Structure and spatial organization of an Amazonian terra firme forest primate community

Abstract

A high-diversity primate community consisting of 13 species was examined at an entirely undisturbed and remote terra firme forest near the headwaters of the Urucu River, Amazonas, Brazil. Twelve of these species used a 900-ha study plot, located 4 km or more inland from the river, and comprised a total group density of 16 groups km−2, an overall density of 146 individuals km−2, a crude community biomass of 381 kg km−2, and a metabolic biomass of 278 kg 0.75 km−2. These species were occasionally found together within small (≥1 km 2) areas of forest, so long as they included the full complement of available forest types. More frequently, however, only half the species co-occurred in a single habitat type at any one time, reflecting a relatively consistent pattern of subcommunity spatial organization. Habitat generalist species making extensive, yearround use of the predominant habitat type (high forest), were common, whereas habitat specialists were uncommon to very rare, and confined to minor habitats. Those species coexisting throughout the year in high forest were found to segregate vertically from one another. These and other modal patterns of community structure were disrupted seasonally by long-distance, inland movements by two ‘igapó’ forest species living in large groups – squirrel monkeys and white-face capuchins – to high forest areas, which apparently resulted from a food bottleneck in their habitat. Another species found in large groups – woolly monkeys – also exercised seasonally vagrant movements within the high forest matrix, which coincided with periods of greatest scarcity of mature fleshy fruits.