Posted by: WCFN | November 12, 2012

Wolves help biodiversity


Wolves, like other top predators, actually help biodiversity





The following is a short version, selected by WCFN from:


What good are wolves?
Compiled by Norman A. Bishop

Predation is one of the dominant forces in all of nature.


“Adolph Murie realized that wolves selected weaker Dall sheep, “which may be of great importance to the sheep as a species.”

His brother, Olaus J.Murie, thought predators may have an important influence during severe winters in reducing elk herds too large for their winter range.

Douglas H. Pimlott pointed out that wolves control their own densities.”

THE IMPORTANCE OF APEX PREDATORS

The wolf has been reintroduced in the Yellowstone National Park and has been spreading in adjacent areas.

Yellowstone National Park wolf project leader Douglas W. Smith says that restoration of wolves there has added exponentially to our knowledge of how natural ecosystems work.

Mark Hebblewhite and Doug Smith documented that wolves change species abundance, community composition, and physical structure of the vegetation, preventing overuse of woody plants like willow, reducing severity of browsing on willows that provide nesting for songbirds.

In Banff, songbird diversity and abundance were double in areas of high wolf densities, compared to that of areas with fewer wolves . Fewer browsers lead to more willows, providing habitat for beaver, a keystone species, which in turn create aquatic habitat for other plants and animals.

The reintroduction of wolves has diminished coyote population and predation, actually helping the pronghorn.

By reducing coyotes, which were consuming 85% of the production of mice in Lamar Valley, restored wolves divert more food to raptors, foxes, and weasels.

By concentrating on killing vulnerable calf elk and very old female elk, wolves reduce competition for forage by post-breeding females, and enhance the nutrition of breeding-age females.

In about 75 years, moose in Grand Teton National Park erupted to five times the population outside, changed willow structure and density, and eliminated neotropical birds; Gray Catbirds and MacGillivray’s Warblers.

Wolves promote biological diversity, affecting 20 vertebrate species, and feeding many scavengers (ravens, magpies, pine martens, wolverines, bald eagles, gray jays, golden eagles, three weasel species, mink, lynx, cougar, grizzly bear, chickadees, Clark’s nutcracker, masked shrew and great grey owl).

P.J. White and Bob Garrott observed that, by lowering elk numbers, wolves may contribute to higher bison numbers; by decreasing coyote populations, result in higher pronghorn numbers. They also said wolves may ameliorate ungulate-caused landscape simplification.

Mid-sized predators can be destructive in the absence of large keystone predators. In the absence of wolves, pronghorn have been threatened with elimination by coyotes. Wolves have reduced coyotes, and promoted survival of pronghorn fawns. Pronghorn does actually choose the vicinity of wolf dens to give birth, because coyotes avoid those areas, according to Douglas W. Smith.

Daniel Fortin and others saw that wolves may cause elk to shift habitat, using less aspen, and favoring songbirds that nest in the aspen.

Christopher Wilmers and all tell us that hunting by humans does not benefit scavengers the way wolf kills do. Carrion from wolf kills is more dispersed spatially and temporally than that from hunter kills, resulting in three times the species diversity on wolf kills versus hunter kills.

Wolves subsidize many scavengers by only partly consuming their prey; they increase the time over which carrion is available, and change the variability in scavenge from a late winter pulse (winterkill) to all winter. They decrease the variability in year-to-year and month to-month carrion availability.

Noting that wolves may be a keystone species, without which ungulate densities increase, vegetation communities become overbrowsed, moose and beaver decline, and biodiversity is reduced. But as elk decline, aspen and willow regeneration are enhanced. In this context, wolf predation should be viewed as a critical component of an ecosystem management approach across jurisdictions.

wolf howling

WOLF PREDATION MAY SLOW DISEASE SPREAD


Chronic wasting disease could wipe out our elk and deer. Tom Hobbs writes that increasing mortality rates in diseased populations can retard disease transmission and reduce disease prevalence. Reduced lifespan, in turn, can compress the time interval when animals are infectious, thereby reducing the number of infections produced per infected individual.

Results from simulations suggest that predation by wolves has the potential to eliminate CWD from an infected elk population.

Wildlife veterinarian Mark R. Johnson writes that wolves scavenge carrion, such as aborted bison or elk calves. By eating them, they may reduce the spread of Brucellosis to other bison or elk.

Scott Creel and John Winnie, Jr. report that wolves also cause elk to congregate in smaller groups, potentially slowing the spread of diseases that thrive among dense populations of ungulates.


ECONOMIC VALUE


John Duffield and others report that restoration of wolves has cost about $30 million, but has produced a $35.5 million annual net benefit to greater Yellowstone area counties, based on increased visitation by wolf watchers. Some 325,000 park visitors saw wolves in 2005.

In Lamar Valley alone, 174,252 visitors observed wolves from 2000 to 2009; wolves were seen daily in summers for nine of those ten years.


HUMAN VALUES & ETHICS


Wolves cause us to examine our values and attitudes. Paul Errington wrote, “Of all the native biological constituents of a northern wilderness scene, I should say that the wolves present the greatest test of human wisdom and good intentions.”


Aldo Leopold, father of game management in America, said, “Harmony with land is like harmony with a friend; you cannot cherish his right hand and chop off his left. That is to say, you cannot love game and hate predators; … The land is one organism.”


Leopold also pointed out that the first rule of intelligent tinkering with natural ecosystems was to keep all the pieces. Eliminating predators is counter to that advice.


Wolves remind us to consider what is ethically and esthetically right in dealing with natural systems. As Leopold wrote in his essay “The Land Ethic,” “A land ethic …does affirm (animals’) right to continued existence…in a natural state.” He concluded, “A thing is right when it tends to preserve the integrity, stability, and beauty of the biotic community. It is wrong when it tends otherwise.”



Read the whole article as quoted by Cathy Taibbi, here:    The Examiner


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WOLVES ARE BEING HUNTED AND TRAPPED AGAIN 


After the Great Lakes wolves, Minnesota’s wolves lost federal protection under the Endangered Species Act earlier this year (2012). State managers rushed to authorize wolf hunting and trapping. Hunters shot and needlessly killed more than 120 of Minnesota’s wolves in the first 12 days of the hunt. The state’s goal is to kill 400 by the end of the season.


Wolf trapping season begins Nov. 24, and hundreds more of these beautiful and intelligent animals will suffer and die in gruesome leghold traps and snares.


Wolves are an essential part of the American wildscape. They regulate prey populations and help maintain biodiversity. Sport hunting and trapping may actually exacerbate problems between domestic animals and wolves. Sport killings disrupt pack dynamics and create lone wolves that are more apt to target livestock or pets out of desperation.


Source: The Center for Biological Diversity


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