Managing animal movement conserves predator–prey dynamics

Abstract

Anthropogenic landscape change can lead to novel interactions among species with consequences for predator–prey dynamics. Population responses of predators and prey vary according to species abundance, movement, and distribution. Although conservation often involves managing species abundance, culling predators to benefit vulnerable prey is socially, ethically, and ecologically tenuous. We conducted a before–after control–impact experiment to test how well mitigations designed to disrupt animal movement reduce encounters between endangered caribou (Rangifer tarandus) and their predators in a human‐modified landscape. Using camera traps, we quantified coincident habitat use by predators and prey. By deploying obstacles to disrupt ease of movement on human developments, we reduced the ratio of wolf (Canis lupus)–caribou encounters by 85% and reduced the ratio of black bear (Ursus americanus)–caribou encounters by 60%, without removing predators. By managing animal movements that regulate predator–prey encounters, risk to endangered species can be reduced without the disruptive trophic effects caused by intensive carnivore removals.