Viable Populations for an Endangered Forest Primate, the Tana River Crested Mangabey ( <i>Cercocebus galeritus galeritus</i> )

Abstract

Abstract: Using genetic and demographic models we examined population viability for an endangered forest primate, the Tana River crested mangabey (Cercocebus galeritus galeritus). Estimates of effective population size (N e ) varied widely as a function of the initial size of the breeder population and the values used for male lifetime reproduction success. The least conservative estimates of N e suggest that the Tana mangabey is at risk of losing genetic variation. Demographic models also suggest that Tana mangabeys have a high probability of extinction over the next 50–100 years given their present population status. Results of both genetic and demographic models are similar: large populations are required. Given the mangabey's restricted range and severe habitat constraints, it would be an unrealistic management goal to strive for population numbers as great as those required by the models. The projections, however, allow us to compare ideal population sizes to real populations and to use the results as a guide to determine future actions necessary for conservation.