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Recent range contraction of the endangered Pyrenean desman (Galemys pyrenaicus) in the French Pyrenees [email protected] Anaïs Charbonnel1,2,3, Laffaille2,4, Pascal Marjorie Biffi2,3, Frédéric Blanc1, Mélanie Némoz1, Laëtitia Buisson2,3 © A. Charbonnel Background • The effects of global change on semi-aquatic mammals is little known in spite of a large number of endangered species • Most Species Distribution Model (SDM) studies consider climate change alone but other components of global change can contribute to species range shifts • In SDM studies applied to freshwater taxa, the hydrology is frequently overlooked due to the lack of data at large spatial scale but fine resolution • Stream flow variables can be simulated using hydrological models, and then included in SDMs through an integrated modeling approach Research questions • Do hydrological variables explain the distribution of a semi-aquatic mammal at broad scale and fine resolution? • Do SDMs accounting for climate, land-use and hydrological changes that have occurred during the last 25 years predict accurately the species distribution shift? Material & methods Results • Biological model: the Pyrenean desman (Galemys pyrenaicus) − Increasingly endangered − Endemic to the Pyrenees and the Iberian Peninsula − Uses streams in mountainous regions − Lives in aquatic habitats and feed on aquatic invertebrates • Accurate simulation of hydrology both in time and space 140 Measured Mesuré Simulated Simulé 3/s) 3 Flow débit(m (m s) 120 100 Example of simulated and recorded stream flow at the measuring station “Pont de Rieulhes”, at a monthly time step. 80 60 40 Land use Assessment of the accuracy of the simulations Topography Climate 2011 2010 2009 2008 2007 2006 2005 © E. Delgado 2004 2002 • Simulation of stream flow: 2003 20 • Study area: French Pyrenees • Substantial climatic and hydrological changes over the last 25 years, but negligible land use change Examples of variables: Historical simulated flow (m3/s) Historical temperature (°C) Historical agricultural land (%) Soil type • Species Distribution Models: 140 15 0.01 1.6 Flow change (%) Field sampling 100 0 Temperature change (%) Agricultural land change (%) Environmental variables Faeces detection along 500-m river section (Corine Land Cover) 119 0 34 -49 3 Mean change: - 0.6 m3/s Mean % of change: - 12 % 100 0 -100 Mean change: - 0.33 % Mean change: + 0.5 °C Mean % of change: + 5 % © A. Charbonnel No detection Detection TEM (Carthage) Current: 2011 - 2013 1222 river sections RAI FLO SLO FOR AGR NAT OBS TRI POP URB Contribution of the environmental variables to the distribution of the Pyrenean Desman. (ROE & Geofla) Ensemble of SDMs (consensus approach) Historical variables Historical Current 0 (SWAT simulations) 10 20 30 40 Historical: 1985 -1992 637 river sections • Importance of climatic and hydrological variables Importance (CERFACS) Historical model Historical distribution • Climatic and hydrological changes have led to a decline in the probabilities of presence (cf. projected distribution) • The stronger range contraction modeled (cf. current distribution) suggests that climatic and hydrological changes are not the sole drivers -0.38 of this contraction Probability of presence 1.0 Historical sampling 0.5 0.0 Projected distribution Current variables Current sampling Current model Current distribution Mean: 0.70 Historical distribution Mean: 0.59 Projected distribution Mean: 0.32 Current distribution Conclusions • Coupling hydrological models with SDMs enables to account for the effect of hydrological changes on range shifts of freshwater species • Both climate and hydrology are important drivers of the Pyrenean desman distribution, suggesting that this species is sensitive to global change • Other factors (e.g. predation) may have contributed to the rapid range contraction of the species Contact details 1Conservatoire d’Espaces Naturels Midi-Pyrénées, 75 voie du TOEC - BP 57611 - 31076 Toulouse, France 2CNRS; UMR 5245; CNRS; EcoLab (Laboratoire Ecologie Fonctionnelle et Environnement); 31326 Castanet-Tolosan, France de Toulouse; INP, UPS; EcoLab (Laboratoire Ecologie Fonctionnelle et Environnement); 118 Route de Narbonne, 31062 Toulouse, France 4Université de Toulouse; INP, UPS; EcoLab (Laboratoire Ecologie Fonctionnelle et Environnement); ENSAT, Avenue de l’Agrobiopole, 31326 Castanet-Tolosan, France 3Université Acknowledgments Fédération Aude Claire, Fédération des Réserves Naturelles Catalanes, Office National des Forêts, Groupe de Recherche et d’Etudes pour la Gestion de l’Environnement, Office National de la Chasse et de la Faune Sauvage, Parc National des Pyrénées, Conservatoire d’Espaces Naturels Ariège, Conservatoire d’Espaces Naturels Aquitaine. A. Maire, S. Sauvage, J-M.Sanchez-Pérez and their students, F. D’Amico, J. Brown & M. Williams-Tripp.