Fruit production needed to maintain populations of woolly monkeys: Recommendations for reintroduction projects

Abstract

Woolly monkeys are threatened and reintroduction projects are an alternative for their conservation. However, there is little quantitative information suggesting the habitat traits needed to sustain populations. In this study, we first analyze the factors determining the abundance of woolly monkeys (Lagothrix spp.) and second, we suggest the minimum amount of fruit production able to maintain a population. Data was obtained from a literature review including 50 Neotropical sites, and we added new information from three more sites recently gathered in Colombian forests. We used simple and logistic regression models on two scales: large (i.e. all Neotropical sites), and medium (i.e. sites within their geographic range). On the large spatial scale, the abundance of woolly monkeys was positively related with annual rainfall, and plant species richness; and negatively associated with the number of dry months. On medium scales, we found that the most important variables explaining the abundance of woolly monkeys across scales was fruit production. The regression models suggest that at least 200–300 kg/ha.yr are necessary to support a population of woolly monkeys, and according to a logistic regression 400 kg/ha.yr are needed so surpass the 0.5 chance to have a population. In reintroduction projects, since it is difficult for new occupants to efficiently use the natural resources, we suggest that this amount of fruit should be aimed. As fruit production seems to be associated with high soil fertility (e.g. close to the Andean mountains), this region should be priority for conservation projects on this species.