Socioecologia de Muriquis-do-Norte (Brachyteles hypoxanthus) no Parque Estadual Serra do Brigadeiro, MG

• Autor(a) principal: Moreira, Leandro Santana
• Data de Publicação: 2008
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/2205
• topic: Muriquis-do-Norte; Nicho ecológico; Fenologia; Forrageamento; Brachyteles hypoxanthus; Ecological niche; Phenology; Feeding; CNPQ::CIENCIAS BIOLOGICAS::ECOLOGIA

According to the ecological niche concept, each species can only survive in a set of natural characteristics, although they can tolerate variation intervals in each environmental dimension. To understand the necessary niche for the survival of an organism, as well as the behavior strategies used by individuals or groups for their adjustment to environmental alterations, is essential for the determination of conservationist actions, especially in the case of threatened species. Muriquis (genus Brachyteles) are endemic to the central portion of the Brazilian Atlantic Forest. The indiscriminate exploration of this ecosystem since the discovery of Brazil, resulted in a high extinction risk for the muriquis. Northern muriquis (B. hypoxanthus) are in the category "Critically Endangered". This dissertation aimed: 1) to characterize the Serra do Brigadeiro State Park (PESB) as a habitat for a remaining population of northern muriquis; 2) to investigate two dimensions of the ecological niche of muriquis: the pattern of arboreal phenology and the basic structure of the forest (regarding the diameter and height of the trees); and 3) to investigate the feeding strategies employed during variations in the availability of food resources. During 2 years and 4 months, a group of muriquis living close to the Brigadeiro s Farm, north of PESB, was habituated and monitored. For 12 months, the method of scan sampling was used to obtain the behavioral data of this group. Totally, 1680 scan sessions were obtained (420 hours of observations). To evaluate the forest structure and phenology, and the availability of food resources, 800 trees were selected and measured, of which each month an average of 548 was monitored. Muriquis selected more big trees than would be expected according to size distribution of trees in the forest. The annual diet of the group was composed by 40.9% of fruits, 31.6% of ripe leaves, 9.6% of new leaves, 3.3% of shoots, 4.8% of flowers and floral buds, and 9.9% of other food. The phenology pattern of the area indicated a general absence of synchronized food production; only fruits and flowers presented synchronism in the abundance with which they were made available in the forest. The main feeding strategy used by muriquis in periods of shortage of preferential foods (fruits and flowers) was a diet flexibility. Females adjusted their diet to the availability of fruits, while males to the availability of floral food. In scarce times, both ate more leaves. In an annual base, males were more folivorous than females. Another significant strategy was the adjustment in the grouping pattern, in which females tolerated a higher number of neighbors at shorter distances during periods of a high consumption of fruits. Territorial strategies (adjustments in the daily travel distances and in the home ranges used) were not significant for the studied group, although it was observed an increase in the home range from the rainy to the dry season. PESB maintains a large remaining population of northern muriquis. The behavioral flexibility observed in this species, as well as the detailed dimensions of its niche evaluated here, allow us to draw strategies for the maintenance of this population and plans for management and restoration of other muriquis populations. The restoration of forest habitats for muriquis conservation should take into account the applications of this species as for the size of the trees, phenology patterns and food availability.