Forest fragmentation and associated edge effects have greater impact on some species than others. For primates, size, diet, and foraging behavior are important factors for predicting vulnerability to edge effects. Previous researchers have suggested that for some lemur taxa, adaptations to natural disturbances provide resilience to anthropogenic habitat fragmentation. Tree-fall canopy gaps are frequent natural disturbances for Varecia rubra (red ruffed) and Eulemur albifrons (white-fronted brown lemurs) in northeastern Madagascar, but V. rubra are considered more vulnerable to habitat degradation and fragmentation than E. albifrons. V. rubra are large bodied, canopy-dwelling, ripe fruit specialists; E. albifrons are smaller, general frugivore/folivores that range throughout the forest strata. This research sought to address how tree-fall canopy gaps affect foraging behavior of V. rubra and E. albifrons. We predicted that flexibility in diet and strata use of E. albifrons would result in this species having a greater affinity for foraging along gap edges than V. rubra. We conducted 100 hours of instantaneous, focal-animal sampling of each species during Sep-Oct 2017 in Masoala National Park, recording behavior and flagging location at each time sample. The day after behavioral observations, researchers returned to flagged locations to record plant phenology and distance to the nearest gap.
Results/Conclusions
Preliminary data suggest that the species interact with tree-fall canopy gaps differently. V. rubra foraged at a significantly larger mean distance to the nearest gap (M=9.6 m, SD=10.2) than E. albifrons (M=2.2 m, SD=3.4; (two sample t(117)=-7.18, p<0.001). Future analysis will compare lemurs’ mean distance to gaps with the mean distance of randomly sampled transect trees. In addition, we hope to address the impact of the distance to the nearest gap on phenology, food availability, and nutrition. Given the projected increase in both natural and anthropogenic disturbance in Madagascar and throughout the world, a better understanding of the interactions between disturbances, behavior, and ecology is essential for many species’ long-term survival. Such enlightenment will allow scientists to make better predictions regarding species’ vulnerability to extinction in the context of fragmentation and climate change. Conservationists can then apply these lessons to management plans of populations subject to edge effects.