Impact of anthropogenic factors on occupancy and abundance of carnivorans in the Austral Atlantic forest

Global wildlife populations face multiple threats, from an ever-growing human population. The Carnivora, especially species of large body size are at risk of local extinction from habitat loss, as they depend on large home-ranges and are highly susceptible to changes in prey populations. The objective of this study was to detect responses of carnivorans of different body sizes to anthropogenic disturbance. Our hypothesis is that species groups will respond differently to anthropogenic factors, with larger bodied species predicted to show increased vulnerability to human disturbance. Camera-trapping was used in six areas of austral Atlantic Forest to detect carnivorans. Species were divided into five groups based on body size and carnivory level: i) apex (hypercarnivores > 60 kg), ii) large (hypercarnivores 10–60 kg), iii) mesopredators (hypercarnivores 3–10 kg), iv) mesocarnivores (omnivores of 3–10 kg), v) and small predators (hypercarnivores < 3 kg). Data on detections and non-detections were used to model abundances based on group occupancy to understand how carnivorans of different body sizes respond to anthropogenic land-use variables. Apex and large predators were found to display lower human disturbance tolerance compared with medium and small-bodied. Mesocarnivores and small predators increased in abundance in areas with higher anthropogenic influence, where larger predators were absent. Our study suggests that smaller-sized carnivores may be experiencing population release at the landscape level aided by human activity, and that large carnivoran conservation appears to be dependent on high quality protected areas, with low anthropogenic disturbance levels.