Pursuant to the adoption of the European Concil's 1995 Pan-European Strategy for Biological and Landscape Diversity, connectivity between natural spaces has become an increasingly important issue in European biodiversity conservation. In this frame France began, in 2007, creating an ecological network "Trame verte et bleue-TVB (Green and blue ways) designed as a tool for zoning planning agency. The construction of this network can be understood as a process of "ecologisation" in which the involvement of the diverse inhabitants and users of the territory raises question. More precisely, we show how different visions of the land that come from different ways of knowing - whether they are naturalistic or linked to other approaches to space - come into conflict in the process of identifying these networks. These knoweledge is necessarily incomplete, especialy when it concerns ordinary nature, and lay knoweledge can be particularly difficult to mobilize. We analyse the debates provoked by the connectivity modeling for a "Parc Regional Naturel" using cadastral data and naturalist data collected by local experts (naturalists, farmers, hunters, etc). This example of building an ecological infrastructure reveals the fondamental incompatibilities between data used by officials and lay knoweledge. It also highlighits the incompatibility of the different scales at which stakeolders perceive ecological connectivity and territory, in addition to questioning the reliability of the data used and the conditions of the data production, this study emphasizes the need to confront different types of knoweledge - qualitative or quantitative - at the intersection of ecological and socio-economic dynamics. Doing so is essential to having local actors involvement in the TVB.