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Harvard University

Publication Date

Fall 2011

Program Name

Australia: Rainforest, Reef, and Cultural Ecology

Abstract

Trophic regulation of mesopredators through top order predators can have profound effects on ecosystem community and diversity. In the absence of top predators, invasive mesopredators exert strong selective pressures on native prey and can alter prey foraging behavior. When foraging in the presence of predators, prey must weigh predation risk against food gain. To examine the indirect impacts of dingo baiting on risk sensitive foraging in forests, we measured differences in giving up densities (GUDs) and surveyed local populations of mesopredators and mammals. We hypothesized that in baited areas, mesopredators would be more abundant and prey would perceive greater predation risk. Foraging trays of peanuts were placed in baited and nonbaited study areas for four nights and the remaining peanuts measured as the GUD. A higher density of mesopredators and a lower density of small mammals was observed in baited versus nonbaited study sites. Consistent with foraging theory, rodents perceived significantly greater predation risk in baited areas than nonbaited areas. However, abundance of medium and large mammals was not affected by baiting regime. Ecosystem conservation management has strongly focused on baiting of invasive predators in protected reserves. Our study suggests removal of a top predator positively affects mesopredator abundance and negatively affects small mammals in forests. For sustainable forest management, reconsideration of baiting regimes may be necessary to optimize ecosystem diversity and structure.

Disciplines

Ecology and Evolutionary Biology | Environmental Policy

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