentaschistis borussica (Poaceae) together with Euryops dacrydioides and Senecio meyeri-johannis (Asteraceae).

East African Afroalpine Alchemilla Scrubby Páramo

Shrubby alchemillas are another unusual feature of the afromountains. Most species in this genus are herbaceous, but here they form extensive scrublands. They include by a number of endemic species.  Alchemilla johnstonii is often dominant but in slightly dryer areas A. argyrophylla, A. elgonensis, and A. subnivalis become prominent. Ground layer species vary from mountain to mountain, but on Elgon normally include endemics such as Poa schimperiana (Poaceae), Valeriana kilimandscharica (Valerianaceae), Veronica glandulosa (Scrophulariaceae) and Viola eminii (Violaceae). Other endemic species often associated with this type of vegetation include Agrostis mildbraedii (Poaceae), Helichrysum newii (Asteraceae), Heracleum elgonense (Apiaceae) and Lobelia elgonensis (Campanulaceae).

East African Afroalpine Tussock Grass Páramo

Dominated by tufted, mostly endemic grasses such as Agrostis trachyphylla, A. volkensii, Andropogon amethystinus, Festuca abyssinica, F. kilimanjarica, F. pilgeri, Koeleria gracilis, Poa leptoclada and species Pentaschistis (Poaceae) this is one of the most widespread vegetation types in the afroalpine belt, particularly on dryer mountains such as Elgon, Mount Kenya and Kilimanjaro.  The associated vascular plants vary from site to site, but on Mount Kenya normally include a mixture of non-endemics such as Arabidopsis thaliana and Cardamine oblique and endemics such as Galium glaciale (Rubiaceae) and Senecio purtschelleri (Asteraceae), while on Kilimanjaro other endemics may include Haplosciadium abyssincia (Apiaceae) and Satureja kilimandschari (Lamiaceae).  On the wetter Rumenzori a different assemblage of grasses are present including the widespread Descampsia caespitosa and the endemic Anthoxanthum nivale (Poaceae), but grasslands here are relatively scarce. This is also true for Mount Meru where one of the most important grasses is the local endemic Pentaschistis meruensis (Poaceae).

East African Afroalpine Carex bog Páramo

In the lower, more level parts of the afroalpine belt where drainage is impeded there are bogs dominated by endemic, tussock-forming sedges.  The main dominants are either Carex monostachya or C. runssoroensis (Cyperaceae), but the habitat is given a strange appearance by the presence of endemic giant lobelias (Campanulaceae). As the main sub-dominants these include Lobelia bequaertii on Ruwenzori, L. elgonensis on Elgon, L. sattimae of Aberdare and L. deckenii on Kilimanjaro. Other endemic plants may include Kenichloa chionogeiton (Poaceae), Luzula abyssinica, L. johnstonii (Juncaceae), Ranunculus stagnalis, R. volkensii (Ranunculaceae), Romulea keniensis (Iridaceae), Sagina afroalpina (Caryophyllaceae), Senecio transmarinus (Asteraceae) and Subularia monticola (Brassicaceae).  The lower layers, however, are mainly dominated by sphagna and other bryophytes including endemic species such as Meesia kenyae and Scapania hedbergii on Mt Kenya, and Sematophyllum elgonense on Elgon. 

Cameroonian Afroalpine Scrubby Páramo

Between mountain forest and mountain grasslands there is a zone of fringing scrub. On Mount Cameroon the characteristic species of this zone include Philippa mannii and the endemic Satureja robusta (Lamiaceae). Field layer plants include various herbs and grasses, but also characteristic of this zone is the giant endemic Lobelia columnaris (Campanulaceae). This species represents West Africa’s nearest approach to the spectacular giant lobelias of the afro-montane floras of East African

