PARENT SESSION
Wednesday, August 9, 8:00-11:50 am
OOS 8 - When does fear matter? A road map to the implications of trait-mediated effects to ecology
Ballroom D, Ballroom Level, Cook Convention Center
Organized by: EL Preisser (preisser@psis.umass.edu), G Trussell, and E Werner

This session synthesizes mathematical theory, conceptual work, and empirical research to explore the factors influencing the relative importance of trait- and density-mediated effects in ecological communities.

Implications of the ecology of fear for invasion ecology.

Sih, Andrew^*,1, ¹ University of California, Davis, Davis, CA

ABSTRACT- An important issue in predator-prey ecology involves understanding variation in impacts of invasive predators on native communities. This symposium emphasizes that understanding prey behavioral responses to predation risk can be critical for explaining predator impacts; i.e., often, much of the impact comes through non-consumptive effects (NCEs). My focus here is on how antipredator behavior, and patterns of NCEs versus consumptive effects (CEs) influence predator invasions. A key feature is the lack of evolutionary history between exotic predators and native organisms. This lack of shared evolutionary history can facilitate predator invasions both because potential predators might not attack invaders and because native prey might not show adaptive responses to invaders. If native prey exhibit weak antipredator responses to exotic predators (relative to their response to native predators), this shifts the balance of NCEs and CEs in explaining total predator impacts on prey. Relative to native predators, exotic predators should have stronger CEs and weaker NCEs. Here, I discuss how this might influence predator invasion success, invasion dynamics over space and time, predator impacts on prey and cascading effects of predators on lower trophic levels. Note that even when exotic predators have large overall impacts, some prey are typically not hit as hard. I discuss how the relative impacts of exotic predators on different prey might be explained by the sensory ecology of prey response to predators. Finally, if time permits, I will suggest some implications of the ecology of fear for managing invasions, and for biological control.

Key words: predator-prey interactions, invasion ecology, antipredator behavior