Intended and unintended consequences of wolf restoration to Yellowstone and Isle Royale National Parks

Abstract

Abstract Wolves (Canis lupus), a once widely distributed species, were systematically removed from many temperate zone ecosystems due to conflicts with humans. A change in human attitudes and cultural norms has brought about a recovery in some suitable areas, yet reintroductions are still controversial. Two notable reintroduction areas in the United States were Yellowstone and Isle Royale National Parks. Both proposals caused polarization and debate. In Yellowstone opposition focused on outside the park effects, mainly wolves killing livestock and wild game also desired by human hunters. At Isle Royale, opposition was mostly about human interventions into nature and impairment of wilderness values contrary to the spirit of 1964 Wilderness Act. Both locations had periods in the 20th century with and without wolves and the presence of wolves had a dampening effect on ungulate population fluctuations. Most outcomes of reintroduction at Yellowstone were predicted as the Environmental Impact Statement written beforehand correctly predicted 78% of the 51 outcomes that were examined. Wolves were too recently reintroduced to Isle Royale to make similar comparisons, but we conclude that intervention is not contrary to the Wilderness Act, nor author Howard Zahniser's vision, partially because wolf reintroduction was a mitigation for human actions. Also, not intervening, or inaction, often perceived as safer, would have had more damaging impacts to ecosystem functioning.

Keywords

• national parks
• reintroduction
• restoration
• wilderness
• wolves