Abstract
While the erosion of biodiversity accelerates dramatically, conservation planning techniques have been put forward as a solution for identifying priority areas for in situ conservation. This paper provides a short review of conservation planning history and methods, ranging from ad hoc approaches to Systematic Conservation Planning (SCP). SCP is aimed at defining explicitly an optimal and sustainable network of protected areas. This approach is illustrated through the case study of Réunion Island (Indian Ocean). The advantages and limitations of this method and the specific contribution of GIS and spatial modelling tools are specifically evaluated and discussed.