Abstract # 78:

Scheduled for Saturday, September 17, 2011 07:00 PM-09:00 PM: Session 14 (Salon G (Sixth Floor)) Poster Presentation


DENSITY-DEPENDENT DEMOGRAPHIC MODEL FOR THE FREE-RANGING CAYO SANTIAGO RHESUS MONKEY COLONY

R. Hern√°ndez-Pacheco1, T. M. Ruiz-Maldonado1, J. Gonsalez-Martinez2 and A. M. Sabat1
1University of Puerto Rico, Department of Biology , P.O. Box 23360 , San Juan, PR 00931-3360, USA, 2Caribbean Primate Research Center, University of Puerto Rico-Medical Sciences Campus
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Density-dependent population growth - the decrease in growth rate with an increase in population density - is considered less frequently in studies of field populations due to lack of adequate data to parameterize the models. This is of concern because density-independence assumptions may give rise to unrealistic population projections by overestimating demographic parameters leading to unsuccessful management plans. We developed a density-dependent model for Rhesus monkeys, Macaca mulatta, based on demographic data from the Cayo Santiago colony. Survival and fecundity of Rhesus monkeys from 1980 to 2009 were measured by following the fate of 1478 female monkeys through time. To test for density-dependence, fecundity was plotted against density data, and regression analysis was carried out. An age-based population projection matrix was constructed and analyzed. Negative density-dependence in fecundity rate was found. This was incorporated in the matrix equation, and the asymptotic population growth rate (?), the stable stage distribution (w), the reproductive value vector (v), and the elasticity matrices for every census period were calculated. The data showed a significant decline in fecundity, and a corresponding decline in ? with an increase in density. The model was able to explain 42% (R^2 = 0.42) of the observed variability in colony size between 1980 and 2009. We conclude that our model could be used to accurately improve culling strategies without risking the viability of the colony.