Habitat use by Callicebus coimbrai (Primates: Pitheciidae) and sympatric species in the fragmented landscape of the Atlantic Forest of southern Sergipe, Brazil

Anthropogenic habitat fragmentation is a chronic problem throughout the Brazilian Atlantic Forest biome. In the present study, four forest fragments of 60-120 ha were surveyed on a rural property in southern Sergipe, where two endangered primate species, Callicebus coimbrai Kobayashi &amp; Langguth, 1999 and Cebus xanthosternos Wied-Neuwied, 1826, are found. Two transects were established in each fragment, and the predominant habitat in 50 m sectors was assigned to one of three categories (mature forest, secondary forest and anthropogenic forest). Standard line transect surveys of the resident primate populations - which included a third species, Callitrhix jacchus Linnaeus, 1758 - were conducted, with a total of 476 km walked transect, resulting in 164 primate sightings. At each sighting of a primate, the habitat class was recorded and the height of the individual above the ground was estimated. The analysis indicated a significant (p < 0.05) preference for mature forest in C. xanthosternos which was also observed more frequently in the larger and better preserved fragments. No clear habitat preference was verified in the other two species, although both were relatively more abundant in the smaller fragments. However, a tendency to avoid anthropogenic forest was observed in C. coimbrai. Callitrhix jacchus used significantly lower (p < 0.05) forest strata than the other species, although other differences were unclear, presumably because of the reduced stature of the forest in the fragments. Overall, the results of the study indicate that C. xanthosternos is tolerant of the effects of habitat fragmentation, and that differential habitat use may play an important role in niche partitioning.