Effects of differential habitat warming on complex communities.
Food webs unfold across a mosaic of micro and macro habitats, with each habitat coupled by mobile consumers that behave in response to local environmental conditions. Despite this fundamental characteristic of nature, research on how climate change will affect whole ecosystems has overlooked (i) that climate warming will generally affect habitats differently and (ii) that mobile consumers may respond to this differential change in a manner that may fundamentally alter the energy pathways that sustain ecosystems. This reasoning suggests a powerful, but largely unexplored, avenue for studying the impacts of climate change on ecosystem functioning. Here, we use lake ecosystems to show that predictable behavioral adjustments to local temperature differentials govern a fundamental structural shift across 54 food webs. Data show that the trophic pathways from basal resources to a cold-adapted predator shift toward greater reliance on a cold-water refuge habitat, and food chain length increases, as air temperatures rise. Notably, cold-adapted predator behavior may substantially drive this decoupling effect across the climatic range in our study independent of warmer-adapted species responses (for example, changes in near-shore species abundance and predator absence). Such modifications reflect a flexible food web architecture that requires more attention from climate change research. The trophic pathway restructuring documented here is expected to alter biomass accumulation, through the regulation of energy fluxes to predators, and thus potentially threatens ecosystem sustainability in times of rapid environmental change.
Department of Integrative Biology, University of Guelph, Guelph, ON, Canada N1G 2W1; ttunney@gmail.com.
Tyler D
TD
Tunney
Department of Integrative Biology, University of Guelph, Guelph, ON, Canada N1G 2W1;
Kevin S
KS
McCann
Harkness Laboratory of Fisheries Research, Aquatic Research and Monitoring Section, Ontario Ministry of Natural Resources, Peterborough, ON, Canada K9J 7B8; andDepartment of Ecology and Evolution, University of Toronto, Toronto, ON, Canada M5S 3G5.
Nigel P
NP
Lester
Harkness Laboratory of Fisheries Research, Aquatic Research and Monitoring Section, Ontario Ministry of Natural Resources, Peterborough, ON, Canada K9J 7B8; andDepartment of Ecology and Evolution, University of Toronto, Toronto, ON, Canada M5S 3G5.
Brian J
http://orcid.org/0000-0002-3733-6005
BJ
Shuter
D000818:Animals; D001833:Body Temperature Regulation / Q000502:physiology; D002980:Climate; D017753:Ecosystem; D020387:Food Chain; D056145:Freshwater Biology / Q000379:methods; D057232:Global Warming; D060106:Lakes; D008962:Models, Theoretical; D010839:Phytoplankton / Q000254:growth & development; D013696:Temperature; D014337:Trout / Q000254:growth & development* / Q000502:physiology
habitat coupling; heterogeneity; species interactions; thermoregulation; trophic structure