The 82nd Annual Meeting of the American Association of Physical Anthropologists (2013)

Edge effects on body mass and habitat use in two sympatric species of mouse lemurs in a Madagascan tropical dry forest


Anthropology, University of Toronto

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Edge effects are an inevitable and important consequence of forest loss and fragmentation. These effects include changes in species biology and biogeography. Here we examine variations in body mass for two sympatric species of mouse lemurs (Microcebus murinus and M. ravelobensis) between edge and interior habitats in the dry deciduous forest at Ankarafantsika National Park. We anticipated that competitive exclusion would result in differing capture rates between species in edge and interior habitats. We predicted that the prevalence of Homopteran insects and their secretions, which represent a key food resource for local mouse lemurs, in edge habitats would result in higher body mass of mouse lemurs in these habitats. Between May and August 2012, we conducted mark-recapture experiments on mouse lemurs trapped along edge and interior forest transects within continuous forest adjacent to a large savanna near the Ampijoroa field station. Of the 37 M. murinus captured during our study, 78% (N=29) were trapped in interior habitats. Conversely, 75% (N=60) of M. ravelobensis were captured in edge habitats. We found that mean body mass of M. murinus and M. ravelobensis did not differ between edge and interior habitats. However, female M. ravelobensis weighed significantly more in edge habitats (56.6 ±10.4 g) than in interior habitats (48.1 ±11.7 g). We suggest that local resource competition combined with female dominance may have led to higher body mass in dominant animals in edge habitats. Our study provides some of the first evidence of sex differences in edge responses for a primate species.

This study was supported by a NSERC Grant to SML.

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