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Coyotes-Wolves-Cougars.blogspot.com

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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Thursday, June 19, 2014

We hear again from Trophic Carnivore scientist Bill Ripple and T.M. Newsome reinforcing the Leopoldian ethos that it is so critical to keep "all the cogs and wheels" for a given natural system to operate at peak form---AND THAT THE SIZE OF THE LAND AREA WHERE THE APEX CARNIVORES ARE PATROLING MUST BE OF A LANDSCAPE SCALE,,,NOT JUST A SUBJECTIVE SWATH OF LAND DESIGNATED BY POLITICAL OFFICIALS............" That apex predators are critical to maintain a healthy ecosystem isn’t all that surprising"..... "At least not anymore"............ "When wolves were exterminated from most of the lower United States, a set of perhaps unexpected consequences followed: deer numbers increased, which meant that plant populations declined"............. "Bears, who eat many of the same plants that deer eat, suffered from having to share their food"............. "When wolves were reintroduced to Yellowstone, the entire community shifted back into relative balance"..................."Large carnivores like wolves may need large, continuous territories in order to effectively control the balance of their ecosystems".............. "What does that mean for efforts to reintroduce wolves to bits of protected land in North American, increasingly surrounded by coyote-friendly agricultural fields?" ................"It might mean that wolves would be unable to control the coyote populations at all!".

http://conservationmagazine.org/2014/06/reintroducing-wolves-is-only-effective-at-large-scales/

REINTRODUCING WOLVES IS ONLY EFFECTIVE AT LARGE SCALES

It is a rule in ecology that big animals outcompete little animals. Sometimes the big animals kill the little animals, sometimes the big animals eat the little animals, and sometimes the big animals drive the little animals out of one territory and into another, safer one. That basic pattern – “interspecific competitive killing” – has pushed scientists to try to understand how large carnivores shape entire ecosystems.
That apex predators are critical to maintain a healthy ecosystem isn’t all that surprising. At least not anymore. When wolves were exterminated from most of the lower United States, a set of perhaps unexpected consequences followed: deer numbers increased, which meant that plant populations declined. Bears, who eat many of the same plants that deer eat, suffered from having to share their food. When wolves were reintroduced to Yellowstone, the entire community shifted back into relative balance.


