Competition between apex predators? Brown bears decrease wolf kill rate on two continents

摘要: Trophic interactions are a fundamental topic in ecology, but we know little about how competition between apex predators affects predation, the mechanism driving top-down forcing ecosystems. We used long-term datasets from Scandinavia (Europe) and Yellowstone National Park (North America) to evaluate grey wolf (Canis lupus) kill rate was affected by sympatric predator, brown bear (Ursus arctos). interval (i.e. number of days consecutive ungulate kills) as proxy rate. Although bears can monopolize kills, found no support either study system for common assumption that they cause wolves more often. On contrary, our results showed opposite effect. In Scandinavia, packs with killed less often than allopatric during both spring (after den emergence) summer. Similarly, presence at wolf-killed ungulates associated killing summer Yellowstone. The consistency two systems suggests actually reduces Our suggest influence predation on lower trophic levels may depend composition predator communities.