Abstract: In marine systems, many of the spatial and temporal changes in predator numbers – both increases and decreases – are human-induced. These changes are occurring at scales ranging from global (e.g., introduction of non-native predator species to novel environments) to local (e.g., changes in predators’ abundances due to fishing, or conversely to new protection from fishing). Indirect effects (that is, not involving direct predation) are known to be important in structuring ecosystems. Changes in predation risk can lead to changes in the ways prey reproduce, feed, communicate, utilize space and time, and interact with both conspecifics and other species. Changes in predator size and number have been documented to affect their own behavior, including reproduction and diet breadth, and to indirectly influence the survival of young colonists to local habitats. Indirect effects such as these can be profoundly important in ecology and conservation, and understanding them is critical for improving ecosystem-based management.

Biography: Robert Warner is currently Research Professor of Marine Biology in the Department of Ecology, Evolution, and Marine Biology at the University of California, Santa Barbara. Upon completion of a BA degree in Zoology from the University of California, Berkeley, Dr. Warner received a Ph.D. degree (1973) from Scripps Institution of Oceanography, University of California, San Diego. After two years as a postdoctoral fellow at the Smithsonian Tropical Research Institute in Panama, he joined the faculty at UC Santa Barbara, where he has served as Chair of the Departments of Biological Sciences and of Ecology, Evolution, and Marine Biology. Dr. Warner’s work spans two areas of fish biology, with over 160 peer-reviewed publications. The first is the evolution of mating systems and life histories. Past topics include the evolution of sex change and other forms of hermaphroditism in animals, sexual selection and the development of secondary sexual characters, gamete allocation, the dynamics of parental care allocation, the economics of territorial defense, and social effects on life-history allocations. Warner’s second area of research is in population biology, concentrating mainly on the dynamics of recruitment in marine fishes. He is interested in what determines variability in recruitment, the extent to which recruitment determines subsequent population dynamics, and the degree to which local populations of fishes are self-seeding. This work is related to Warner’s recent studies about the efficacy of marine reserves. His research has been supported primarily by the National Science Foundation, the Packard Foundation, and the Moore Foundation.