Résumé
Biodiversity offsetting (BO) claims to slow down biodiversity loss caused by development projects by generating ecological gains mainly through restoration activities conducted on land acquired to this effect. This leads to social conflicts around accessing land, especially with farmers and other land-users. The purpose of this paper is to analyze the opportunities and challenges of implementing BO by involving farmers through contracts akin to agri-environmental or stewardship schemes to produce ecological gains. We call them Agri-environmental Biodiversity Offsets Schemes (ABOS) and conduct an empirical analysis of a large ABOS program implemented for a new railway line in Southern France. We examine the effectiveness of ABOS through a survey carried out with 145 farmers and find that the main determinants of ABOS acceptability are: i) socio-economic factors, ii) social norms, iii) trust with contracting institutions, and iv) ease of integration in farm activities. Although ABOS allow developers to meet their legal requirements, major concerns are raised about additionality, especially through the manifestation of windfall effects, long-term permanence, and non-compliance with contract requirements. We conclude with policy recommendations and research perspectives to improve the implementation of ABOS for both nature and people.