Human disturbance thresholds determine the ecological role of an apex predator.

The return of large carnivores to human-dominated landscapes complicates predator-prey dynamics. While predator and anthropogenic effects are well-documented in intact systems, their interplay in fragmented landscapes remains understudied. We examined whether apex predators still regulate prey and mesopredators in the large mammal community of the Golan Heights-a mosaic of nature reserves, farmland and military zones-where wolves (Canis lupus), golden jackals (Canis aureus) and wild boar (Sus scrofa) are culled to mitigate agricultural losses and human-wildlife conflict. Using 60 camera traps and high-resolution culling data, we quantified predator-prey and intraguild relationships, identifying land protection thresholds at which they shifted. We found that endangered mountain gazelles (Gazella gazella) were most active in protected areas (top 50% of sites) with higher wolf activity and consistently avoided jackals. Species-specific culling increased jackal activity but decreased boar activity in nonprotected areas (lower 65% and 62% of sites, respectively), outweighing the suppressive effects of wolves. While jackal culling modestly benefited gazelles in protected areas, the positive association between wolves and gazelles was sevenfold stronger. These findings suggest that apex predators may maintain their ecological roles in fragmented landscapes up to a threshold of human disturbance, beyond which top-down regulation weakens and ecosystem function deteriorates.