Cévennes mountains and its piedmont are Mediterranean environments extending from 1700 meters summits to coastline. The climate is characterised by summer droughts that last several months and extreme rainfall events occurring in autumn and spring. Current climate predictions point to an intensification of these extremes events. To assess the impact of these changes, our scientific community have been deploying a wide range of measurements and experiments to monitor environmental variables. Rainfall and discharge times series are monitored since the 50’s; chemical, ecological and social parameters were gradually added to enhance the monitoring. The monitored ecosystems range from mountain pastures and forests in the Cévennes mountains to crops, scrubland, badlands, karst caves and urban environments in the piedmont. Under climate and global change, the Cévennes socio-ecosystems suffer from water scarcity and sometimes poor water quality. We are setting up socio-eco-hydrological observatories to monitor the adaptative evolution to these issues. This set up began 15 years ago with the study fo flash floods risk and matter transport risk awareness and human behaviours during and between hydroclimatic crises (HydroPop and HyMeX projects). The ongoing socio-eco-hydrological monitoring is co-constructed with citizens and local policymakers in order to use science to advise decision making toward durability and resilience. Most of our sites are part of OZCAR-RI and RZA LTER infrastructures. They are part of the upcoming eLTER platform P3M : Mediterranean Plain, Piedmont and Plateau. In addition to long-term monitoring, this sites are privileged supports to test new measurement techniques and build interdisciplinary and participatory research projects. We welcome collaborations and provide a local expertise to projects requiring sites in Mediterranean mountains.