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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, August 23, 2014

A new friend of this blog, Biologist Shannon Barber-Meyer of the U.S. Geological Survey(USGS) forwarded to me the recent peer reviewed paper that biologists Ronald McRoberts and David Mech penned on the factors that limit Wolf populations............We also recently posted Dan MacNulty's(Biologist at Utah State) paper on related subject matter entitled: ("A Reappraisal of the Evidence for Regulation of Wolf Populations") which concluded that "wolf population regulation is goverened by density-dependence as much as limitation by prey availability"......... "The data suggested that wolf populations are self regulated rather than limited by prey biomass by at least a 3:1 margin"............ "In establishing goals for sustainable wolf population levels, managers of wolf re-introductions and species recovery efforts should account for the possibility that some regulatory mechanism plays an important role in wolf population dynamics"...........McRoberts and Mech enter into this discussion by postulating that "data do(es) not support the hypothesis that wolf densities are regulated by social factors"..........They go on to say that "social factors such as territoriality and intraspecific strife, age of first reproduction and dispersal do operate in wolf populations"......... "Ultimately, they might only fine tune basic wolf densities to biomass values at finer scales than have so far been measured"................."Our results also contradict the conclusion that an upper density bound of 69 wolves per 1000 square km2 exists in wolf populations"...........Instead, we found no evidence for a maximum wolf density except that dictated by biomass"............."Our analysis indicates that the question of whether wolf density is regulated by prey biomass or social factor as high prey densities should remain open"..............."The most important information that managers should consider is that regardless of what regulates wolf densities, such densities can fare exceed the 69/1000km2 proposed as an upper bound under the model of Cariappa et al.(2011; Table 2)"..............."Researchers however, should closely examine all possible regulating factors"......As Cubanynes et al.(2014) found, high wolf densities can increase intraspecific aggression"......"Although such aggression in itself may not regulate wolf populations because pup survival and dispersal are also critically important(Mech et al. 1998, Adams et al. 2008)......... "Aggression remains a factor to be considered and warrants further research on its role in wolf population regulation".........I truly enjoy the ongoing in-depth analysis of all things wolf and coyote in North America..............Always poignant "Point/Counter Point" theories put forward by so many qualified scientists------truly like a "battle of the titans" between Pro tennis standouts Rafael Nadal and Roger Federer-------120 mph "hard and true" serves back and forth,,,,,,,,,,,,back and forth...............David Mech stated in a recent INTERNATIONAL WOLF MAGAZINE article that the reason scientist disagree so much on these topics is that " that is the way science works".......Science is self-correcting".........One study concludes something; then the other scientists scrutinize the study and sometimes see problems with the first study's methods, analyses, results or interpretations"

Date: Fri, Aug 22, 2014 
To: Rick Meril
Fm: Shannon Barber-Meyer <>
Cc: "L. David Mech" <>

Hi Rick,
Have you seen the latest publication by McRoberts and Mech (2014) in The Journal of Wildlife Management that concludes that "data do not support the hypothesis that wolf densities are regulated by social factors"?

 Please post the abstract (below) to your blog for interested readers relative to your recent post on "Wolves will kill for more space" study in Yellowstone. I've also attached the entire manuscript.  Thank you!

Shannon Barber-Meyer, PhD
USGS, MN Wolf and Deer Project


 Wolf Population Regulation Revisited—Again

 U.S. Forest Service, Northern Research Station, 1992 Folwell Ave., St. Paul, MN 55108, USA 
U.S. Geological Survey, Northern Prairie Wildlife Research Center, 8711–37th St. SE, Jamestown, ND 58401, USA 

 The long-accepted conclusion that wolf density is regulated by nutrition was recently challenged, and the conclusion was reached that, at greater levels of prey biomass, social factors such as intraspecific strife and territoriality tend to regulate wolf density. We reanalyzed the data used in that study or 2 reasons: 1) we disputed the use of 2 data points, and 2) because of recognized heteroscedasticity, we used weighted-regression analysis instead of the unweighted regressions used in the original study. We concluded that the data do not support the hypothesis that wolf densities are regulated by social factors.

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