Afromontane Flora
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The Afromontane regions are subregions of the
Afrotropical realm The Afrotropical realm is one of the Earth's eight biogeographic realms. It includes Sub-Saharan Africa, the southern Arabian Peninsula, the island of Madagascar, and the islands of the western Indian Ocean. It was formerly known as the Ethiopi ...
, one of the Earth's eight
biogeographic realm A biogeographic realm is the broadest biogeography, biogeographic division of Earth's land surface, based on distributional patterns of terrestrial animal, terrestrial organisms. They are subdivided into bioregions, which are further subdivid ...
s, covering the plant and animal species found in the mountains of
Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...
and the southern
Arabian Peninsula The Arabian Peninsula (, , or , , ) or Arabia, is a peninsula in West Asia, situated north-east of Africa on the Arabian plate. At , comparable in size to India, the Arabian Peninsula is the largest peninsula in the world. Geographically, the ...
. The Afromontane regions of Africa are discontinuous, separated from each other by lower-lying areas, and are sometimes referred to as the Afromontane archipelago, as their distribution is analogous to a series of sky islands.


Geography

Afromontane communities occur above elevation near the equator, and as low as elevation in the Knysna-Amatole montane forests of
South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...
. Afromontane forests are generally cooler and more humid than the surrounding lowlands. The Afromontane archipelago mostly follows the
East African Rift The East African Rift (EAR) or East African Rift System (EARS) is an active continental rift zone in East Africa. The EAR began developing around the onset of the Miocene, 22–25 million years ago. It was formerly considered to be part of a l ...
from the
Red Sea The Red Sea is a sea inlet of the Indian Ocean, lying between Africa and Asia. Its connection to the ocean is in the south, through the Bab-el-Mandeb Strait and the Gulf of Aden. To its north lie the Sinai Peninsula, the Gulf of Aqaba, and th ...
to
Zimbabwe file:Zimbabwe, relief map.jpg, upright=1.22, Zimbabwe, relief map Zimbabwe, officially the Republic of Zimbabwe, is a landlocked country in Southeast Africa, between the Zambezi and Limpopo Rivers, bordered by South Africa to the south, Bots ...
, with the largest areas in the
Ethiopian Highlands The Ethiopian Highlands (also called the Abyssinian Highlands) is a rugged mass of mountains in Ethiopia in Northeast Africa. It forms the largest continuous area of its elevation in the continent, with little of its surface falling below , whil ...
, the Albertine Rift Mountains of
Uganda Uganda, officially the Republic of Uganda, is a landlocked country in East Africa. It is bordered to the east by Kenya, to the north by South Sudan, to the west by the Democratic Republic of the Congo, to the south-west by Rwanda, and to the ...
,
Rwanda Rwanda, officially the Republic of Rwanda, is a landlocked country in the Great Rift Valley of East Africa, where the African Great Lakes region and Southeast Africa converge. Located a few degrees south of the Equator, Rwanda is bordered by ...
,
Burundi Burundi, officially the Republic of Burundi, is a landlocked country in East Africa. It is located in the Great Rift Valley at the junction between the African Great Lakes region and Southeast Africa, with a population of over 14 million peop ...
,
Democratic Republic of the Congo The Democratic Republic of the Congo (DRC), also known as the DR Congo, Congo-Kinshasa, or simply the Congo (the last ambiguously also referring to the neighbouring Republic of the Congo), is a country in Central Africa. By land area, it is t ...
, and
Tanzania Tanzania, officially the United Republic of Tanzania, is a country in East Africa within the African Great Lakes region. It is bordered by Uganda to the northwest; Kenya to the northeast; the Indian Ocean to the east; Mozambique and Malawi to t ...
, and the
Eastern Arc The Eastern Academic Research Consortium, or "Eastern Arc", is a regional research collaboration between the University of East Anglia, the University of Essex, the University of Kent and the University of Sussex. The four partner institutions ar ...
highlands of
Kenya Kenya, officially the Republic of Kenya, is a country located in East Africa. With an estimated population of more than 52.4 million as of mid-2024, Kenya is the 27th-most-populous country in the world and the 7th most populous in Africa. ...
and Tanzania. Other Afromontane regions include the Drakensberg range of southern Africa, the Cameroon Highlands, and the Cameroon Line volcanoes, including Mount Cameroon, Bioko, and São Tomé Island, São Tomé.


Flora

Although some Afromontane enclaves are widely separated, they share a similar mix of plant species which are often distinct from the surrounding lowland regions. Podocarps, of genera ''Podocarpus'' and ''Afrocarpus'', are a characteristic tree, along with ''Prunus africana'', ''Hagenia abyssinica'', ''Juniperus procera'', and ''Olea spp.''. In the higher mountains, the Afromontane forest or woodland zone transitions to a higher Afroalpine zone of grasslands, shrublands, or moorlands. The plant families Curtisiaceae and Oliniaceae are Afromontane endemics and family Barbeyaceae is a near-endemic. The tree genera ''Cornus, Afrocrania, Balthasaria, Curtisia, Ficalhoa, Hagenia, Kiggelaria, Kuloa, Leucosidea, Platypterocarpus, Trichocladus,'' ''Widdringtonia'', and ''Xymalos'' are Afromontane endemics or near-endemics, as are the plant genera ''Ardisiandra, Cincinnobotrys,'' and ''Stapfiella''.


