Using specific examples, describe how each of the following factors affect the vegetation of Africa; (a) Rainfall (b) Altitude (c) Soil type

Answer Details

(a) Rainfall

• The amount and duration of rainfall largely determine the type and density of vegetation.
• Areas of heavy, all-year rainfall (over 1,500 mm) near the equator support dense tropical rain forest, for example the Congo basin.
• Areas of moderate, seasonal rainfall support savanna grassland with scattered trees, for example the Sudan zone.
• Areas of very low rainfall support only sparse, drought-resistant scrub or desert vegetation, for example the Sahara. Thus vegetation becomes poorer as rainfall decreases.

(b) Altitude

• As altitude increases, temperature falls, so vegetation changes with height on high mountains (vertical zonation).
• On the East African mountains such as Kilimanjaro, the lower slopes carry rain forest, giving way upward to bamboo and montane forest, then montane grassland/moorland, and finally bare rock and snow at the summit.
• Highlands also receive more relief rainfall and are cooler, favouring temperate-type plants.

(c) Soil type

• The depth, texture and fertility of the soil control the plants that can grow.
• Deep, fertile, well-drained soils support luxuriant forest, for example the alluvial soils of river valleys.
• Thin, sandy or leached soils support only grasses and scrub, for example the sandy soils of the Sahel.
• Waterlogged, saline coastal soils support special vegetation such as mangroves in the Niger Delta, while swampy soils carry swamp forest.