The erosion of biological diversity pertains to the category of problems that are brought to the fore in ‘debated universes’. There are scientific controversies about their definition, import and possible solutions and they involve opposing economic interests and political strategies. A ‘convention’–commonly shared values, set of definitions, rules and norms–implying a compromise among various actors and groups is needed to define and enforce policies. The Convention on biological diversity can be seen as an attempt to define such a middle ground. The rights and policy orientations it promotes are however challenged by overlapping norms and rules enacted in other arenas, such as the WTO. The purpose of this paper is to take up a conventionalist stance on the complex international regime that governs biodiversity management and conservation policies.