Quantitative approach to lakes ecological vulnerability to climate change

Session: Large Lakes’ Response to Climate: Past, Present, and Future (2)

Marie-Elodie Perga, IDYST, University of Lausanne, marie-elodie.perga@unil.ch
Aldo Marchetto, CNR-ISE, a.marchetto@ise.cnr.it
Pierre Sabatier, EDYTEM, University Savoie-Mont Blanc, Pierre.Sabatier@univ-smb.fr
Manuela Milan, IASMA Research and Innovation Centre, E. Mach Foundation , milan.manuela@gmail.com
Monica Tolotti, IASMA Research and Innovation Centre, E. Mach Foundation, monica.tolotti@fmach.it
Liisa Nevalainen, Faculty of Biological and Environmental Sciences, University of Helsinki, liisa.nevalainen@helsinki.fi
Nathalie Dubois, Geological Institute, Department of Earth Sciences, Swiss Federal Institute of Technology Zurich (ETHZ), nathalie.dubois@eawag.ch
Rosalie Bruel, University of Vermont, rosalie.bruel@uvm.edu

Abstract

Our objective is to quantify lakes vulnerability to climate warming, and to explain potential discrepancy of vulnerability among several systems. We worked on ten peri-alpine lakes (CH, FR, IT) with contrasted eutrophication histories in order to limit the variability of exposition to climate warming but maximise the variability of exposition to local human impacts. We reconstructed the ecological trajectory of these lakes for the past century resorting to palaeo-ecological tools. We selected Cladocera to represent the changes in ecological state and diatoms to reconstruct phosphorus levels. Then, we combined statistical tools to extract the quantity of variability due to climate warming.

We found contrasted levels of vulnerability to climate warming across the systems. Half of the variability was well explained by past levels of total phosphorus in the lake. At the peri-alpine scale, large lakes with an important history of eutrophication displayed more response, i.e. were less resistant, to climate warming.

Eutrophication has been and still is the major threats to surface freshwaters. Our results indicate that even after restoration, the lakes with strongest history of nutrient enrichment show the most responses to climate warming.

Twitter handle of presenter
@RosalieBruel