Theme 23: Biodiversity
Description
Field observations in the Serengeti National Park, Tanzania have revealed several modes of grazing system, including migration, sustained-yield grazing and grazing succession which contribute on the one hand to ecological separation of herbivores by habitat choice, but on the other hand to positive association of species on wet season pastures known as hot spots. Drawing from results of experimental field studies, we consider what is known about resource competition and facilitation, the two key ecological processes underlying these grazing systems, and specify the shape of the relationship between species richness and pasture height that is predicted depending on which process is dominating in the grazing system. We test between these alternatives by analysing for the first time data on herbivore distributions and vegetation condition from a series of 33 survey flights over the entire Serengeti ecosystem. Our preliminary results strongly support the importance of facilitation as a process structuring the herbivore community of the Serengeti Plains in the wet season. Resource competition may limit use of the shortest swards.
Included in
The Influence of Large Animal Diversity in Grazed Ecosystems
Field observations in the Serengeti National Park, Tanzania have revealed several modes of grazing system, including migration, sustained-yield grazing and grazing succession which contribute on the one hand to ecological separation of herbivores by habitat choice, but on the other hand to positive association of species on wet season pastures known as hot spots. Drawing from results of experimental field studies, we consider what is known about resource competition and facilitation, the two key ecological processes underlying these grazing systems, and specify the shape of the relationship between species richness and pasture height that is predicted depending on which process is dominating in the grazing system. We test between these alternatives by analysing for the first time data on herbivore distributions and vegetation condition from a series of 33 survey flights over the entire Serengeti ecosystem. Our preliminary results strongly support the importance of facilitation as a process structuring the herbivore community of the Serengeti Plains in the wet season. Resource competition may limit use of the shortest swards.
