A ecologia do forrageamento do muriqui-do-norte (Brachyteles hypoxanthus Kuhl, 1820)

Mourthe, Italo

Abstract

The northern muriqui (Brachyteles hypoxanthus) is the largest neotropical primate, largest terrestrial Brazilian endemic mammal and is considered to be one of the 25 most critically endangered primate taxa in the world. Currently, fewer than 1000 individuals are estimated to survive in some isolated fragments of Atlantic forest in the states of Minas Gerais, Espírito Santo and southern Bahia. In this study, I investigate the relationship between the size of foraging parties and environmental variables such as the size, quality, and spatial and temporal distribution of their preferred food sources. The capacity of animals to adapt their foraging party size to such environmental variables has been a central focus of several models of primate socioecology. The adaptive capacity of a group of 45-52 northern muriquis was assessed during a fifteen month study in a semidecidual Atlantic Forest fragment, the RPPN Feliciano Miguel Abdala/Estação Biológica de Caratinga (19º42’50’’ S; 41º49’30’’ W). The study group was followed from dawn until dusk and individuals could be easily recognized due to irregular pigmentation in their faces and genitals. Feeding bout focal sampling (FBFS) were identified opportunistically as the first individual entered and began feeding in a food patch. The identity of each muriqui, the time it entered and departed the patch, and the type and identification of the consumed item were recorded. The study group showed a great flexibility on grouping at this site. Feeding aggregates were larger during wet season. The size of feeding aggregates and time spent feeding were correlated with tree size and muriquis shown preference for larger trees (DBH > 21 cm), independently of availability of this trees in the forest. Individual time spending feeding did not vary among trees of different sizes. The within-patch density of resources of an important species, Mabea fistulifera, which the muriquis exploit for its nectar, a high-energy food, was also an important variable in muriquis’ foraging strategies. This species is a common pioneer species, found on the hilltops of the study area. In addition to the FBFS data, the number of inflorescences consumed in Mabea trees was also recorded. The availability of productive inflorescence was determined with direct counts from trees immediately after the muriquis left these patches. The number of inflorescences used was correlated with tree size and number of inflorescences produced. Nectar consumption rates diminished significantly over time, indicating depletion of feeding trees. The mean number of inflorescences produced per tree was larger during the time muriquis were relying on nectar than subsequently. The insights into muriqui diet and foraging patterns that this study yielded are important to their conservation and management, especially in the disturbed and fragmented forests that this and many other populations inhabit.

• Thesis Type: Dissertation
• Deposit Date: Mar 19, 2024
• Keywords: aggregate size, foraging strategies, feeding tree size, within-patch density, northern muriqui.
• Award Date: Sep 4, 2006