The genetic structure of a mouse lemur living in a fragmented habitat in Northern Madagascar

Habitat loss and fragmentation are major threats to biodiversity worldwide. Madagascar is among the top biodiversity hotspots and in the past 100 years several species became endangered on the island as a consequence of anthropogenic activities. In this study, we assessed the levels of genetic diversity and variation of a population of mouse lemurs (Microcebus tavaratra) inhabiting the degraded forests of the Loky-Manambato region (Northern Madagascar). We used a panel of 15 microsatellite markers to genotype 149 individuals. Our aim was to understand if the elements contributing to the heterogeneity of the landscape, such as forest fragmentation, roads, rivers and open habitat, influence the genetic structure of this population. The results showed that geographic distance along with open habitat, vegetation type and, to some extent, the Manankolana River, seem to be the main factors responsible for M. tavaratra population structure in this region. We found that this species still maintains substantial levels of genetic diversity within each forest patch and at the overall population, with low genetic differentiation observed between patches. This seems to suggest that the still existing riparian forest network connecting the different forest patches in this region, facilitates dispersal and maintains high levels of gene flow. We highlight that special efforts targeting riparian forest maintenance and reforestation might be a good strategy to reduce the effect of habitat fragmentation on the genetic diversity of extant M. tavaratra populations.