Foraging by forest ants under experimental climatic warming: a test at two sites
Article first published online: 18 JAN 2013
© 2013 The Authors. Ecology and Evolution published by Blackwell Publishing Ltd.
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Ecology and Evolution
Volume 3, Issue 3, pages 482–491, March 2013
How to Cite
Ecology and Evolution 2013; 3(3): 482–491
- Issue published online: 11 MAR 2013
- Article first published online: 18 JAN 2013
- Manuscript Accepted: 12 DEC 2012
- Manuscript Revised: 11 DEC 2012
- Manuscript Received: 17 OCT 2012
- US Department of Energy. Grant Number: DE-FG02-08ER64510
- US National Science Foundation. Grant Number: 1136703
- DOE Climate Science Center Award
- NSF Career Award. Grant Number: 09533390
- Climate change;
- critical thermal maximum;
- thermal tolerance;
Climatic warming is altering the behavior of individuals and the composition of communities. However, recent studies have shown that the impact of warming on ectotherms varies geographically: species at warmer sites where environmental temperatures are closer to their upper critical thermal limits are more likely to be negatively impacted by warming than are species inhabiting relatively cooler sites. We used a large-scale experimental temperature manipulation to warm intact forest ant assemblages in the field and examine the impacts of chronic warming on foraging at a southern (North Carolina) and northern (Massachusetts) site in eastern North America. We examined the influence of temperature on the abundance and recruitment of foragers as well as the number of different species observed foraging. Finally, we examined the relationship between the mean temperature at which a species was found foraging and the critical thermal maximum temperature of that species, relating functional traits to behavior. We found that forager abundance and richness were related to the experimental increase in temperature at the southern site, but not the northern site. Additionally, individual species responded differently to temperature: some species foraged more under warmer conditions, whereas others foraged less. Importantly, these species-specific responses were related to functional traits of species (at least at the Duke Forest site). Species with higher critical thermal maxima had greater forager densities at higher temperatures than did species with lower critical thermal maxima. Our results indicate that while climatic warming may alter patterns of foraging activity in predictable ways, these shifts vary among species and between sites. More southerly sites and species with lower critical thermal maxima are likely to be at greater risk to ongoing climatic warming.