With the arrival of the first wolf in California since the
1920s, no doubt the California Department of Game and Fish is receiving
many comments from the public. The quality of this support, opposition
and advice probably varies all over the map (the maps in our heads).
Norman Bishop, who played a key role as a Yellowstone Park naturalist
educating the public about the wolves that were coming to Yellowstone
and then after their arrival until 1997, has compiled a fact-filled
piece “What Good are Wolves.” This morning he announced he had sent it
to the Director of the California Department of Fish and Game.
In the current politically charged and cognitively challenged
atmosphere of wolf mythology, the contents of this letter should be
shared with the public because summarizes what had been learned in
recent years so compactly and lucidly.
What good are wolves? Compiled by Norman A. Bishop
In 1869, General Phil Sheridan said, “The only good Indians I ever
saw were dead.” Others said, “The only good wolf is a dead wolf.”
Barry Lopez wrote of an American Pogrom, not only of Native Americans
and wolves, but of the bison on which both depended. Between 1850 and
1890, 75 million bison were killed, mostly for their hides; perhaps one
or two million wolves.
“Before about 1878, cattlemen were more worried about Indians killing
their cattle than they were about wolves. As the land filled up with
other ranchers, as water rights became an issue, and as the Indians were
removed to reservations, however, the wolf became, as related in Barry
Lopez’s book, Of Wolves and Men, ‘an object of pathological
hatred.’” Lopez continues: “(T)he motive for wiping out wolves (as
opposed to controlling them) proceeded from misunderstanding, from
illusions of what constituted sport, from strident attachment to private
property, from ignorance and irrational hatred.”
In 1884, Montana set a bounty on wolves; in the next three years,
10,261 wolves were bountied. “In 1887, the bounty was repealed by a
legislature dominated by mining interests.” *** “By 1893,… desperate
stockmen were reporting losses that were mathematical impossibilities.
The effect of this exaggeration was contagious. The Montana sheep
industry, which up to this time had lost more animals to bears and
mountain lions than to wolves, began to blame its every downward
economic trend on the wolf. *** Men in a speculative business like
cattle ranching singled out one scapegoat for their financial losses.”
Not until wolves were functionally extinct from much of the West did
anyone begin to ask, “What good are wolves?” to study wolves, and to
report their beneficial effects on their prey species and on the
ecosystems where they lived.
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.
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. It has also reminded us that
predation is one of the dominant forces in all of nature, present in
ecosystems worldwide over millions of years.
Bob Crabtree and Jennifer Sheldon note that predation by wolves is
important to the integrity of the Yellowstone ecosystem, but we should
realize that, before their return to Yellowstone’s northern range, 17
mountain lions there killed 611 elk per year, 60 grizzly bears killed
750 elk calves annually, and 400 coyotes killed between 1100 and 1400
elk per year.
P.J. White et al wrote that climate and human harvest account for
most of the recent decline of the northern Yellowstone elk herd, coupled
with the effects of five predators: wolves, grizzly bears, black bears,
cougars, and coyotes. These are parts of a system unique in North
America by its completeness.
Joel Berger et al demonstrated “a cascade of ecological events that
were triggered by the local extinction of grizzly bears…and wolves from
the southern greater Yellowstone ecosystem.” 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.
Dan Tyers informs us that wolves haven’t eliminated moose from
Yellowstone. Instead, burning of tens of thousands of acres of moose
habitat in 1988 (mature forests with their subalpine fir) hit the moose
population hard, and it won’t recover until the forests mature again.
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.
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. 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). In Yellowstone, grizzly bears
prevailed at 85% of encounters over carcasses, and they usurp nearly
every kill made by wolves in Pelican Valley from March to October. Some
445 species of beetle scavengers benefit from the largess of
wolf-killed prey. In Banff and Yellowstone, no other predator feeds as
many other species as do wolves. Wolf-killed elk carcasses enhance
local levels of soil nutrients; 20-500% greater nitrogen, phosphorous
and potassium.
Dan Stahler and his colleagues saw an average of four ravens on
carcasses in Lamar Valley pre-wolf. Post-wolf, that increased to 28
average, with as many as 135 seen on one carcass. Eagles seen on
carcasses increased from an average of one per four carcasses to four
per carcass.
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.
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.
Chris Wilmers and Wayne Getz write that wolves buffer the effects of
climate change. In mild winters, fewer ungulates die of winterkill,
causing loss of carrion for scavengers. Wolves mitigate late-winter
reduction in carrion by killing ungulates all year.
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.
Mark Hebblewhite reviewed the effects of wolves on population
dynamics of large-ungulate prey, other effects on mountain ecosystems,
sensitivity of wolf-prey systems to top-down and bottom-up management,
and how this may be constrained in national park settings. Then he
discussed the implications of his research on ecosystem management and
long term ranges of variation in ungulate abundance. He cites
literature that suggests that the long-term stable state under wolf
recovery will be low migrant elk density in western montane ecosystems.
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.
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.
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.
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.”
What good are wolves? References cited
Berger, Joel , Peter B. Stacey, Lori Bellis, and Matthew P. Johnson.
2001. A mammalian predator-prey imbalance: grizzly bear and wolf
extinction affect avian neotropical migrants. Ecol. Applications
11(4):947-960.
