Fear of humans mediates spatiotemporal interactions between endangered large Asian felids

Species competitive interactions influence carnivore demography. Humans, as global 'super predators,' may mediate interactions among sympatric carnivores, although the effects of ecological fear on these interactions remain less understood. We used two years of camera trap data from more than 300 sites in northeast China to fit two-species, dynamic occupancy models. We then assessed how direct human passage affects spatial and temporal interactions between tigers and leopards, and the consequences for predator‒prey overlap in a temperate forest. We found evidence that median site occupancy, colonization and detection of leopards were lower at sites where tigers were present than at sites where tigers were absent. The effect of tigers on leopards in both space and time varied with disturbances. Leopards and tigers co-occurred less often than would be expected by chance at sites where human activity was greater. Tigers, but not leopards, significantly shifted their activity towards increased nocturnality in response to predominantly diurnal humans. This resulted in a decrease in temporal overlap among the two top predators and predator-ungulate prey at more disturbed sites, most notably between the tiger and prey (but no decrease in spatial overlap). Leopards appear to avoid tigers through time or space in areas where encounter risks are increased; in particular, leopards shift their core activity range as a main strategy to cope with dominant tiger and human activity across the sites. These results reveal that the human-induced landscape of fear may modify the strength of intraguild interactions between apex felids and structure food webs in a shared ecosystem. Furthermore, we highlight the importance of considering the pervasive risk introduced by a dynamic human presence to better understand the adaptive strategies used by competing top predators to mitigate threats.