Serengeti General Management Plan

Serengeti National Park General Management Plan
small dicotyledonous plants. With the deeper soils to the west and north, grass species
change, the dominant species being Themeda triandra and Pennisetum mezianum. The
woodlands are dominated by Acacia species in all areas except for a small region south and
west of Kogatende, where Terminalia-Combretum takes over.
The Serengeti is well known not only for supporting the largest herds of migratory ungulates
but also one of the highest concentrations of predators in the world. In 1995, the predator
population was estimated to include about 7,500 hyenas, and 2,800 lions, with the highest
concentrations being in the Seronera valley where the perennial availability of water attracts
a wide range of antelope and other animals. There are over 500 species of birds that are
perennially or seasonally present in the Park, of which five species are endemic to Tanzania.
The Park has the highest Ostrich population in Tanzania and probably Africa, making the
population globally important.
Although the majority of systematic studies have concentrated on birds and the larger mammal
species, other studies have shown high biodiversity in other taxa. For example, twentyfive
species of toads and frogs have been recently recorded by Channing & Moyer (in press)
and over 100 species of dung beetles have been identified in the plains near Lake Lagarja
(Foster and Bresele in Sinclair and Arcese, 1995).
Self-regulating ecosystem
A growing understanding of the Serengeti ecosystem has highlighted that the ecosystem can
exist in multiple states of woodland or grassland, both spatially and temporally, and that longterm
natural change between different states within the ecosystem is a natural phenomenon.
Figure B.2 below illustrates the grassland-woodland dynamic and the main factors that cause
the transitions between stable states.
Figure B.2: Two alternative stable states of a savannah grassland
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Grassland state
High grass biomass leads to hot
fires, which kill tree seedlings.
Elephants are able to remove the
few establishing tree seedlings to
maintain grassland
Source: Bayona & Sharam (2001)
Repeated hot fires
(late dry season)
Removal of fire
Removal of elephants
Woodland state
Trees shade the grass and remove
water, thus reducing grass biomass
and fuel for hot season fires
Fire incidences, themselves modulated by rainfall patterns, are the main factor influencing
vegetation states, however, keystone species – e.g. wildebeest and elephants – can play an
important factor in maintaining and influencing these states through their grazing/ browsing
patterns. Conversely the ecosystem is self-regulating regarding wildlife numbers, through
either food availability (e.g. as for wildebeest) or predation (e.g. as with Thomson’s gazelle).