Habitat Selection by Recolonizing Wolves in the Northern Rocky Mountains of the United States

Abstract

Gray wolf (Canis lupus) populations have persisted and expanded in northwest Montana since 1986, while reintroduction efforts in Idaho and Yellowstone have further bolstered the regional population. However, rigorous analysis of either the availability of wolf habitat in the entire region, or the specific habitat requirements of local wolves, has yet to be conducted. We examined wolf‐habitat relationships in the northern Rocky Mountains of the U.S. by relating landscape/habitat features found within wolf pack home ranges (n = 56) to those found in adjacent non‐occupied areas (n = 56). Logistic regression revealed that increased forest cover, lower human population density, higher elk density, and lower sheep density were the primary factors related to wolf occupation. Similar factors promoted wolf pack persistence. Further, our analysis indicated that relatively large tracts of suitable habitat remain unoccupied in the Rocky Mountains, suggesting that wolf populations likely will continue to increase in the region. Analysis of the habitat linkage between the 3 main wolf recovery areas indicates that populations in central Idaho and northwest Montana have higher connectivity than either of the 2 recovery areas to the Greater Yellowstone recovery area. Thus, for the northern Rocky Mountains to function as a metapopulation for wolves, it will be necessary that dispersal corridors to the Yellowstone ecosystem be established and conserved.

Wolf, <em>Canis lupus</em>, Den Site Selection in the Rocky Mountains

“…Stephenson (1974*) found a much steeper average slope of 33 degrees in the Brooks Range of Alaska. Using elevation and slope measured in a GIS model, Oakleaf (2002) found core areas of pack home ranges in the northern Rocky Mountains at lower elevations with gentler slopes. Although we found that most dens were located within home range core areas, we found no significant correlation between den sites and elevation or slope.…”

“…We selected six variables that previous literature suggested were important in habitat selection by Wolves (Matteson 1992;Mladenoff et al 1995;Oakleaf 2002) and that could be generated in ArcView from existing data layers (Table 2).…”

“…We used 15 April in this model as an average date for parturition in the northern Rocky Mountains (C. Mack, personal communication). Because Wolf home ranges and dens in the northern Rocky Mountains have been found primarily in coniferous forests (Matteson 1992;Oakleaf 2002), a coniferous forest GIS layer was derived from National Land Cover Data. This data layer was developed from 30 m resolution as a percentage of forested cells within 100 m of den and contrast site.…”

Fragmentation, dispersal and metapopulation function in remnant populations of endangered mountain caribou

“…Wolves, on the other hand, disperse widely (Fritts, 1983;Lehman et al 1992;Forbes & Boyd, 1997), possibly an adaptation to avoid inbreeding as unlike bears or caribou, wolves are territorial. This dispersal ability has allowed wolves to recolonize many patches of suitable habitat across western North America where they had been eliminated by predator control (Hayes & Gunson, 1995;Oakleaf et al, 2006).…”

Interactions of wolves, mountain caribou and an increased moose-hunting quota --- Primary-prey management as an approach to caribou recovery.

“…In advance of developing RSF models for wolves, we assembled Geographic Information Systems (GIS) layers of landscape characteristics ( Table 2.1) that we hypothesized would influence wolf selection based on previous wolf-selection studies (Arjo and Pletscher 2004, Kuzyk et al 2004, Oakleaf et al 2006, Milakovic et al 2011. We classified the landscape into vegetation classes using multispectral images from SPOT 4/5 satellites (available at www.geobase.ca).…”