Thursday, August 6, 2009 - 8:20 AM

SYMP 16-2: The Aleutian archipelago:  Addressing the functional importance of carnivory through variation in space and time

James A. Estes, University of California


Islands, because of their isolation and unique individual histories, can often provide powerful insights into the pattern and process of ecology and evolution. Field studies so designed to explore specific questions in particular areas are embodiments of the larger concept of the Ecology of Place. My colleagues and I have utilized these simple properties of islands to explore the ecological importance of mammalian carnivory.


In this talk I will provide a synoptic account of 36 years of research in the Aleutian archipelago that addresses the direct and indirect effects of 3 different predators and their prey:  sea otters and sea urchins; killer whales and coastal-living marine mammals; and arctic foxes and seabirds.  In each case, the predators reduce prey abundance by one to two orders of magnitude, in turn setting off a diverse array of indirect effects that permeate their respective interaction webs.  These indirect effects involve both top-down and bottom-up forcing processes, establishing in some cases important linkages across ecosystems.  Conspicuous landscape/seascape-level effects are an ultimate manifestation of mammalian carnivory.