The sunburn effect: how much will climate change affect food webs?

The expected impact of climate change on ecosystems is a hot topic in contemporary ecology. Changing temperatures will strongly influence ectotherms, because their vital rates depend directly on the temperature of the surrounding environment. However, we have only limited understanding of the impact of climate change on biotic interactions, e.g. in food webs, although they can alleviate or magnify the direct effects of climate change on populations and communities.

To understand how climatic stress affects organisms and their interactions, we conducted laboratory experiments with dragonfly larvae and their zooplankton prey. We have shown that warming increases the appetite and movement of dragonfly larvae and thus increases prey mortality. At the same time, higher temperatures lead to higher metabolic demands of the predators, which should decrease their population growth rate and ultimately increase long-term stability and persistence of the entire food chain. We have also found that the dragonfly larvae can gradually adapt to other temperatures, such that acclimated and non-acclimated larvae interact differently with the prey. We liken to the observed effect to sunbathing in the spring sunshine: while gradually increased times in the sun can yield a decent tan, getting too much sun too early leads only to a sunburn.

Overall, our results indicate that the ability of individuals to adapt to changing temperatures during their lifetime can at least partly mitigate the expected negative impacts of climate change on populations, communities and entire ecosystems.

Sentis A., Morisson J., Boukal D.S. (2015) Thermal acclimation modulates the impacts of temperature and enrichment on trophic interaction strengths and population dynamics. Global Change Biology: Published online 19 May 2015

http://onlinelibrary.wiley.com/doi/10.1111/gcb.12931/abstract