Site description This forest complex covers a substantial area of the south-western highlands of Kenya, and probably represents the largest remaining near-continuous block of montane indigenous forest in East Africa. The forests cloak the western slopes, and part of the crest, of the Mau Escarpment, a block of raised land that forms the western wall of the Gregory Rift Valley, rising steeply from the floor and sloping away more gradually to the west. There are five main Forest Reserves: Eastern, Western and South-western Mau (c.66,000, 22,700 and 84,000 ha respectively), Trans-Mara (34,400 ha) and Ol Pusimoru (17,200 ha). A sixth large block, the Maasai Mau (c.46,000 ha) is as yet ungazetted. In early 2001, a total of 59,134 ha (35,301 in Eastern Mau, 22,797 ha in South-western Mau, 713 ha in Western May and 1,03 ha in Western Mau) was designated for degazettement. The Mau has deep, fertile, volcanic soils, and rainfall in places is among the highest in Kenya. Annual precipitation ranges from c.1,000 mm in the east, with a seasonal regime, to 2,000 mm in the west, where it is more-or-less continuous around the year. Numerous streams drain the forests west of the scarp crest, forming part of the Sondu and Mara river systems, which flow into Lake Victoria, and the Southern Ewaso Ngiro system, which flows into Lake Natron. The Eastern Mau is the main watershed for Lake Nakuru, through the Njoro, Makalia and Enderit rivers. The surrounding areas are intensively farmed, with human population densities about twice as high on the western side of the forest as on the east. Vegetation patterns are complex, but there is a broad altitudinal zonation from west to east, lower montane forest below 2,300 m giving way to thickets of bamboo Arundinaria alpina mixed with forest and grassland, and finally to montane sclerophyllous forest near the escarpment crest. The lower montane forest is in best condition in the South-western Mau Nature Reserve, where characteristic trees include Aningeria adolfi-friedericii and Strombosia scheffleri. Elsewhere, this zone has been heavily and destructively logged, most recently for plywood from Polyscias kikuyuensis. Logged-over areas are dominated by pioneer species such as Tabernaemontana stapfiana, Syzygium guineense and Neoboutonia macrocalyx, while pockets of less-disturbed forest hold Olea capensis, Prunus africana, Albizia gummifera and Podocarpus latifolius. Substantial parts of the high Juniperus-Podocarpus-Olea forest have been encroached and cleared, although some sections remain in good condition. Large areas of both the Eastern and Western Mau have been converted to plantation forest. |