Cameroonian Afroalpine Grassland Páramo

On Mount Cameroon’s upper escarpments and summit areas at altitudes ranging from 3500-3960 m mountain grasslands predominate. In the coarse lava fragments and ash zones on the summit where sulphurous fumes discharge from various fissures the endemic grass Pentaschistis mannii (Poaceae) forms widely spaced tussocks. All other plants are dwarfed to just a few cm including the shrubbly ericoids Blaeria mannii and Philippa mannii. At lower levels where conditions are less harsh the endemic Deschampsia mildbraedii (Poaceae) becomes the main grass species, which in places can exceed 30 cm in height. Other common species are Luzula campestris, Senecio clarenceanus and the endemic Helichrysum mannii (Astaeraceae) and Veronica mannii (Scrophulariaceae). However, on very steep slopes Bulbostylis erratica and Festuca abyssinica becomes a feature of the vegetation together with the endemic Silene biafra (Caryophyllaceae). These upland grasslands have been likened to the paramos of the tropical Andes. However, the tree-like Dendrosenecio and Lobelia species so characteristic of the East African mountains such as Ruwenzory are lacking. Only Crassocephalum manni in its young stages, and the endemic Lobelia columnaris (Campanulaceae) come close to these physiognomic types.

Zambezian Afromontane Dambo Grass Páramo

At altitudes above about 1200m where drainage is sluggish up to 20% of plateau surfaces are covered in a dense grass mats known as dambos. The soils are usually acidic, and much of it is subject to seasonal flooding, but in the dry season it may dry out and become very compact. Their floristic composition shows considerable variation, but is by and large, composed of fine leaved grasses, together with a number of Cyperaceae and Xyridaceae. The most characteristic grass is Loudetia simplex, while other common grass species include Andropogon schirenss, Hyparrhenia bracteata, Miscanthus teretifolius, Monocymbium ceresiiforme, Themeda triandra and Trachypogon spicatus. Endemic grasses found here include Brachiaria clavipila, Digitaria bidactyla, D. complanata, D. hyalina, D. phaeotricha, many Eragrostis species such as E. acamptoclada, E. anacrantha, E. astreptoclada, E. aurorae, E. caniflora, E. castellaneana, E. dentifera, E. friesii, E. mariae, E. milnei, E. oligostachya and E. saresberiensis, Lophacme parva and Sporobolus fibrosus (Poaceae).    In the wetter areas there can be a great variety of Cyperaceae including Ascolepis anthemiflora, Bulbostylis cinnamomea, Cyperus esculentus, Fuirena pubescens, Kyllinga erecta, Mariscus deciduus, Pycreus aethiops, Scirpus microcephalus and Scleria bulbifera. Among the endemic forbs found here are a wide variety of orchids such as Centrostigma clavatum and C. papillosum, and species of Brachycorythis, Disa, Habenaria, Platycoryne and Satyrium, while endemics from other plant families include Acalypha clutioides (Euphorbiaceae), Aeschynomene mediocris (Fabaceae), Ageratinastrum palustre (Asteraceae), Anagallis elegantula (Primulaceae), Buchnera ciliolata (Scrophulariaceae), Dierama parviflorum (Iridaceae), Dissotis gilgiana (Melostomataceae), Eugenia malagensis (Myrtaceae), Hydrolea brevistyla (Hydrophyllaceae), Hypoxis nyasica (Hypoxidaceae), Ipomoea fanshawei (Convolvulaceae), Kniphofia reynoldsii (Asphodelaceae), Mechowia redactifolia (Amaranthaceae), Nesaea spathulata (Lythraceae), Sebaea gracilis (Gentianaceae) and Spermacoce annua (Rubiaceae).

