Navegando por Assunto "Ateles marginatus"

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Acesso aberto (Open Access)
O coatá-de-testa-branca (Ateles marginatus) do baixo Rio Tapajós, Pará: distribuição, abundância e conservação
(Universidade Federal do Pará, 2001-02-16) RAVETTA, André Luís; FERRARI, Stephen Francis; http://lattes.cnpq.br/3447608036151352
The white-fronted spider monkey, Ateles marginatus, is an endangered species according to IUCN. Endemic to Brazilian Amazonia, its status is due to a combination of a relatively restricted geogaphic distribution and the growing human presence within this area. The present study focussed on the BR-163 (Santarém-Cuiabá) highway, on the right bank of the lower Rio Tapajós, a region of prolonged and intense human occupation. The principal aim of the present study was an evaluation of the distribution and abundance of A. marginatus within this area, and analysis of the factors determining these variables. Residents were interviewed informally at 16 sites in order to confirm the presence or absence of the species. Line transect population surveys were conducted at eight sites, representing differing degrees of habitat fragmentation, with a total transect length of 697.6 km. Groups of A. marginatus were monitored at two sites for the collection of data on their behaviour and ecology. The results indicate that the species is absent from some areas, including natural lacunae in its distribution as well as a zone of local extinction, that appears to extend as least as far as 60 km south of the city of Santarém. A total of 23 species of nonflying mammals were recorded in the population surveys, but the presence of A. marginatus was confirmed at only three sites. The study indicates that isolated fragments of forest of less than one hundred hectares are unable to support populations of A. marginatus. In the case of larger fragments, the presence and abundance of the species appears to be influenced more directly by human factors (hunting and logging). The species seems to be relatively rare even in continuous forest, which is similar to other populations of Ateles in Brazilian Amazonia. Two groups, one with eight members and the other with at least twenty, were identified during monitoring. As in other members of the genus, the formation of subgroups (fission-fusion), a relatively high proportion of females in the population and a frugivorous diet are also observed in A. marginatus. The study reveals the critical situation of the species in the region, in the face of human occupation, and the urgent need both to deter the process of habitat fragmentation and establish new protected areas.
Acesso aberto (Open Access)
Comportamento e dieta de um grupo de macacos-aranha-da-cara-branca, Ateles marginatus (É. Geoffroy, 1809), no sul da Amazônia
(Universidade Federal do Pará, 2014-12-17) SOARES, Paola Cardias; LOPES, Maria Aparecida; http://lattes.cnpq.br/3377799793942627
The distribution of precipitation over the months, influences on annual distribution of food resources and how these resources can be found in an environment causes primates to adopt different strategies in order to gain access to them. In our study, we evaluated the variations in behavior and diet of the white whiskered spider monkey (Ateles marginatus) at the Cristalino Private Reserve. The primates were followed and behavioral and diet data was systematically collected over nine months, between September 2011 until May 2012, through the scan sampling method. The variation concerning activity budget, use of space and diet was analyzed for three periods characterized by distinct rainfall amounts (early rains, rainfall peak and transition from rain to drought). At the peak of the rains, the primates apparently maximized its energy consumption, moving more (43.8%) so as to have more access to fruits, which were probably more available in the environment, eating more fruits (96.5%) and resting less (18.5%). Upper height classes (>20 to 30 meters) were most widely used during periods of rain, both at the beginning and in the peak, at least in part as a way to shelter from the rain and the ranging area and daily journey lengths were higher at the early rains period. There was a predominance of females in the subgroups, with males being more recorded (36.2%) at the beginning of the rainy season, probably to copulate, an activity that had most of their records occurring in one month (December) for that same period. Largest subgroups were recorded during periods of increased precipitation, and smaller sub-groups in drier times seem to be part of the strategy to avoid intraspecific competition. The diet was mostly frugivorous, being distinguished in the transition from rain to drought, not only by the lower contribution of ripe fruits (54.3%) as well as the contribution of young leaves (35.8%), when compared to the other two periods, when ripe fruits composed more than 70% of the diet. Diet diversity of ripe fruit was concentrated in a small number of key species of fruit trees and the fruits used to be swallowed whole, with the disposal of seed being unusual and occurring only for few species. Seeds ingested passed intact by the digestive tract of spider monkeys and caterpillars’ consumption was limited to a short period of time, constituting an alternative source of protein. Alternative items like decaying wood and earth from termite nests in months of low rainfall seem to complement the diet at the same time that also supply the primates’ diet with nutrients such as sodium, calcium and phosphorous, which are less present in ripe fruits, and the consumption of Eichhornia sp., although little recorded, suggests that these aquatic plants are important nutritional content in the diet of these primates. High frugivory of spider monkeys and their ability to disperse intact seeds away from the parent plants, reinforce its importance in the regeneration of forests and justify their conservation and their habitats. Information regarding the behavioral ecology and diet of these primates, though basic, are pioneering and essential to understand the adaptive strategies of the species.