Landscape ecology of lemurs in Madagascar

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A question of fundamental importance to ecology is understanding how plant and animal communities respond to deforestation processes (forest loss, forest fragmentation, and edge effects). Forests are becoming increasingly fragmented in many parts of the world, which result in edge habitats comprising a greater proportion of each fragment. For the lemurs of Madagascar, these issues are of particular ecological interest and conservation concern because humans have transformed most of the primary forests to grassland on the island. Although conceptual models have been developed to predict how animal communities will change due to forest loss and fragmentation, there are few empirical tests of the associated hypotheses on tropical mammals, let alone for arboreal primates, such as lemurs. My students and I propose to focus our research on the landscape ecology of two diurnal frugivores (Eulemur fulvus and Eulemur mongoz), one diurnal folivore/frugivore (Propithecus coquereli), two nocturnal folivores (Lepilemur edwardsi and Avahi occidentalis), and three nocturnal omnivores/frugivores (Microcebus ravelobensis, Microcebus murinus, and Cheirogaleus medius) at the fragment and landscape levels in and around Ankarafantsika National Park in northwest Madagascar. We will conduct our field research in six 3,000-4,000 ha fragmented forest landscapes. First, we will test hypotheses from species-area relationships, metapopulation models, and the species-fragmented area relationship to determine how landscape processes influence species richness. Species-area relationships predict that larger areas will contain more species. In metapopulation dynamics, patch occupancy reflects a dynamic relationship between extinction rates, which decrease with increasing area, and colonization rates, which decrease with increasing isolation. The newly proposed species-fragmented area relationship combines metapopulation dynamics with species-area relationships to predict how extinction risk influences species richness in highly fragmented landscapes.  Second, we will test an alternative hypothesis on how habitat amount influences species richness at the landscape level. This model holds that the number of species across sample fragments of the same size should increase with the total amount of habitat in the `local landscape' of each sample site, irrespective of extinction-colonization dynamics. The research that my students and I conduct is fundamental to a better understanding of the ecology of lemur populations in human-modified landscapes. Our research will also be amongst the first to collect and analyze data from primates at a landscape scale; most research has been on only a few groups of a species in and around one research site.