13 Mag. 2016 - Rosalie Bruel

Lakes vulnerability to climate change modulated by human local forcings: ongoing studies and future collaboration with ISE

Presenta: Rosalie Bruel

INRA, University of Savoie, UMR 0042 CARRTEL, Thonon-les-Bains, France

Despite the good regional coherence of lakes physical responses to climate change (e.g. warming of surface water), biological responses are highly variable at the regional scale. In other words, it is really difficult to predict what are going to be the consequences of climate change on lakes ecological communities. Our work aims at testing the hypothesis that local human activities modulate lake biological responses to climate warming. Our approach so far includes the reconstruction of long-term (1500 years) changes in Lake Geneva cladoceran communities (subfossil remains) to compare lacustrine ecological responses to atmospheric warming under both low (Medieval Warm Period; 950-1250) and strong local human pressures (post-eutrophication phase; since 1990's). We then want to attempt a meta-analysis including ~10 lakes in order to test whether or not there is a pattern of lake trajectory at the pan-alpine scale, and if there is one, to which parameter(s) it is linked. As a first step, we reconstructed the ecological trajectory of Lake Varese (150 years), and found that the system experienced two major and abrupt ecological transitions over the last century.

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