Understanding predator-prey interactions is essential to the stewardship of ecosystems. For example, invasive predators cause widespread ecological problems, and other invasive species (plants, animals and microbes) may influence predator-prey interactions. Typically the ecological consequences of predators are envisioned as the direct effects of killing prey. Ecologists are, however, becoming increasingly aware of the importance of non-consumptive effects of predators, which result from prey behaviors to avoid being killed by predators. For example, when predator density increases, prey may change their use of habitat, hide more, and eat less. Behavioral responses to avoid predation are hypothesized to cost the prey's fitness and may affect the prey population as much as direct mortality from predation. These effects may then cascade to affect other species in the ecosystem. A number of short-term studies have demonstrated that such non-consumptive effects can affect prey growth rate and death rate in diverse ecosystems. This study is designed to scale up our understanding of non-consumptive effects in real communities on longer time scales, in order to investigate the influence of non-consumptive effects on prey abundance and ecological community structure. The investigators will use a combination of theoretical and experimental approaches based on a model fish-zooplankton community, to identify and elucidate non-consumptive effects of predators that are not predicted to arise from direct effects of predators killing prey.
Non-consumptive effects arise from a process common to all ecosystems and therefore this research will elucidate concepts and approaches that are of general relevance, thereby benefiting the management and stewardship of diverse ecosystems. In addition to supporting the research training and mentoring of two graduate students, this project will provide research experiences for a large number of undergraduate students. The project also involves outreach to present results to state agencies and citizen groups, and to develop demonstration modules on lake ecosystems and basic ecological concepts and issues for presentation to K-12 classrooms.
