Abstract
Territory provides the support for interactions between humans avec their living environment. Among these interactions, it is well known that anthropic activities are a major cause of biodiversity erosion. In this respect, the mitigation hierarchy (avoidance, reduction and offsetting impacts) is a regulatory tool whose objective is to achieve a “no net loss” of biodiversity following urban development. However, the efficiency of the tool is questioned because of its practical and theoretical limits, and the recurring focus on biodiversity offsets and on the “project” scale, or the convergence of studies on large development projects.Based on questions arising from practical action and by adopting a multi-disciplinary approach and posture at the knowledge-action interface, this thesis hypothesizes that the current lack of efficiency is the result of a problem of scale and that a temporal, spatial and functional switch in scale could help the mitigation hierarchy to reach its objectives. Through quantitative and qualitative analysis of the mitigation hierarchy implementation for small-scale development projects, we identify a set of limits associated with studies done at scale of individual projects. These findings illustrate the need to upscale towards a territorial and strategic approach to the implementation of the mitigation hierarchy. Finally, we initiate a reflexion on the development of a methodological framework to anticipate the mitigation hierarchy implementation at the urban planning stage, and we test it on the Montpellier metropolitan territory.Finally, these research studies provide new answers to the question of the effective purpose of the tool: is its aim to avoid or legitimise biodiversity loss? Our propositions and perspectives for practitioners and scientists are in line with a mitigation hierarchy implementation that is more likely to reach no net loss objectives.