The Serengeti Ecosystem Region (abbreviated as SER) is an area of 25,000 km², found south of the Tanzania and Kenya border between 2° and 4° S, defined by the movement of migratory wildebeest (McNaughton 1983). The Serengeti National Park (established in 1940, 14,700 km²) and the Ngorongoro Conservation Area (established in 1959, 8,300 km²) form the majority of the SER. Both are also designated by UNESCO as World Heritage Sites and Biosphere Reserves. There are a further five smaller reserves surrounding the Serengeti National Park; Maswa in the south; Grumeti, Ikoma, and Ikorongo in the east and the Loliondo Game Controlled Area in the west (World Bank 1993). Over the border in Kenya and contiguous to the Serengeti National Park is the Masai Mara National Reserve (World Bank 1993).

Vegetation

The SER is part of White's Somalia-Masia vegetation type (White 1983). The Serengeti plains which range from 1600-1800 m are characterised by "short" and "tall" grasslands and woody savanna with rocky outcrops called "kopje" (Anderson and Talbot 1965, Lind and Morrison 1974, Herlocker 1975). The short grasslands in the east are dominated by Sporobolus and Kyllinga species whilst in the west the tall grasslands are dominated by Pennisetum, Andropogon and Themeda species (Lind and Morrison 1974). Intermediate grasslands of Cynodon and Sporobolus are found between the short and tall grassland areas. Seventeen different grassland communities have been characterised (McNaughton 1983) : six short grassland communities, three tall and eight medium. The distribution and growth of grass species in the Serengeti plains depends on a number of factors including soil depth and texture, salt concentration, degree of wind erodability, rainfall and grazing pressure (Anderson and Talbot 1965Lind and Morrison 1974).

The Ngorongoro Conservation Area is dominated by a volcano formed 5-7 million years ago with a large central caldera formed 1-2 million years ago (Anderson and Herlocker 1973). The crater reaches over 3350 m high but the crater floor is lower at 1737 m (Anderson and Herlocker 1973). The main vegetation types are grasslands, swamps, montane heath and woodland (Herlocker and Dirschl 1972). Similar to the Serengeti plains, the distribution of the Ngorongoro grasslands are influenced by soils, climate, grazing pressures and fire (Anderson and Herlocker 1973).

Species

The grass flora of Tanzania is documented through the Flora of Tropical East Africa (Clayton et al. 1970, Clayton et al. 1974, Clayton and Renvoize 1982). Grassland ecology in the SER has been well studied (for example Anderson and Talbot 1965, McNaughton 1983) but these studies have focused on community structure and distribution not on species composition. There are also vegetation maps for the Serengeti woody species (Herlocker 1975) and the Ngorongoro Conservation Area (Herlocker and Dirschl 1972) but full species checklists are not included. Therefore there is a requirement for a checklist of grass species to support ecological studies on the flora and fauna of the SER.