Zambezian Afromontane Grass Páramo

Confined to uplands such as the Nyika and Mafinga Hills both of these grassland types are composed of short and tufted grasses. The dominant species often include Exothecia abyssinica, Loudetia simplex, Monocymbium ceresiiforme and Trachypogon spicatus, while the many endemic grasses are Allaeochaete geniculata (Mt Mulanje), A. namuliensis, A. oreogena (Mt Mulanje), Eragrostis canescens, E. desolata, (Mt Chimanimani), E. fastigiata (Mt Mulanje), E. sylviae (Mt Mulanje), Panicum eickii, P. inaequilatum, P. lukwangulense and Rytidosperma davyi.  These grasslands are also very rich in orchid species with some of the endemic species represented by Brownleea mulanjiensis (Mt Mulanje), Cynorkis brevicalcar (Mt Mulanje), Disa zombica, Habenaria xanthochlora, Herschelianthe longilabris, Holothrix tridactylites, Liparis rungweensis, Neobolusia ciliata, Polystachya lawrenceana, Roeperocharis wentzeliana, many species of Satyrium including S. buchananii, S. microcorys, S. monadenum, S. oliganthum, S. princeae, S. rhynchantoides and species of Schizochilus including S. calcaratus, S. lepidus, S. sulphureus. But these rich grasslands support many other endemic species with herbaceous examples including Ageratinastrum polyphyllum (Asteraceae), Aloa rhodesiana (Aloaceae), Clutia swynnertonii (Euphorbiaceae), Cynoglossum inyangense (Boraginaceae), Gladiolus zimbabweensis (Iridaceae), Impatiens schulziana (Nyika Plateau) (Balsaminaceae), Kniphofia reynoldsii (Asphodelaceae), Pentas lindenioides (Rubiaceae), Phyllanthus tsetserrae (Euphorbiaceae), Swertia johnstonii (Gentianaceae), Trachyandra malosana (Asphodelaceae) and Walafrida swynnertonii (Scrophulariaceae).

References

Boughey, A. S. 1953. The vegetation of the mountains of Biafra. Proceedings of the Linnean Society of London, 165: 144-150.

Burtt, B. D. 1934. XVII – A. Botanical reconnaissance in the Virunga volcanoes of Kigezi Ruanda, Kivu. Bulletin of Miscellaneous Information, Royal Botanic Gardens, Kew. No. 4: 145-165.

Cable, S. & Cheek, M. 1998. The Plants of Mount Cameroon. Royal Botanic Gardens, Kew.

Grimshaw, J. M. 1998. Disturbance, Pioneers and the Afromontane Archipelago. In: Chorology, Taxonomy and Ecology of the Floras of Africa and Madagascar. Eds. J. M. Lock and D. F Cutler. Royal Botanic Gardens, Kew.

Hall, J. B. 1973. Vegetation zones on the southern slopes of Mount Cameroon. Vegetatio, 27: 49-69.

Hedberg, O. 1951. Vegetation belts of the east African mountains. Svensk Botanisk Tidskrift, 45: 141-202.

Hedberg, O. 1957. Afroalpine Vascular Plants - A Taxonomic Revision. Uppsala

Hedberg, O. 1964. Features of  Afroalpine plant ecology. Acta Phytogeographica Suecica, 49: 1-144.

Hedberg, O. 1965. Afroalpine Flora Elements. Webbia, 19: 519-529.

Hedburg, O. 1986. Origins of the Afroalpine flora. In: High Altitude Tropical Biogeography. Eds F. Vuilleumier and M. Monasterio. Oxford University Press and American Museum of Natural History.

Morton, J. K. 1986. Montane Vegetation. In: Plant Ecology in West Africa. Ed. G. W. Lawson. John Wiley & Sons Ltd.

O’Conner, T. G. 2005. Influence of land use on plant community composition and diversity in Highland Sourveld grassland in southern Drakensberg, South Africa. Journal of Applied Ecology, 42: 975-988.

Schmitt, K. & Bayreuth, E. B. 1992. On the afroalpine vegetation of the Ruwenzori Mountains, Uganda. Phytocoenologia, 21: 313-332.

Snowden, J. D. 1933. A study in altitudinal zonation in south Kigezi and on Mounts Muhavure and Mgahinga. Uganda. Journal of Ecology, 21: 7-27.

White, F. 1978. The Afro-Alpine Region. In: Biogeography and Ecology of southern Africa. Ed. M. J. A. Werger. Dr W Junk Publishers. The Hague.

White, F. 1978. The Afromontane Region. In: Biogeography and Ecology of southern Africa. Ed. M. J. A. Werger. Dr W Junk Publishers. The Hague.

White, F. 1983. The Vegetation of Africa. UNESCO.