Exploring the Origins of Red Foxes (Vulpes vulpes) on Isle Royale

Abstract. Isle Royale National Park is generally considered a pristine ecosystem, but the island archipelago has a long history of human impacts that have altered the island's mammal communities through extirpations and introductions. The origin of red foxes (Vulpes vulpes) on the islands are of particular interest given their ubiquity and uncertain colonization history. Red foxes were first reported on Isle Royale in 1925, shortly after the foundation of a small fox farm that began on Isle Royale in 1922. We sequenced two mitochondrial haplotypes from red fox scats collected on Isle Royale and compared them to haplotypes from the mainland surrounding Lake Superior, the predominant source of the island's other native mammals. Some Isle Royale foxes matched widespread haplotypes commonly found across Canada, but over half of our samples matched haplotypes previously detected only in Newfoundland. While we cannot conclude a singular origin, we offer a working hypothesis red foxes on Isle Royale are derived from a combination of natural colonization and human introduction. Specifically, we propose native red foxes may be admixed with fur-farmed foxes from an introduction in the early 20th century.