Abstract # 1081 Event # 133:

Scheduled for Friday, August 19, 2005 04:30 PM-04:45 PM: Session 10 (Mayfair Room) Oral Presentation


FOREST FRAGMENTATION AND CHANGES IN THE FEEDING ECOLOGY OF BLACK HOWLER MONKEYS (Alouatta pigra) IN CALAKMUL, MEXICO

S. Calme and A. Rivera
ECOSUR, El Colegio de la Frontera Sur, Avenida Centenario Km. 5.5, Chetumal, Quintana Roo 77900, Mexico
line
     The rapid loss of habitat complicates the way monkeys deal with foraging in their environment. Here we report the results of a study on the feeding ecology of black howlers existing in habitats that differ in land use. Specifically we were interested in examining the effects of fragmentation on howlers’ diet and determining the basis for selection of feeding trees. The study was conducted in two sites within the Calakmul Biosphere Reserve (CBR) and in two remnant forests adjacent to the CBR. We used instantaneous scan-samplings of adult individuals every 15 minutes to record feeding habits, and we documented the species and plant part eaten. We measured diet selection using the Chesson selectivity index. Diet of black howlers inside CBR differed from the remnants in the number of tree species used for feeding (10 versus 16, respectively). Overall, only 50% of the species used for feeding were shared between CBR and the remnants. Inside CBR, 50% of feeding time was devoted to Ficus sp., which was absent in the remnants. Howlers were more selective in CBR than in the remnants: they selected 9 out of the 10 species consumed in CBR, and 12 out of 16 in the remnants. Our results suggest that black howlers showed a strong selection of particular elements of their diet and fragmentation tended to relax the degree of dietary specialization.