Fig. 4. Southern Androy, Madagascar, as seen in a Landsat image from May 2000 (adapted from Bodin et al. 2005). The study area is defined by the rectangular box. The isolated forest patches are distinguished by the separate dark spots situated within the light gray matrix of cultivated land. Patch sizes range from 1 to 95 ha, and the patches are fairly evenly distributed in the landscape. Areas classified as source areas are marked in the western and northern parts of the studied area. The spatial structure of connectivity of the present landscape, including forest patches measuring 1 ha or larger, as expressed through the graph theoretical model is shown when the vagility of Lemur catta is set to 1000 m.