The effects of keystone resources and landscape of fear in modulating the spatiotemporal use of paca (Cuniculus paca) in Brazilian Atlantic Forest

Paca (Cuniculus paca) is a medium-sized caviomorph rodent that plays an important role in the dynamics of plant and animal diversity in Neotropical forests. Despite being a generalist species, habitat use can be influenced by the availability of resources, cover, and shelter, but also by the landscape of fear. We investigated whether paca habitat use is mainly driven by resource availability and/or the landscape of fear in a spatiotemporal context in the Atlantic Forest montane of Brazil. We used camera traps and generalized least squares models to investigate the influence of lunar phases on the modulation of environmental factors in paca habitat use and the effects on the prey–predator activity pattern. The availability of food resources, specifically Juçara palm (Euterpe edulis) and Paraná pine (Araucaria angustifolia), was the best predictor to explain paca habitat use, regardless of moonlight. These threatened and dominant trees provide keystone resources for paca safely and efficiently in the study area. However, we found that moonlight can alter the importance of the effect of its main predator (Puma concolor), on the spatiotemporal use of the paca. The risk of predation has a greater impact on the paca's habitat use during phases of intense moonlight, and as an anti-predation strategy, the paca changes its activity pattern precisely during these periods. Although the conservation status of the paca is of least concern, our results have highlighted its important ecosystem role in Neotropical forests, interacting strongly with key and threatened species of the Atlantic Forest.