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Wildlife dispersal ability and landscape connectivity in the northern Rocky Mountains

Date: October 14, 2015


Background

The movement of black bears is strongly limited by roads.
The movement of black bears is strongly limited by roads.
Increasing human populations have fueled urban development and land conversion, causing substantial loss and fragmentation of wildlife habitat. In addition, climate change is expected to drive large-scale shifts in ecological conditions and geographic shifts in vegetation types.

New research is helping predict current and potential future patterns of fragmentation, prioritize keystone corridors for protection and enhancement, and identify which species in which places might require habitat restoration or assisted migration. This information will help natural resource managers, planners, and scientists maintain biodiversity across large landscapes.

Research Approach

Researchers evaluated conditions for 108 different species across a large portion of the Northern Rockies. The analysis used the universal corridor network simulator (UNICOR), a tool to predict habitat area, fragmentation, and corridor connectivity under current land use activities (Landguth et al. 2012). Information was compiled on biome-level habitat association, dispersal ability, and sensitivity to habitat fragmentation for the suite of species.

Researchers also evaluated the degree to which three carnivore species - American black bear (Ursus americanus), wolverine (Gulo gulo), and American marten (Martes americana) - function as a connectivity umbrella for species with more limited dispersal and different ecological characteristics.

Key Findings

Protected lands in the Northern Rockies are primarily higher elevation forest and mountain habitats. The scientists found high variation in the vulnerability of species because of the extent of connected habitat, and the extent

Extent of study area and predicted landscape resistance for movement of black bear, where dark areas are those low resistance ad light areas are those with high resistance. Red lines indicate major highways.
Extent of study area and predicted landscape resistance for movement of black bear, where dark areas are those low resistance ad light areas are those with high resistance. Red lines indicate major highways.
to which connected habitat overlapped protected lands. Species associated with high elevations have the vast majority of their connected habitat protected by Forest Service and National Park Service lands.

In contrast, species associated with lower elevations were poorly protected by the existing network of protected lands. Findings indicate that low elevation and non-forest habitats may be at highest risk of human-induced habitat loss and fragmentation.

This study also indicated that American marten, wolverine, and black bear are not the strongest candidates for umbrella species. American marten and wolverine are high elevation habitat specialists, and their patterns of habitat connectivity showed little overlap with that for other species. American black bear is a forest obligate and road sensitive species, so its connected habitat only overlapped with other species dependent on forest cover for movement.

Researchers believe that conservation efforts may be most effective if focused on expanding the network of lower elevation protected lands in such a way that maximizes connectivity across the landscape. These results provide a comprehensive evaluation of habitat connectivity to guide future restoration, conservation and mitigation strategies.

 

Featured Publications

Cushman, Samuel A. ; Landguth, Erin L. , 2012
Landguth, E. L. ; Hand, B. K. ; Glassy, J. ; Cushman, Samuel A. ; Sawaya, M. A. , 2012


Principal Investigators: 
External Partners: 
Erin L. Landguth, University of Montana (co-investigator)