THERMAL ADAPTATION OF DRAGONFLY POPULATIONS MEDIATES TOP-DOWN EFFECT ON STREAM ECOSYSTEM PROCESSES IN A GLOBAL WARMING CONTEXT
Predicting the consequences of climate warming on ecosystem processes is of major concern. To this regard, the response of dragonfly larvae as apex predators of litter detritivores may be crucial in altering the rate of organic carbon fluxes in streams. We hypothesised (1) such populations to be thermally adapted along a latitudinal gradient, which (2) mediates warming effects on prey abundances, leaf litter decomposition, periphyton biomass and CO2 concentrations. We tested if the respiration rate of larvae from Portugal, southwestern and northeastern France responded to the temperature gradient, i.e. with the three populations expressing different thermal performance curves for whole-organismal metabolic rate. Then, we tested if these populations subjected to three levels of experimental warming within a tri-trophic food chain induced different top-down effects on preys and ecosystem processes. Our results supported both hypotheses. We pointed out the occurrence of cold- and warm-adapted populations together with a warming effect on preys’ density and ecosystem processes being mediated by the origin of populations. In conclusion, considering population-specific rather than species-specific phenotypic traits appears essential when the objective is to quantify the impacts of organisms on ecosystems in a global warming context.
Thibaut Rota (Co-Presenter/Co-Author), EcoLab, Université de Toulouse, CNRS, France, firstname.lastname@example.org;
Antoine Lecerf (Co-Presenter/Co-Author), EcoLab, Université de Toulouse, CNRS, France, email@example.com;
Cristina Canhoto (Co-Presenter/Co-Author), Centre for Functional Ecology, University of Coimbra, Portugal, firstname.lastname@example.org;
François Guérold (Co-Presenter/Co-Author), LIEC, Université de Lorraine, CNRS, France, email@example.com;
Eric Chauvet (Primary Presenter/Author), EcoLab, Université de Toulouse, CNRS, France, firstname.lastname@example.org;