Ecologia comportamental de Alouatta belzebul (Linnaeus, 1766) na Amazônia Oriental sob alteração antrópica de hábitat

Abstract

The behavioural ecology of two groups of red-handed howler monkeys (Alouatta belzbul) was monitored ou Gennoplasma island (Tucuruí, in the Brazilian state of Pará), between April and September 2004. The two study groups were of similar size and composition, but inhabited different forest types: native forest (group P) and a plantation of native tree species (group Q). Quantitative behavioural data were collected in three-minute scan samples conducted at ten-minute intervals. "AH events" sampling was used to record rare activities such as social and interspecific interactions. Resting was the predominant activity in both groups (P: 67.3%; Q: 61.9%), followed by feeding (P: 15.7%; Q: 21.4%), and locomotion (P: 15.8%; Q: 15.5%). The proportions of the first two categories were significantly different. The diet of both groups was folivorous-frugivorous, supplemented mainly by flowers. No significant seasonal variation was recorded in the diet of either group. The groups occupied home ranges of similar size (P: 5.25 ha; Q: 5.50 ha), although group P travelled 612 m ou average per day, as against 541 m for group Q. Both groups used preferentially their "original" habitat (group P: native forest; group Q: plantation), and the uppermost forest strata. Interspecific interactions were pacific, and social interactions were rare. The results of the present study present greater similarities with those of A. belzebul studies carried out in fragments of Atlantic Forest than at other Amazonian sites (continuous forest). This suggests that habitat disturbance may be a more important determinant of behaviour patterns than the characteristics of the biome. Overall, the results of the present study conicide with the typical Alouatta patterns of behaviour described in the literature.