Laliberte, Andrea S. and William J. Ripple. 2004. Range contractions of North American carnivores and ungulates. BioScience 54(2):123-138.
RELEVANT TO: |
WILDLIFE |
HISTORICAL REFERENCE CONDITIONS |
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MANAGEMENT |
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DESCRIPTION OF DOCUMENT
The article examines the historic and current geographical ranges of 43 North American carnivores and ungulates to identify large-scale patterns in range contractions and expansions. Few quantitative studies have assessed the degree of human influence on species on a continental or global scale. This knowledge is crucial to effectively manage declining species, design reserves, and predict future contractions or expansions.
The study area included Canada, the U.S., and Mexico. The source utilized for historic ranges was The Mammals of North America, by Hall and Kelson (1959). Current species ranges were taken from The Smithsonian Book of North American Mammals, by Wilson and Ruff (1999) and Mammals of North America (Kays and Wilson 2002).
MAJOR FINDINGS
- 17 of the species have experienced range contractions (See Table 2).
- Species richness has decreased where human influence has increased (See Figure 4).
- Species losses were greatest for the temperate grassland, savanna, and shrubland biomes.
- Those carnivore species that were less affected by human influence are generalists (e.g. skunks)
- Species contractions are a major result of Euro-American settlement and postsettlement development in North America.
QUESTIONS RAISED FOR THE FORESTS
1) Are forest management strategies ensuring protection to those species whose ranges are declining in the face of current human influence? For example: cougar, bobcat, mule deer
2) What steps can be taken to help reduce the rate of range contraction within each forest?
FOREST MANAGEMENT SIGNIFICANCE
From this study, we conclude the type and amount of human activity and land use in each forest must be of priortiy if sensitive species and carnivore specialists are to sustain viable populations. Recommendations include:
- reducing livestock grazing, fragmentation by roads, and other human land use activities in areas that are used by species senstive to such disturbance.
- controlling ORV and other recreation uses through permit use and appropriate closures to provide relief to struggling species.
- monitoring activities that have been associated in the scientific literature with adverse population effects on native carnivores, ungulates, and other species.