Synthesizing theory and databases to advance a general framework for how warming affects trophic interactions
- Mary I. O'Connor
- Hamish S. Greig
|Working Group||9th—12th December 2012||Participant List|
|Working Group||3rd—7th June 2013||Participant List|
Environmental changes affect species by changing their physiology and thus activity rates and population growth rates. These rate changes affect trophic interactions among members of the community. Such higher-order, indirect effects are notoriously difficult to predict, leading to great uncertainty about how species abundance, food web structure and ecosystem function will respond to a changing climate. We will combine ecological theory, such as the Metabolic Theory of Ecology (MTE) and its descendants, with available databases to test predictions about how temperature affects species and their trophic interactions. First, we will test whether optimal performance temperatures correspond to mean environmental temperatures or instead to a timeaverage of the physiological response that incorporates variance in temperature, and second, whether thermal sensitivity varies with body size. We will develop theoretical models to predict how these two possibilities alter species’ interactions, and test these predictions using published data as well as empirical data from working group participants and results of warming experiments and observational studies. Our framework will help predict the response of food webs to warming across a range of habitats, which is critical for national and global efforts to understand how atmospheric changes affect biodiversity and ecosystem function. We will develop this framework by achieving three goals: 1) We will use key principles of physiological responses to temperature change to derive theoretical predictions for the sensitivity of individuals to warming based on body size and thermal tolerance traits, and then test these against data. 2) We will develop general theory to relate the effects of warming on individual performance to the strength and outcome of trophic interactions. 3) We will synthesize recent experiments that have warmed multi-trophic communities to test theory and revise our central principles and questions This project builds on work begun in June 2012 in a Canadian Institute for Ecology and Evolution (CIEE) funded working group. However, our CIEE funding is limited, and we cannot continue without additional support. This is not a resubmission.