Abstract : The ZA PYGAR project aims at studying the spatial dynamics of socio-ecological systems (SES) in SouthWestern France, going from the Pyrenees mountains to the plains of the Garonne river basin. PYGAR tries to answer three main scientific questions: 1/ What are the respective contributions of climate change and local anthropogenic disturbances to ecosystem changes (biodiversity, bio-physical characteristics)? 2/ How human practices drive ecosystem services? 3/ What are the relationships between resources availability and their accessibility, and the historic and prehistoric human population structure? The main transversal question of PYGAR is the adaption and response time of the different SES to global changes. The SES are studied at different time scales from the last glacial maximum to the present-day. PYGAR clusters 17 Labs (40 full-time permanent staffs: 23 researchers/professors & 17 engineers/technicians) from Toulouse and Bordeaux, supported by the University of Toulouse and several French research organisms (CNRS, INRA, IRSTEA, IRD, CNES, BRGM, Météo France). Socioeconomic partners (companies, farmer's associations…) and public services (Occitania Region, Water Agency…) are strongly interested in the project. PYGAR includes 4 territories (sites ateliers): the central Pyrenees mountain range, the Garonne River, the agricultural hills and valleys of the Gascogne region and the Viaur-Aveyron river basin. The theory of SES provides a valuable tool to set up an interdisciplinary approach to deal with the co-evolution and resilience of the social and ecological templates of the studied systems facing global changes (climate change and land cover).
