Midwest Fish & Wildlife Conference 2016

AUTHORS: Sean M. Sultaire, Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, Wisconsin 53706; Dr. Benjamin Zuckerberg, Department of Forest and Wildlife Ecology, University of Wisconsin-Madison;Dr. Jonathan N. Pauli, Department of Forest and Wildlife Ecology, University of Wisconsin-Madison

ABSTRACT: Habitat loss and climate change are recognized as two predominate threats to wildlife populations. Populations at the southern range boundary of a species distribution offer a unique opportunity to study the effects of both these stressors, because they are likely most sensitive to a changing climate and habitat is often patchy. Snowshoe hares Lepus americanus exist at their southern range limit in Wisconsin and detailed historical information needed to track the response of this boundary to environmental change is available from historical surveys. We performed snow-tracking surveys at 148 historical hare locations and 64 additional sites throughout central Wisconsin to determine hare presence. We detected snowshoe hares at only 29 historical sites, and 22 additional sites, and observed an average shift north of 28.5 km since 1980. We found that historical (circa 1980) snowshoe hare presence was best explained by the distribution of forest cover at that time period. Patterns of extinction between time periods were primarily driven by a reduction in snow cover duration, as opposed to the current distribution of forest cover or forest disturbance. In this respect, the distribution of snowshoe hares in Wisconsin has tracked the shifting paradigm of wildlife conservation. The historical range retraction was primarily driven by habitat, at that time when habitat loss was the most recognized threat by research biologists. More recently, however, as climate change has moved into the conservation spotlight, the range of snowshoe hares in Wisconsin has become increasingly limited by snow cover. Projections of future range show that snow cover loss will likely continue to drive this species’ range shift into the future, while future changes in forest cover will play a relatively small role.