Mesopredator release facilitates range expansion in fisher

摘要: Some central and eastern populations of fisher Pekania [Martes] pennanti are expanding their ranges following historic range contractions, while many western have yet to do so. We investigated whether benefiting from a mesopredator release reductions in carnivore predator communities. This hypothesis posits that local extinctions the largest predators ‘release’ direct predation competition, leading an increase abundance, expansion potentially shifts morphology ecological niche. Our comparison conservation status communities fishers across four geographic regions supports hypothesis, especially range. meta-analysis diet also suggests released may benefit by complementing diverse diets with more large-bodied prey species, whereas those specialized (e.g. northwestern populations) or small amounts within California) experienced little expansion. Further, measurements museum specimens suggest individuals evolved larger body size since time most contracted range, which help them hunt species expected be available absence carnivores. Collectively, these data support reduced community is contributing variation modern fishers' In addition harvest restrictions, habitat protection translocations, future plans should consider potential effects community, emphasizing need quantify mortality sources fisher–predator interactions.