Land degradation at landscape scale, i.e. the alteration of habitats by reducing their natural characteristics, is today considered as one of the major causes of biodiversity erosion in developed and developing countries, in addition to its impacts on the utilized agricultural land. Land degradation progresses at an alarming pace, both worldwide and in France. Thus, the European Commission has established an objective for Member States of bringing an end to artificialization by 2050.
In France, however the alleged objetive is to reduce the rate of land degradation, the national targets remain unspecific. Regulatory measures have been passed to better consider of the impact of developments on natural environments (“Grenelle” laws). The objective of densification and combating the urban sprawl have been included in urban planning procedures as well as in the ALUR law (law no. 2014-366 of March 24, 2014 for access to housing and a renovated urbanism). Yet the phenomenon remains insufficiently documented. It is generally viewed in terms of the mere “depletion” of agricultural lands and natural spaces by “concrete cities”. Analyses have shown that an area of agricultural and natural land equivalent to that of an average French department is depleted every ten years, but the consequences of the phenomenon on biodiversity are still poorly understood and less well identified than for agriculture.
Action against land degradation consists in particular of regulating urbanization and its impacts, and in applying the “avoid-reduce-offset” sequence (which is today enshrined in the new French biodiversity law). But this mainly applies to large projects. The effectiveness of this range of tools remains in question.
Marc Barra will provide a better understanding of the consequences of land degradation on biodiversity. Alice Colsaet will summarize her work on the dynamics of land use change and its apparent socio-economic causes. Yann Laurans will put all this into perspective and will coordinate the discussion to follow.