Abstract
This thesis is a philosophical investigation within the field of nature conservation, focusing on flora conservation practices, and situated in the French mediterranean region. The theme of temporalities is its common thread. By its very name, the idea of conservation raises questions about human actions in relation to natural historicities: what does it mean to conserve that which is constantly evolving - be it populations, species or environments? This question intensifies in times of accelerating and intensifying climatic and global change: what then can it mean to conserve a nature that is changing so rapidly and so radically? Starting from this fundamental question, the thesis aims at identifying and elaborating a set of temporal figures present in the field of conservation, at different levels of analysis, in a "field philosophy" approach: the philosophical questioning is combined with the use of participant observations in protected areas, the study of contemporary scientific literature from major conservation journals, and history of sciences.The results of the investigation are presented in three parts. The first one exposes four pictures of the mediterranean region : four scientific visions, by authors of botanical geography, ecology, bioclimatology and biogeography from the XIXth and XXth centuries : Alphonse-Pyrame de Candolle, Charles Flahault, Louis Emberger and Pierre Quézel. It offers a cross-genealogy of the theme of the mediterranean region and of certain concepts of plant ecological sciences that remain important in the contemporary field of conservation. In contrast, the second part focuses on contemporary figures of ongoing conservation, under the signe of trouble. It takes singular cases of protected plants as starting points, from hich are deployed the questionnings, hesitations and difficulties of conservation practitionners. These questionings relate to management of protected areas, the knowledge of the protected areas and species, and the priorization among several populations in order to conserve. The third part of the thesis once again shifts the level of analysis. It distinguishes three biases, or three temporal attitudes, within conservation programs that explicitly address the issue of climate changes : an attitude of anticipation, an attitude of reactivation, and an attitude of consignment.