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Predicted Impact of Barriers to Migration on the Serengeti Wildebeest Population

2011; Public Library of Science; Volume: 6; Issue: 1 Linguagem: Inglês

10.1371/journal.pone.0016370

1932-6203

Ricardo M. Holdø, John M. Fryxell, A. R. E. Sinclair, Andrew P. Dobson, Robert D. Holt,

Ecology and biodiversity studies

The Serengeti wildebeest migration is a rare and spectacular example of a once-common biological phenomenon. A proposed road project threatens to bisect the Serengeti ecosystem and its integrity. The precautionary principle dictates that we consider the possible consequences of a road completely disrupting the migration. We used an existing spatially-explicit simulation model of wildebeest movement and population dynamics to explore how placing a barrier to migration across the proposed route (thus creating two disjoint but mobile subpopulations) might affect the long-term size of the wildebeest population. Our simulation results suggest that a barrier to migration—even without causing habitat loss—could cause the wildebeest population to decline by about a third. The driver of this decline is the effect of habitat fragmentation (even without habitat loss) on the ability of wildebeest to effectively track temporal shifts in high-quality forage resources across the landscape. Given the important role of the wildebeest migration for a number of key ecological processes, these findings have potentially important ramifications for ecosystem biodiversity, structure, and function in the Serengeti.