This article examines how sustainable development is actually being applied to rural development, and the assumptions about different forms of knowledge and their integration used in this application. The results of the study are based on a comparative analysis of research reports from 12 European countries on 27 projects and programmes for nature protection and biodiversity maintenance. It is argued that the distribution of different forms of knowledge and their evaluation are related to the form and structure of local civil society. The results suggest that the kinds of knowledge that are most prevalent in nature protection and biodiversity management are mainly scientific knowledge and, to limited degree, managerial knowledge, with the latter gaining in importance. In contrast, local knowledge as a knowledge system rooted in local resource use practices has become a rare feature of the European countryside.