From steps to home ranges: How habitat disturbance influences the movement drivers of an arboreal primate

The persistence of animal populations in anthropogenic landscapes often depends on adjusting their foraging and movement strategies to environmental changes that involve energetic trade-offs. However, it remains unclear how ecological resilience translates into movement flexibility and which factors influence animal movement in modified environments. Howler monkeys (Alouatta spp.) are known to cope with significant anthropogenic pressure across their range. We examined how a gradient of habitat disturbance alters intrinsic traits of black howler monkeys (A. pigra) and extrinsic habitat characteristics, and how these factors, in turn, drive their movement. We monitored six groups of black howler monkeys in southeastern Mexico for 1 year, collecting data on movement, activity, diet, neighbouring-group presence, food availability and microclimate. We developed intrinsic and extrinsic models to identify the main drivers of movement across three spatiotemporal scales. Our results revealed scale-dependent responses to disturbance. At the smallest scale (5-min steps), movement probability increased with folivory levels and proximity to neighbouring groups but was significantly constrained by high temperatures. At the intermediate scale (daily paths), resource sparseness led to longer daily travel distances, while group crowding in isolated fragments increased path circuity, reducing travel efficiency. Finally, at the broadest scale (use of space), groups in highly disturbed sites exhibited up to 99% seasonal home range overlap, indicating spatial saturation and a lack of buffering capacity against environmental stochasticity. Our analyses show that while black howler monkeys exhibit behavioural flexibility, their capacity to cope with anthropogenic disturbance is limited by physiological and spatial constraints. As human activities continue to alter ecosystems, animals must adjust their strategies to navigate changing habitats and shifting resource availability; however, when environmental limits exceed an organism's inherent flexibility, populations may face an increased risk of local extinction.