14 January 2014The evaluation of ecosystems and biodiversity has become an important field of inquiry for economists. Although this development has been largely motivated by the search for arguments in favour of more ambitious conservation policies, both the methods and the meaning of the results continue to be controversial. This article aims to clarify the interests and limitations of this works, by revisiting a number of issues, such as the economic qualification of the services that human societies take from nature, the specificities of their contribution to human well-being, or the consequences of a valuation of biodiversity based on ecosystem services. We conclude with a discussion of the purposes of evaluations: improving public policies or creating new markets?