Assessing potential gray wolf restoration in the northeastern United States: A spatial prediction of favorable habitat and potential population levels

The northeastern United States was previously identified under the U.S. Endangered Species Act (ESA) as a potential location for restoration of a population of the endangered eastern timber wolf or gray wolf (Canis lupus). The gray wolf has been protected under the ESA since 1974. We used Geographic Information Systems (GIS) and a logistic regression model based on regional road abundance to estimate that the Northeastern states from Upstate New York to Maine contain >77,000 km(2) of habitat suitable for wolves. Using current habitat distribution and available ungulate prey (deer and moose), we estimate the area is capable of sustaining a population of approximately 1,312 wolves (90% CI = 816-1,809). This estimate is equivalent to new, much higher potentials estimated for northern Wisconsin and Upper Michigan, where wolves are rapidly recovering in the U.S. Midwest. Potential wolf densities vary from a low of <12/1,000 km(2) in the Adirondack Region of Upstate New York, where prey densities are lowest, to 20-25/1,000 km(2) in northern Maine and New Hampshire. A contiguous area of favorable habitat from Maine to northeastern Vermont (>53,500 km(2)) is capable of supporting approximately 1,070 wolves (90% CI = 702-1,439). Such large areas are increasingly rare and important for wolf recovery if populations large enough to have long-term evolutionary viability are to be maintained within the United States. However, large-scale restoration of a top carnivore like the wolf has other consequences for overall forest biodiversity in eastern forests because wolf recovery is dependent on high levels of ungulate prey, which in turn have other negative effects on the ecosystem. In the United States, planning for wolf restoration in the Northeast should take advantage of experience elsewhere, especially the upper Midwest.