Anthropogenic habitat disturbance and food availability affect the abundance of an endangered primate: a regional approach

Anthropogenic habitat disturbances are causing large-scale declines in animal abundance. For many species, information on the drivers of decline is lacking or restricted to single sites, despite calls for regional approaches. In this study, we determined the effect of different types of habitat disturbance (natural or anthropogenic) and ecological factors on Geoffroy’s spider monkey (Ateles geoffroyi) abundance using a regional approach. We selected this study species because of its high degree of social flexibility and its endangered status. We surveyed 4 sites in the Yucatan Peninsula and recorded the number of individual monkeys encountered along 72 line-transect segments each measuring 500 m. Habitat disturbance variables were obtained from open-access databases and included distance to roads, presence and number of hurricanes, forest loss, and presence of forest fires. Ecological factors were based on data collected during vegetation surveys and included number and basal area of feeding tree species, and canopy height. We ran generalized linear mixed models and found that monkey abundance was negatively affected by forest loss but positively affected by the basal area of feeding trees. We, therefore, suggest that a combination of anthropogenic and ecological factors affects spider monkey abundance. Spider monkey’s high degree of social flexibility may be a mechanism allowing them to adjust to changes in their environment when canopy connectivity is not lost. Our results provide policy and conservation decision makers with key information to develop regional conservation plans. Additionally, our methods can be used to identify the factors that affect the abundance of other mammal species.