PARENT SESSION
Oral Session # 71: Trophic Structure I: Theory; Aquatic Systems.
Presiding: D Chalcraft
Thursday, August 7. 8:00 AM to 11:30 AM, SITCC Meeting Room 202.

Resource or predator control of community structure: The importance of generalist and specialist predators.

Jiang, Lin^*,1, Morin, Peter¹, ¹ Rutgers University, New Brunswick, New Jersey

ABSTRACT- Ecologists have long recognized the importance of resources and predators in structuring ecological communities. Despite several decades of research, however, the question of what controls the relative strength of resource and predator limitation of community structure remains elusive. Using aquatic microcosms in which nutrient resources and predators were independently manipulated, we show that predator characteristics can largely determine the relative strength of resource and predator control of both species abundance and diversity of the middle trophic level in a food web with three trophic levels. Predation dominated in communities with generalist predators, whereas resource impacts were more important in communities with specialist predators. These results suggest that natural communities dominated by generalist predators and those dominated by specialist predators may exhibit differential responses to nutrient enrichment imposed by human activities.

Key words: species diversity, trophic structure, generalist predators, specialist predators