Résumé
Protected areas are the cornerstones of conservation policies worldwide. However, only few researches are led to analyse the way they emerge, except for criticising top-down governmental choices. Yet, the historical approach and strategic analysis of public policy building over the long term allows a better understanding of the stakes of action capacity of these policies. We therefore mobilize the advocacy coalition framework to show that protected areas creation is always due to coalitions of actors who belong to different professional fields and act at different scales but nevertheless share common stakes. On the basis of a comparative study in French and Brazilian Amazon, we show that if all coalitions for protected areas share a common objective of limited deforestation, they are still very different according to the type of conservation they promote (strict biodiversity conservation, population-based conservation or sustainable forest management). We also show that the ability of the coalitions to build efficient public policies is highly depending on internal factors (i.e. their ability to gather strategic resources) and on external factors (i.e. socio-political context and international pressure). Finally, the comparative analysis of coalitions pleading for the same type of protected areas in two different countries allows us to insist on the importance of qualitative embedded researches when it comes to understand why some protected areas have more chances to reach environmental effectiveness in one socio-political context than in another one.