Innovative methods and organizational approaches to improving biodiversity offsets in France

Abstract

When development projects generate impacts on biodiversity that cannot be sufficiently avoided or reduced, offsets must be designed and implemented to effectively and fully compensate for the residual loss of biodiversity. International best practice indicates that biodiversity offsets must achieve no net loss of biodiversity, or preferably a net gain. How to design and implement such offsets remains a considerable technical and organizational challenge. Losses and gains must be assessed and compared, to demonstrate no net loss, in-kind and on the basis of targeted loss-gain metrics impacted for species, habitats, etc., offset feasibility must be assessed, to ensure they can land and expertise can be accessed for the implementation and long-term management. To address this challenge, a dedicated methodology was developed and applied to a new railway project in Southern France. Losses and gains were measured in "offset units", calculated as quality-hectares per species, and then integrated into a common framework to determine the amounts of each multi-species habitat that had to be restored (and how) to achieve no net loss. The method was successfully applied thanks to a continuous engagement with stakeholders, and was shown to enable a rigorous, transparent and participatory treatment of biodiversity impacts from development.