JCJC - Jeunes chercheuses & jeunes chercheurs

Impact of climate change on terrestrial ectotherms – ECTOCLIM

Submission summary

Climate change is now clearly established and is predicted to accelerate in the next century. One essential prerequisite for developing sound predictions regarding the impact of global warming on biodiversity is to understand the proximate mechanisms by which species will respond to environmental changes. Among vertebrates, most studies on climate effects have focused on endotherms (birds and mammals). However, the vast majority of organisms are ectotherms and, as such, they have dramatically different life histories. Terrestrial ectotherms cannot produce heat and their body temperature is more sensitive to changes in ambient conditions. They are characterized by an extreme level of phenotypic plasticity and generally limited dispersion capacities. An increase in temperature will affect all aspects of their life cycle at different stages from embryonic development through growth to adult life. Terrestrial ectotherms are thus particularly important models to study the impact of climatic changes on biodiversity. According to the metabolic theory of ecology, metabolic rate constitutes a central biological parameter that provides a link between the individual, the population, and ecosystems (Brown et al. 2004). Metabolism determines the rate of most activities and controls growth, reproduction, and survival. In this context, identification of metabolic adaptation is a central tenet to predict species' sensitivity to climate change. The main goal of the project ECTOCLIM is to study the impact of changing ambient temperature on the metabolic rate of squamate reptiles (lizards and snakes). We will use a comparative approach considering closely related species that differ in their biogeographic and thermal affinities. Our main postulate is that climatic changes will entail contrasting effects, positively influencing activity and negatively affecting energy budget. In addition, we predict that climatic affinities and adaptation will determine adjustment capacities with reduced compensation capacity in northern climate adapted species. Compared to endotherms, reptiles show an extreme level of tolerance to body temperature variation. This physiological characteristic is an essential feature that permits to examine experimentally the effect of changing environmental condition. For instance, it is possible to impose contrasted thermal regimes on developing embryos or adults without inducing pathological effects. The most innovative aspect of ECTOCLIM is precisely to rely on an experimental approach to study the impact of global warming. Using climatic chambers, we will impose specific thermal conditions at different stages to quantify the impact of future climatic changes. ECTOCLIM is based on three complementary axes. First, we will test if biogeographic affinities are associated with contrasting metabolic adaptations by comparing metabolic reaction norms and acclimation capacities. Second, we will determine thermoregulatory needs of related species that have reacted differently to recent climate changes. Finally, using climatic chambers, we will impose on captive animals thermal regimes inspired from recent climatic manifestations (2003 heat wave) and projected climatic predictions from General Circulation Models (IPCC scenarios) to test the effects on fitness related traits. Combined, these experiments will provide great insight into the impact of anticipated climatic changes. This project will be conducted by three young researchers (O Lourdais, S Meylan CNRS UMR 7625, and G Blouin-Demers, University of Ottawa) with complementary interests and approaches. Olivier Lourdais will be the leader of the project and the recently created 'Evolutionary Ecophysiology' team at the CEBC will constitute an optimal working base.

Project coordination

Olivier LOURDAIS (Organisme de recherche)

The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.

Partner

Help of the ANR 200,000 euros
Beginning and duration of the scientific project: - 48 Months

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