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New Report on Wolverines in Greater Yellowstone

Wolverines in the Greater Yellowstone Ecosystem can really move, they need a lot of room to roam, there are not very many of them in the large areas where they roam, and they tend to live in areas at or above treeline.  These are just a few results from this intensive study of 30 wolverines monitored from 2000 to 2008. 

What do the authors recommend we do for wolverines? They call for a refined wolverine habitat map for the western United States to help inform a metapopulation conservation and management strategy.

Here are a few more details...

 

Results

-          Male wolverine home ranges averaged nearly 800 km2 (>300 mi2), female home ranges averaged about 300 km2 (>100 mi2).  The vast majority of wolverine locations occurred in national forests (86%), but also occurred in national parks (12%), and on other lands (2%).

-          Male wolverines moved approximately 2-3 times farther than females.

-          Despite their large home ranges, wolverines traveled extensively throughout them on a regular basis.

-          Wolverine population densities were estimated at 3.5 wolverines per 1,000 km2 (>350 mi2)

 

Discussion excerpts

“For wolverines, an apparent tradeoff exists between resource acquisition on one hand and avoidance of predation and competition on the other.”

“… wolverine home ranges are 21-104 times larger than those of the coyote, badger and bobcat, 8 times that of lynx, and over 500 times that of the raccoon…”

“Our data… suggest that wolverines are capable of patrolling a large territory and provide further support for intra-sexual territoriality.”

“…our estimate of 3.5 wolverines /1,000 km2 is at the low end of reported values for North America and low relative to other carnivores in the GYE [Greater Yellowstone Ecosystem]… pre-1990 density estimates for the threatened Yellowstone grizzly bear… [were] approximately triple that of our estimates for wolverines.”*

“…this GYE scale is likely too small for a viable population.  A viable population may require an area as broad as the western United States…”

“Designing effective metapopulation conservation strategies would be greatly facilitated by development of an empirical prediction of wolverine habitat across the western United States, particularly one distinguishing among areas suitable for use by resident animals, reproductive females, and dispersal movements.  With this tool it would be possible for multiple management entities to conceptualize and collaboratively implement practices facilitating survival, reproduction and gene-flow at the most effective locations from the metapopulation perspective.”

* In an email exchange about the wolverine's low population density, Bob pointed out, "It is important to note that the density of wolverines 500 years ago may not have been very different at all from this level."

 

Link to a press release on the study by Wildlife Conservation Society

http://www.wcs.org/press/press-releases/yellowstone-wolverines-revealed.aspx

 

Citation and Link to the publication

Inman, Robert M., Mark L. Packila, Kristine H. Inman, Anthony J. McCue, Gary C. White, Jens Persson, Bryan C. Aber, Mark L. Orme, Kurt L. Alt, Steven L. Cain, Jay A. Frederick, Bob J. Oakleaf, and Shawn S. Sartorius. In Press.  Spatial Ecology of wolverines at the southern periphery of distribution.  Journal of Wildlife Management.

PrePrint available online at:  http://onlinelibrary.wiley.com/doi/10.1002/jwmg.289/abstract