Plant communities

Afromontane areas have a wide range of plant communities, including intermediate types. These include: * Afromontane rain forest. Afromontane rain forest is found on wetter slopes from southern Ethiopia to Malawi, mostly between 1200 and 2500 meters elevation. It occurs on wetter slopes where average annual rainfall is from 1250 to 2500 mm, or higher. Elevation and location varies somewhat based on distance from the equator or from the sea, and the size and configuration of the highland where it occurs. Mature rain forests generally have an upper stratum of trees 25 to 45 meters high, a middle stratum 14 to 30 meters high, a lower stratum 6 to 15 meters high, a shrub layer of 3 to 6 meters high, and a sparse herbaceous ground layer. The tree crowns of the upper strata are typically open, and the middle strata may be continuous but rarely forms a dense canopy, while the lower tree stratum is typically dense. Most trees are evergreen. Afromontane rain forests can be similar in structure to lowland Guineo-Congolian region, Guineo-Congolian rain forests, but the species mostly differ from lowland forests. Typical trees include ''Aningeria adolfi-friederici, Cola greenwayi, Cylicomorpha parviflora, Diospyros abyssinica, Drypetes gerrardii, Entandrophragma excelsum, Ficalhoa laurifolia, Gambeya gorungosana, Kuloa usambarensis, Mitragyna rubrostipulata, Myrianthus holstii, Ochna holstii, Olea capensis, Parinari excelsa, Podocarpus milanjianus, Prunus africana, Strombosia scheffleri'', Syzygium guineense, ''Syzygium guineense'' subsp. ''afromontanum'', ''Tabernaemontana johnstonii'', and ''Xymalos monospora''. Tree ferns (''Cyathea'' spp.), lianas, and epiphytes, including ferns, mosses, and species of ''Begonia, Impatiens, Streptocarpus'', and ''Peperomia'', are abundant.


Distribution

In
South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...
, Afromontane forests cover only 0.5% of the country's land area. The Afromontane forests occur along the mountainous arc of the Drakensberg Range, from Limpopo Province in the northeast to the Western Cape Province in the southwest. The Afromontane forests generally occur in well-watered areas, including ravines and south-facing slopes. The Afromontane forests are intolerant of fire, and the frequent fires of the surrounding fynbos, savanna, and grassland limit the expansion of the forests. Despite their small area, the Afromontane forests of South Africa produce valuable timber, particularly the real yellowwood ''(Podocarpus latifolius)'', Afrocarpus, Outeniqua yellowwood ''(Afrocarpus falcatus)'', and Ocotea bullata, stinkwood ''(Ocotea bullata)''.


Afromontane ecoregions

;Tropical and subtropical moist broadleaf forests * Albertine Rift montane forests (Democratic Republic of the Congo, Burundi, Rwanda, Tanzania, Uganda) * Cameroonian Highlands forests (Cameroon, Nigeria) * East African montane forests (Kenya, South Sudan, Tanzania, Uganda) * Eastern Arc forests (Tanzania, Kenya) * Ethiopian montane forests (Djibouti, Eritrea, Ethiopia, Somalia, Sudan) * Guinean montane forests (Guinea, Côte d'Ivoire, Liberia, Sierra Leone) * Knysna-Amatole montane forests (South Africa) * Southern Afrotemperate Forest (Western Cape Province of South Africa) * Mount Cameroon and Bioko montane forests (Cameroon, Equatorial Guinea) ;Montane grasslands and shrublands, Montane grasslands, shrublands, and woodlands * Angolan montane forest-grassland mosaic (Angola) * Angolan scarp savanna and woodlands (Angola) * Drakensberg alti-montane grasslands and woodlands (Lesotho, South Africa) * Drakensberg montane grasslands, woodlands and forests (Lesotho, South Africa, Eswatini) * East African montane moorlands (Kenya, South Sudan, Tanzania, Uganda) * Eastern Zimbabwe montane forest-grassland mosaic (Mozambique, Zimbabwe) * Ethiopian montane grasslands and woodlands (Eritrea, Ethiopia) * Ethiopian montane moorlands (Ethiopia) * Highveld grasslands (Lesotho, South Africa) * Jos Plateau forest-grassland mosaic (Nigeria) * Maputaland-Pondoland bushland and thickets (Mozambique, South Africa, Eswatini) * Southern Afrotemperate Forest (Western Cape Province of South Africa) * Rwenzori-Virunga montane moorlands (Democratic Republic of the Congo, Rwanda, Uganda) * South Malawi montane forest-grassland mosaic (Malawi, Mozambique) * Southern Rift montane forest-grassland mosaic (Malawi, Tanzania) ;Deserts and xeric shrublands * Southwestern Arabian montane woodlands (Saudi Arabia, Yemen)


External links


Eastern Afromontane Biodiversity Hotspot (Conservation International)



References

{{Reflist * Galley, C. & Linder, H. P. (2006) Geographical affinities of the Cape flora, South Africa. ''Journal of Biogeography'' 33 (2), 236–250. Afromontane, Afrotropical ecoregions Tropical and subtropical moist broadleaf forests Montane grasslands and shrublands Deserts and xeric shrublands Ecoregions of Africa Ecoregions of Saudi Arabia Ecoregions of Yemen Flora of Africa, * Flora of the Arabian Peninsula, *