Crabtree, Robert L., and Jennifer W. Sheldon. Coyotes and Canid Coexistence in Yellowstone. Pages 127-163 in
Clark, Tim W., A. Payton Curlee, Steven C. Minta, and Peter M.
Kareiva. 1999.
Carnivores in Ecosystems: The Yellowstone Experience.
Yale U. Press. 429 pp.
Creel, Scott, and J.A. Winnie, Jr. 2005. Responses of elk herd size
to fine-scale spatial and temporal variation in the risk of predation
by wolves. Animal Behaviour 69:1181-1189.
Duffield, J., C. Neher, and D. Patterson. 2006. Wolves and People
in Yellowstone: Impacts on the Regional Economy. Department of
Mathematical Sciences, The University of Montana.
Errington, Paul L. 1967. Of Predation and Life. Iowa State Univ. Press, Ames. 277 p.
Fortin, D., H. Beyer, M.S. Boyce, D.W. Smith, T. Duchesne, and J.S.
Mao. Wolves influence elk movements: behavior shapes a trophic cascade
in Yellowstone National Park. Ecology 86(5):1320-30.
Hebblewhite, Mark. 2010. Predator-Prey Management in the National Park
Context: Lessons from a Transboundary Wolf, Elk, Moose and Caribou
System (Pp. 348-365 in Transactions of the 72nd North American Wildlife
and Natural Resources conference.
Hebblewhite, Mark, and Douglas W. Smith. 2007. Wolf Community Ecology: Ecosystem Effects of Recovering Wolves in Banff and Yellowstone National Parks in Musiani, M., and P.C. Paquet. The World of Wolves: new perspectives on ecology, behaviour, and policy. U. of Calgary Press.
Hobbs, N. Thompson. 2006. A Model Analysis of Effects of Wolf
Predation on Prevalence of Chronic Wasting Disease in Elk Populations of
Rocky Mountain National Park.
Johnson, Mark R. 1992. The Disease Ecology of Brucellosis and
Tuberculosis in Potential Relationship to Yellowstone Wolf Populations.
Pp. 5-69 to 5-92 in Varley, J.D., and W.G. Brewster, Ed’s. Wolves for Yellowstone? A report to the United States Congress. Volume IV, Research and Analysis.
Leopold, Aldo. 1938. Unpublished essay, “Conservation,” on Pp. 145-6 of Round River, 1953.)
Leopold, Aldo. 1949. A Sand County Almanac. Oxford University Press. P. 204 and Pp. 224-225.
Lopez, Barry H. 1978. Of Wolves and Men. Charles Scribner’s Sons. New York. 308 p.
Murie, Adolph. 1944. The Wolves of Mount McKinley. Fauna of the
National Parks of the United States. Fauna Series No. 5. USGPO,
Washington, D.C.
Murie, Olaus J. The Elk of North America. 1951. Stackpole Co., Harrisburg, Pa., and Wildl. Mgmt. Inst., Wash., D.C. 376 pp.
Pimlott, Douglas H. 1967. Wolf Predation and Ungulate Populations. Amer. Zool. 7: 267-78.
Smith, Douglas W. Personal communication.
Stahler, Daniel, Bernd Heinrich, and Douglas Smith. 2002. Common ravens, Corvus corax, preferentially associate with grey wolves, Canis lupus, as a foraging strategy in winter. Animal Behaviour 64:283-290. El Sevier.
Tyers, Daniel B. 2003. Winter Ecology of Moose on the Northern Yellowstone Winter Range. Ph.D. Dissertation, MSU, Bozeman.
White, P.J., and R.A. Garrott. 2005. Yellowstone’s ungulates after
wolves – expectations, realizations, and predictions. Biological
Conservation 125:141-52.
White, P.J., Robert Garrott, and Lee Eberhardt. 2003. Evaluating
the consequences of wolf recovery on northern Yellowstone elk.
YCR-NR-2004-02.
Wilmers, C.C., and W.M. Getz. 2005. Gray wolves as climate change buffers. PLoS Biology 3 (4):e92.
Wilmers, C.C., R.L. Crabtree, D.W. Smith, K.M Murphy, W.M. Getz.
2003. Trophic facilitation by introduced top predators: grey wolf
subsidies to scavengers in Yellowstone National Park. Journal of Animal
Ecology 72(6):909-16.
About the compiler
After university work in Botany, Zoology, Forest Recreation, and
Wildlife Management, and 4 years as a naval aviator, Norman A. Bishop
was a national park ranger for 36 years. He was the principal
interpreter of wolves and their restoration at Yellowstone National Park
from 1985 to 1997, when he retired to Bozeman.
For his educational work on wolves, he received a USDI citation for
meritorious service. He also received the National Parks and
Conservation Association’s 1988 Stephen T. Mather Award, the Greater
Yellowstone Coalition’s 1991 Stewardship Award, and the Wolf Education
and Research Center’s 1997 Alpha Award.
He led many field courses on wolves for the Yellowstone Association
Institute until 2005. He is the greater Yellowstone region field
representative for the International Wolf Center. He serves on the
boards of the Wolf Recovery Foundation, and Wild Things Unlimited. He
is also on the advisory board of Living with Wolves.
Norman A. Bishop
Bozeman, MT 59715
source
No comments:
Post a Comment