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High accuracy thermal study of one Vosges du Nord Natural Regional Park’s watershed: starting point of a climate changes diagnostic at the local scale

Étude thermique d’un bassin versant du Parc Naturel Régional des Vosges du Nord : une prémisse à l’évaluation du changement climatique à l’échelle locale

Abstract : The increase in global atmosphere temperature will probably lead to an increase in waterbodies and streams temperature. On waterbodies, the change in temperature may impact the duration and strength of the thermal stratification. In all lakes, and especially the small polymictic ones (cf; ponds), the stability of the stratification will increase and then step the oxygen depletion up in the deepest water and impact the lake ecosystem. The fish population in streams will probably be limited to species with high temperature tolerance in the future and then, reducing the biodiversity. Some critical values in temperature may be reached more frequently and then lead to a higher mortality in some fish communities as the Salmo trutta fario in our regions. Headwater region is the most sensitive and reactive environment to the global warming, when they host the highest biodiversity with plentiful of streams and ponds. A developed streams and waterbodies network has been instrumented in order to measure the temperature and dissolved oxygen variations on the Zinsel du Nord watershed (71 km²).8 streams have been implemented with 23 temperature data loggers and one pond with 5 mooring chains with a total of 35 thermometers, in order to measure the hourly temperature evolution over several years with a high spatial and temporal accuracy. The internal pond’s dynamic study including thermal stratifications, stability, mixing and heat content variations is correlated with the local meteorological conditions. Combined with the concentrated streams’ temperature analysis, the two indicators are a starting point for the knowledge of the climate change’s vulnerability of the territory at the local scale. the Regional Natural Park of Vosges du Nord gather all the needed elements for the study, with several headwater streams, ponds and wetlands and is located in one of the places where the temperature growth from 1971 to 2000 is the highest in France, according to Joly et al., 2010. The Northern Vosges Regional Nature Park’s Charta plans to involve stakeholders, environmental managers and inhabitants in the management of the rivers and ponds. The Park organizes a participative program including scientist, local population, Non-Governmental Organizations and communes. The goal is to make local and regional environmental studies more visible with common fieldwork and the involvement of the population with conference-culinary workshop to make population sensitive to the climate change.