Monitoring Impacts of Natural Resource Extraction on Lemurs of the Masoala Peninsula, Madagascar

Abstract

"Monitoring the influence of human actions on flagship species is an important part of conserving biodiversity, because the information gained is crucial for the development and adaptation of conservation management plans. On the Masoala Peninsula in Madagascar, we are monitoring the two largest prosimian species, Eulemur fulvus albifrons and Varecia variegata rubra, at disturbed and undisturbed forest sites to determine if extraction of forest resources has a significant impact on the population viability of these species. To test the sensitivity of lemur species to routine extraction of natural resources by local villagers, we compared population demography and density for both species across six study sites, using a new census technique. Three of the study sites were closer to villages and, therefore, were more impacted by resource extraction than the others. Our data on more than 600 individual primates suggest that the level of resource extraction did not significantly influence group size, fecundity, or density for either species over the two-year period of this study; however sex ratios in Eulemur were biased toward juvenile and adult females in more disturbed areas, suggesting that males may be emigrating from areas of less suitable habitat. Population densities at each site and estimates of population size across the entire peninsula were calculated and used to evaluate the design of a new park in the area, and to ensure that it will be large enough to support viable populations of these threatened primates. These estimates were calculated by obtaining the surface area of each study region from a geographic information system. Monitoring of these species continues in buffer zone areas of the park, where resource extraction is still permitted."