Dissertation Research: Food-limited to Habitat-limited: Predator-prey Uncoupled

University Of Pennsylvania, Philadelphia PA

Investigators

Abstract

Understanding the way in which predators interact with prey communities is a central challenge of ecology, and becomes more difficult and important in habitats disturbed by humans. Habitat destruction and nutrient enrichment, common anthropogenic effects on ecosystems, may shift systems from being prey-limited to being habitat-limited, with important consequences for predators. Predators may be less effective at controlling prey populations, and this likely has far-reaching effects on ecosystem characteristics. Pacific northwest streams provide a compelling example of these dynamics. Preliminary evidence for larval Pacific giant salamanders, dominant predators in old growth forest streams, suggests that logging shifts the ecosystem from being prey-limited to being habitat-limited. Experimental food and habitat addition at old growth and logged sites will determine whether salamander larvae are limited by habitat or by prey. Further, manipulating salamander densities and monitoring the prey community will determine the relative impact on the abundance and diversity of prey.