S1-9 Thursday, Jan. 5 14:00 - 14:30 Searching for the biotic multipliers of climate change URBAN, Mark C.; Univ. of Connecticut email@example.com http://hydrodictyon.eeb.uconn.edu/people/urban/
Predictive models of biotic responses to climate change generally ignore species interactions. Yet, we know that species interactions often mediate climate change responses and extinctions. Understanding how climate affects all species and all of their interactions is impractical given the short time frame over which we need accurate forecasts. One solution is to identify key species that are both highly sensitive to climate change and that have disproportionately large effects on communities and ecosystems. These so-called ‘biotic multipliers’ provide the most bang for your buck in terms of spending limited research and conservation dollars. Evidence suggests that biotic multipliers often are top consumers. Top consumers often strongly affect communities and ecosystems through top down effects. However, why might they be more sensitive to climate change relative to lower trophic levels? Metabolic theory suggests one reason. Another hypothesis is that climate-induced food web effects at lower trophic levels combine in ways that increase sensitivity for top consumers. A third explanation is that demographic and life history traits shared by top consumers make them more sensitive to climatic change. Here, I update our knowledge of biotic multipliers and examine evidence for each of these hypotheses. I present several case studies that show how these mechanisms work in natural systems. Lastly, I present a prospectus for future research. This developing framework should help us to make better predictions so that we can mediate changes to biodiversity from climate change.