Practices, predators, preys, common voles outbreak and biodiversity

In the context of the great socio-economic, technological and environmental upheavals of agricultural revolutions, mountain areas are often considered as favorable to biodiversity and environmentally friendly agricultural practices. However, these territories are under real anthropic pressure via agriculture or forestry leading to one of the fundamental questions of the coming century on the alteration of natural resources, not human activities. These new farming systems have led to the emergence or increase in abundance of species that have become agricultural pests. Due to loss of food production, chemical control and damage to non-target fauna, reservoirs of zoonoses they represent or as an essential link in food webs, micro-mammals and their outbreaks represent an area of study of primary importance in ecology. Agricultural policies that have led to a specialization of agricultural practices towards grassland production have contributed to the emergence of outbreaks of prairie voles (ground vole and field vole) through increased crop production and homogenization of the agricultural landscape. in the Jurassic Massif and the Massif Central. While some predators like small mustelids specialize in the consumption of these micro-mammals. Other predators, considered as generalists, present a functional food response by adapting their diet to the availability of the resource. This functional response may be at the origin of a postponement of predation on prey alternatives to micro-mammals. Of all these species, hunting and heritage small-scale wildlife presently represent marked management and conservation issues. The purpose of this thesis is to compare two geographical zones (Upper Romans valley and Upper Jurassic mountains) with a priori different degree of knowledge about prairie volcano outbreak systems. Through this work, we compared the phenomenon of outbreaks observed in Haute-Romanche with current knowledge of the Jurassian Massif. We also, through the analysis of long-term monitoring data and the implementation of field experiments, tried to provide information on the relations between prey and predators in a meadow vole breeding system in a temperate environment. The objective is to try to make a comparison as much as possible between the two geographical areas to improve the management of these ecosystems. Our first work was to analyze the data collected between 1998 and 2010 to characterize the spatio-temporal functioning of the ground vole in Haute-Romanche. We also compared these data to the agricultural history of the valley between 1810 and 2003 at the plot scale. Firstly, we found that the agricultural historical scenario was similar between this valley of Haute-Romanche and other European mountain areas, with a specialization on grassland production and as a direct effect the virtual disappearance of plowed areas, the cantonment of mowing areas in the valley bottoms and extension of grazing areas to the rest of the areas used for agriculture. Based on these data, we were able to highlight a correlative link at the plot scale between the current land use and the intensity of the vole's overgrowth. Grazing areas had a lower vole abundance than mowed areas. The current agricultural occupation being directly dependent on the agricultural history of the valley, it seems likely that the agricultural specialization towards grassland production in this valley is, as in the Jura, the origin