Abstract # 119:

Scheduled for Sunday, September 18, 2011 11:00 AM-11:15 AM: Session 16 (Salon F (Sixth Floor)) Oral Presentation


GOLDEN-BACKED UACARI FORAGING ECOLOGY DYNAMICS: A CRITICAL TEST OF THE SEASONAL RESOURCE CONSTRAINT MODEL

A. Barnett, C. Ross and A. MacLarnon
Roehampton University, Centre for Research in Evolutionary Anthropology, London, England
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The golden-backed uacari (Cacajao ouakary: Pitheciidae) is a 3.5-4.5kg Neotropical primate from seasonally-flooded forests (igapó) of NW Amazonia. The social and foraging ecology of species has not previously been subject to detailed study. A study over 19-months provided the first concrete data on these aspects. As a strong diet and habitat specialist, with seasonal changes in group size and unusual features to its time budget, C. ouakary provides an interesting test of the seasonal resource constraint model of Terborgh & van Schaik (1987: as modified by Hemingway & Bynum, 2005) . This considers ranging flexibility, the relationships of diet flexibility with body size, morphology and food type availability, and of behavioral flexibility biogeographical peculiarities and resource seasonality, and makes nine predictions. The current study the study provided strong support for the predictions that habitat use will track resource availability, and that at the time of their use the availability of fallback foods will exceed that of items that annually dominate the diet. Weaker support was provided for the predictions that: ranging patterns will change when grain size of environmental heterogeneity exceeds species home range; fall-back foods of medium-sized primates would have low digestibility; morphologically specialized species will have narrow diet breadth. The current study did not support the prediction that frugivores lack diets with extensive temporal variation. Predictions relating to patterns of resource availability in Asia, Africa and South America could not be tested due to the absence of Cacajao-like primates outside the Neotropics. The cases of non-concordance are attributed to the highly unusual nature of igapo forests which forms the species’ main habitat. igapo has community-wide flood-choreographed pulses of leaf flush and fruit availability, which differ greatly from the resource availability patterns of the never-flooded rainforest for which the model was originally formulated.