PARENT SESSION
Organized Oral Session 43: Complex consequences of spatial subsidies to food webs
Organizer(s): JM Kraus and WB Anderson
Thursday, August 11, 8:00 AM - 11:30 AM, Meeting Room 511 B, Level 5, Palais des congrès de Montréal

The seasonal migration of wildebeest in the Serengeti as a driver of community dynamics in resident herbivores and predators.

Holdo, Ricardo^*,1, Holt, Robert¹, ¹ Department of Zoology, Gainesville, FL, USA

ABSTRACT- The Serengeti ecosystem is characterized by seasonal migrations of wildebeest between grasslands and woodland savannas. Wildebeest are a keystone species in this system, and their seasonal movements represent an important spatial subsidy at both higher and lower trophic levels. The woodland habitat is characterized by resident herbivores and predators during the wet season, with wildebeest and other migrants moving into this habitat during the dry season, where they track ephemeral patches of green vegetation. At this time, wildebeest represent the dominant food resource for resident lions and hyaenas. We used a community module comprising resident predators and herbivores, a seasonally-fluctuating migrant herbivore population in a chemostat-type model with a resource (grass biomass) limited by rainfall to explore the dynamics and stability of this system, and to predict changes in predator and resident herbivore populations as the wildebeest migration is restricted. We discuss the consequences of changes in migration patterns in large ungulates for the structure of resident large mammal communities.

Key words: Serengeti, migration, spatial subsidies, ungulates