Abstract
Payments for environmental services aim at creating incentives to maintain and develop the benefits provided by nature. Beyond the apparent commodification of these services, the objective is to strengthen strategies directed at improving the relations between ecosystem functioning and the organization of human societies. What are the origins, the natures, the relevancies of these mechanisms? How do they function? What are the interests and the limits of such policy instruments? How can they be useful within strategies aimed at managing desertification issues?