But studies of wolves’ impact on ecosystems like Yellowstone National Park don’t typically cover all that much land, relatively speaking. Yellowstone Park incorporates some 8900 square kilometers, while the “Greater Yellowstone Ecosystem” covers an expanse more than eight times larger. Findings from within the park may not apply more broadly, simply because ecosystems aren’t limited to the artificial boundaries we impose.
Researchers Thomas M. Newsome and William J. Ripple, from Oregon State University, argue that they’ve achieved a better understanding of wolves’ roles in North American ecosystems because they’ve looked at data from an area covering nearly 1.3 million square kilometers of wilderness: the two large Canadian provinces of Saskatchewan and Manitoba. To assess the abundance of three carnivorous canids – wolves, coyotes, and foxes – they relied mainly on fur trap data.
In North America, wolves are known to kill coyotes, and coyotes are known to kill red foxes. Wolves are the apex predators, and coyotes and foxes are called mesopredators (since they are both predator and prey). As humans killed off the wolves, coyotes began to take over the continent, since their main competitor was suddently missing. Then, we began to re-introduce wolves to parts of their historical range. That gave Newsome and Ripple a sort of “natural experiment” – how do coyotes and foxes cope with the presence or absence of wolves?
Theoretically, the absence of wolves would lead to an increase in coyotes. And that, in turn, would be bad news not just for foxes, but also for the variety of smaller animals that coyotes eat: jackrabbits, cottontail rabbits, and pygmy rabbits, among others. Indeed, that’s what Newsome and Ripple predicted: “that in the presence of wolves there will be relatively more fur returns for red foxes than coyotes. In the absence of wolves we predict there will be relatively more fur returns for coyotes than red foxes.” That’s because wolves exert control over coyote populations. Where they’re present, the pressure on coyotes allows foxes to flourish; where they’re absent, coyotes proliferate, and foxes suffer.
On taking a first pass through the data, their initial hypotheses were confirmed. “Across multiple jurisdictions and spatial scales, we show in areas where wolves are present that red fox fur returns outnumber coyote fur returns,” they write. And “in the absence of wolves we show that coyote fur returns outnumber red fox fur returns.”
wolf map Reintroducing wolves is only effective at large scales
The darker the plot, the more coyotes relative to foxes. Even within wolf territory, coyotes dominate for up to 200 kilometers. Compare the study area with the relative sizes of the National Parks, on the right.
But it turns out that the inter-carnivore dynamics among wolves, coyotes, and foxes aren’t quite that simple. Because the area of land they investigated was so large, Newsome and Ripple discovered a large-scale “transition zone” at the edge of wolf territory, in which the ratio between foxes and coyotes shifts according to how far a population is from the center of wolf territory. That’s because wolves become more rare closer to the edge of their territory than in the center. That transition zone stretches for an impressive 200 kilometers. In other words, it is only 200 kilometers away from the edge of wolf territory that foxes begin to outnumber coyotes.
That means that the wolf-coyote-fox relationship is not linear. It suggests that wolves exert greater control over coyotes in some areas, but less control in others. The pattern that results is a sort of “ramp,” where coyotes dominate foxes farther away from wolf territory, but are increasingly subject to the wolf effects closer in. The “ramp” pattern also underscores coyotes’ remarkable ability to disperse. It explains why the reintroduction of wolves within Yellowstone National Park had the expected result of reducing coyote numbers, but also why the overall coyote populations within the Greater Yellowstone Ecosystem did not change. If wolves move into the neighborhood, coyotes simply pack up and move next door.
From a conservation perspective, this study highlights the wolves’ need to occupy large areas to carry out their “ecosystem services” of controlling mesopredators and maintaining healthy wildlife communities. “No study,” write Newsome and Ripple, “has previously quantified the size of the ‘border region’ or ‘transition zone’ that influences the effectiveness of top-down mesopredator control. Nor has it previously been appreciated that the border region may be of this magnitude.” Large carnivores like wolves may need large, continuous territories in order to effectively control the balance of their ecosystems. What does that mean for efforts to reintroduce wolves to bits of protected land in North American, increasingly surrounded by coyote-friendly agricultural fields? It might mean that wolves would be unable to control the coyote populations at all!
Taken together, Newsome and Ripple demonstrate that fully understanding ecosystem dynamics requires surveying much larger swaths of land than what’s contained within (relatively) tiny national parks. By focusing on smaller bits of land, researchers may be missing the proverbial forest for the trees. – Jason G. Goldman | 18 June 2014
Source: Newsome T.M. & Ripple W.J. (2014). A continental scale trophic cascade from wolves through coyotes to foxes., The Journal of animal ecology, PMID: 

5 comments:

Anonymous said...

Of course, this subject(wolves/coyotes/red foxes and their effects on each others' numbers) makes me wonder how the original populations of Red Wolves played into all this. Did they have a controlling effect on red foxes, like coyotes do, so that is why red foxes were not as numerous(even absent in some areas despite such areas being excellent fox habitat) in the Eastern U. S. when the Europeans first invaded? I wonder if anything has been done studying this subject specifically where the current "old bloodlines" descendants of red wolves are now in eastern N. C., or with the "new bloodlines" of red wolves(just my opinion on that....)--the "coywolves" in the northeastern U. S. and elsewhere are repopulating--I do know red foxes certainly survive in areas with red wolves/coywolves, but maybe not as numerous in coyoteless areas(if there ARE any coyoteless areas anymore!!!).....L.B.

Rick Meril said...

fair question LB............guessing that red wolves probably did keep foxes at peripheries of their territories as they were next down in the canid pecking order...........with gray wolves more numerous as per their ability to climb trees when threatened

Anonymous said...

Ha! Okay, Rick, I know that gray WOLVES climbing trees was a typo, but I wouldn't be surprised if other readers didn't realize you meant gray FOXES! However, typos are often inadvertently fun, and the image of gray wolves high-tailing it up trees to get away from red wolves is just too funny to not poke fun at! That WOULD be a good argument(ahem!) in regards to red wolves NOT being a naturally occurring hybrid between coyotes and gray wolves, because, well, it's very difficult to mate with a gray wolf up in a tree! Ha!....L.B.

Rick Meril said...

you got me LB...........long day and the mind wanders :)

Rick Meril said...

you got me LB...........long day and the mind wanders :)