Modeling Gray Wolf (Canis lupus) Habitat in the Pacific Northwest, U.S.A

Gray wolves (Canis lupus) were once widespread throughout most of North America including the Pacific Northwest. Wolves were extirpated from the Pacific Northwest in the early 20 century and have been absent for over 60 years. The success of reintroduction efforts in Idaho and the greater Yellowstone area, however, has caused wolf populations in these regions to rise dramatically, giving way to wolf dispersal into Oregon. This study used a Geographic Information System (GIS) and wolf pack locations from the Rocky Mountain region to model gray wolf habitat. A priori models were created under the hypotheses that wolf habitat (1) will include a relatively high prey density, (2) will be limited by human influence, (3) will include favorable landscape characteristics such as forest cover and public ownership, and (4) may be influenced by some combination of these factors. Logistic regression was used to select the best model for predicting wolf habitat. The resulting model was tested in Idaho, Montana, and Wyoming and applied to Oregon to reveal approximately 68,500 km of potential wolf habitat that could support a population of approximately 1450 wolves. The final model, which included variables of forest cover and public lands, was applied to the greater Pacific Northwest to identify possible locations for wolf colonization throughout the area. The model may be relevant for other parts of the world where wolf reintroductions are planned or recolonizations are taking place. In addition, the methods presented in our study may be applicable to other wide-ranging large carnivores in other regions.