The value of cooperation for biodiversity conservation policies[L'importance de la coopération dans les politiques de conservation de la biodiversité]

Collective schemes are promising tools for improving biodiversity conservation policies within rural landscapes. Yet, despite being at the core of their design, cooperation and its underlying mechanisms have seldom been addressed explicitly by the literature on the topic. Our paper addresses this gap in the case of the agglomeration bonus (AB), by assessing the benefits of landowners' cooperation in conserving biodiversity through ABs with varying degrees of "collectiveness" (i.e., differing in terms of the "rules" governing landowners' enrollment into the AB). Methodologically, we couple an ecological-economic model with a group formation game to endogenize both landowners' cooperation and conservation responses to ABs characterized by different landowner-level enrollment rules and plot-level payments. Solving the model numerically on fictitious landscapes, we show that larger groups conserve biodiversity more cost-effectively. Findings indicate that the "value of cooperation" – defined as the difference in biodiversity achieved through collective vs. individual responses to the same plot-level payments – amounts to between 10 and 45 percent. As it leads to the highest degree of cooperation, we show that "open-list ABs" are generally the most cost-effective schemes, followed by "closed-list ABs" (where, contrary to open-list ABs, landowners can exclude someone from the group), "individual ABs" (where "groups" are limited to one landowner), and, finally, standard homogeneous payments (where bonuses are null). These results stress the importance of the very design of collective schemes to boost the effectiveness of conservation policies.