Protected areas have based their legitimacy on scientific register. But today, the model of rational environmental management is critiziced. The public policies are characterized by an increasing participation of socio-economic actors. The new composition of the Scientific Council (CS) of the Regional Natural Park and the National Nature Reserve of Vercors appears as an example of these trends. Two cases of the SC, one on hunting deer and wild boar, the other on the protection of a bird, the hazel grouses, have been analyzed in this article. It helps to understand how this opening are translated into practices and negotiations or (re)definitions of expertise and knowledge to be taken into account for the management and finally, the definition of protected areas and nature conservation. These evolutions and resistances give a view of how experts are affected by deer, wild boar and hazel grouse that populate the Vercors.