Savannah Ecology 2/5: Variation

In Kenya, the savannah is basically dry, grass and shrub savannah. This means that most of it is covered in various kinds of grass, with occasional small bushes, and rarer larger trees. Of course, where there are rivers, or underground water sources, there will be more vegetation, and there is also quite a lot of local variation within the basic pattern. Amboseli, for example, lies in the rain shadow of Mount Kilimanjaro, and is rather dry, but has underground water sources to provide 'swamps' for a part of its area.

Thus, the animals tend to concentrate in Region 3 (or the north of Region 2) in the dry season and return south and east in the wet season. Although Region 3 also receives rain in the wet season, having been cropped in the dry season, and covering a smaller area in any case, there will be a lot less food here at this time.

Although the Serengeti and Maasai Mara are effectively one block, there is quite a variation between different regions. If there were not, there would be no migration of wildebeest and other animals.

Region 1, in the shadow of the Crater Highlands (over 3,000m), receives lowish rainfall in the rainy season (November to March), and very low rain in the dry season (April to October).

Region 2, receives a lot more rain in the rainy season than Region 1, but not much rain in the dry season.

Region 3, due to the influence of Lake Victoria, receives significant amounts of rain during the dry season also.

The diagram and explanation is a very simplified version of information presented in Bryan Shorrocks, 2007,The Biology of African Savannahs, which in turn refers to work by A R E Sinclair and S J McNaughton