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Grizzly bears, black bears, wolves, coyotes, cougars/ mountain lions,bobcats, wolverines, lynx, foxes, fishers and martens are the suite of carnivores that originally inhabited North America after the Pleistocene extinctions. This site invites research, commentary, point/counterpoint on that suite of native animals (predator and prey) that inhabited The Americas circa 1500-at the initial point of European exploration and subsequent colonization. Landscape ecology, journal accounts of explorers and frontiersmen, genetic evaluations of museum animals, peer reviewed 20th and 21st century research on various aspects of our "Wild America" as well as subjective commentary from expert and layman alike. All of the above being revealed and discussed with the underlying goal of one day seeing our Continent rewilded.....Where big enough swaths of open space exist with connective corridors to other large forest, meadow, mountain, valley, prairie, desert and chaparral wildlands.....Thereby enabling all of our historic fauna, including man, to live in a sustainable and healthy environment. - Blogger Rick

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Saturday, February 10, 2018

The first ever direct estimate of wolf kill rates and predation rates of beavers was researched during 2015 in Minnesota's Voyageurs National Park............Two previous studies had relied on scat analysis, an imperfect measure of what an animal consumes because it does not determine direct kills versu scavenging.........U. of Minnesota biologist Thomas Gable and National Park Service biologist Steve Windels monitored one specific Wolf from April 1-November 5, 2015 and determined that it killed 22 Beaver.............Using this statistic, their extrapolated projection determined that Great Lake Wolf packs kill roughly 40% of the Beaver in their territory, a % that would seem to suggest that Wolves drastically dampen Beaver populations annually........"Note that stable or growing beaver populations typically decrease when total annual mortality rates exceed 25–33% (Henry and Bookhout 1969; Payne 1984, 1989; Novak 1987; Potvin et al. 1992)"................."However, further investigation by Gable and Windels showed that beavers from adjacent territories so replaced the Beaver taken by the Wolves, that the Beaver population actually increased by 43% the following year of 2016"............"These results suggest that wolf predation on dense beaver populations has minimal impact".............. "For example, the 43% increase in beaver density in the study region from 2015 to 2016 was consistent with the 27% increase in beaver lodge density in Voyageurs Park as a whole during the same period (S. K. Windels, unpublished data)"


Kill Rates and Predation Rates of Wolves on Beavers 

THOMAS D. GABLE , 1 Voyageurs National Park, 360 Highway 11 E, International Falls, MN 56649, USA STEVE K. WINDELS, Voyageurs National Park, 360 Highway 11 E, International Falls, MN 56649, USA 

ABSTRACT Wolves (Canis lupus) can be primary predators of beavers (Castor canadensis), but little is known about wolf-beaver dynamics. We identified kills from 1 wolf (V009) of the Ash River Pack in Voyageurs National Park from 1 April to 5 November 2015 to provide direct estimates of wolf pack kill and predation rates of beavers. 

 We documented 12 beaver kills by V009 during the 2015 ice-free season and estimated V009 killed 22 beavers during this period. Based on the number of beavers killed by V009, we estimated the Ash River Pack removed 80–88 beavers (kill rate of 0.085–0.095 beavers/wolf/day), which was 38–42% of the beaver population in their home range during the ice-free season. 

Even with this substantial level of predation in 2015, the beaver population in the Ash River Pack home range increased by an estimated 43% in 2016, which suggested dispersal from more densely populated adjacent areas likely compensated for the effects of wolf predation. 

We have presented the first direct estimate of wolf kill and predation rates on beavers, but more research is necessary to understand how wolf predation affects beaver populations under a variety of conditions

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