The Impacts of Habitat Fragmentation on the Golden-Brown Mouse Lemur (Microcebus ravelobensis) in the Mahamavo Forest Region, Madagascar

Abstract

Madagascar, home to some of the world’s most unique organisms, is suffering from heavy deforestation and habitat destruction. What little remains of the forest is highly fragmented, placing many species at risk. The endangered golden-brown mouse lemur (Microcebus ravelobensis) is among those in peril. Found only in the Mahamavo watershed, an area of 3,000 square kilometers, much of its remaining habitat falls on community lands and is experiencing rapid habitat fragmentation as land is cleared for grazing and agriculture. This study aims to determine what effects habitat fragmentation is having on M. ravelobensis and whether or not populations are able to persist in fragmented areas. Our study compared populations of M. ravelobensis in fragmented sites to those in continuous forests via capture-mark-recapture surveys. There were significantly fewer juveniles in forest fragments, indicative of a low reproductive rate. Additionally, males in fragments underwent unseasonal testes swelling, a response to environmental stress. Further, there was a difference in the capture locations of males and females, with females occurring farther away from the forest edges. M. ravelobensis densities also differed by site, with the lowest densities occurring in areas of high anthropogenic disturbance. Taken together, these results indicate that fragmentation in the Mahamavo region has led to changes in the population dynamics, reproduction, and spatial distribution of M. ravelobensis. Our research helps explain how habitat fragmentation is detrimental to golden-brown mouse lemurs and makes a case for the preservation of continuous forest in community lands.