Warming Food Webs

Principal Investigator(s): 

Mary O'Connor and Hamish Greig

Synthesizing theory and databases to advance a general framework for
how warming affects trophic interactions


Ecosystems include many types of creatures, and each responds to a change in environmental temperature through changes in physiological and metabolic rates. Though the number of species in most ecosystems makes predicting the consequences of environmental change seem hopelessly complex, in fact some responses to warming may be predictable based on fundamental metabolic processes, the thermal history of that species, or its body size.

Using mathematical models and data on how temperature affects the performance of species of different sizes and histories, we will model how warming affects species linked to other species through their feeding relationships. This information will provide a basic framework for predicting how environmental warming will affect ecosystems, which is critical for national and global efforts to understand how atmospheric changes affect biodiversity and ecosystem function.

UPDATE: September 2013

Although increasing evidence suggests species and communities are responding to climate change, ecological theory remains insufficient to produce models that hold across species or can be used to derive quantitative predictions for how change in the physical environment affects the structure and function of communities. 

Our working group brought together empirical ecologists, ecological modellers and biomathematicians to advance the links between temperature, metabolic rates and the outcome of species interactions into a general framework relating temperature and food web structure. An explicit goal of our program was the integration of theoretical and empirical approaches to understanding the temperature-dependence of species’ interactions and food web structure. Such an integrated framework of theory and measurable parameters will allow projections of community responses to climate change based on general principles, rather than extrapolations of historical patterns or idiosyncratic aspects of particular taxa that often ignore key processes such as species interactions.

We hope that the developments arising from this group will provide a springboard for a new generation of climate change experiments that focus on testing and developing theoretically-grounded hypotheses, resulting in a more conceptual approach to climate change ecology. Key areas of our work group efforts include:

  1. Building physiological responses to temperature into theoretical predictions for the sensitivity of individuals to warming
  2. The development of general bioenergetic theory that relates the effects of warming on individual performance to the strength and outcome of trophic interactions
  3. Synthesizing theoretical predictions and empirical observations for how warming effects food webs

Products and Publications:

Vasseur, D.A., J.P. DeLong, B. Gilbert, H.S. Greig, C.D.G. Harley, K.S. McCann, V. Savage, T.D. Tunney, & M.I. O’Connor. Increased temperature variation poses a greater risk to species than climate warming. Procedings of the Royal Society Biology 2014 281: 20132612

Gilbert B., T.D. Tunney, K.S. McCann, J.P. DeLong, D.A. Vasseur, V. Savage, J. B. Shurin, A.I. Dell, B.T. Barton, C.D.G. Harley, H.M. Kharouba, P.Kratina, J.L. Blanchard, C. Clements, M. Winder, H.S. Greig, & M.I. O’Connor. A bioenergetic framework for the temperature dependence of trophic interaction strength. Submitted.

Symposium, 2013 Ecological Society of America Annual Meeting, Minnesota. Warming consumers and their prey: general  principles and applications for how temperature affects trophic interactions. Individual talks listed below. Further information and abstracts:

SYMP 18-1 Scaling relationships for the temperature-dependence of species performance. V. M. Savage

SYMP 18-2 Predicting responses to temperature variation: Ecology and evolution in trophic systems. D. A. Vasseur

SYMP 18-3 Trophic interactions and temperature change: Using interaction strength to predict stability and productivity. B, Gilbert.

SYMP 18-4 Linking theory and experiments: A meta-analysis of multi-trophic warming experiments. M. I. O'Connor et al.

SYMP 18-5 Warming up food webs: Implications for trophic energy transfer. M. Winder et al.

  SYMP 18-6 Tipping points in temperature-dependent food webs. K. S. McCann

More information about this project.

This work is supported by the National Center for Ecological Analysis and Synthesis, a Center funded by NSF (Grant #EF-0553768), the University of California, Santa Barbara, and the State of California. This NCEAS project built on developments from a previous Canadian Institute of Ecology and Evolution (CIEE)-funded working group “Thermal scaling and body size: the next frontier in climate change”.