bears and more • Klaus Pommerenke
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29. März 2015
Biologen und Wolfsspezialisten sprechen sich gegen das Wolfstötungsprogramm der Provinzregierung von BC aus
In einem Artikel in der Vancouver Sun vom 19. Februar 2015 (Opinion: Ecologists oppose B.C. wolf kill) sprechen sich John und Mary Theberge, beides Wolfsspezialisten mit langjähriger Forschungserfahrung, vehement gegen das Wolfstötungsprogramm der Provinzregierung von BC aus, durch welches die Überlebenschancen der durch Lebensraumverlust vom Aussterben bedrohten Bergkaribus erhöht werden sollen (vgl. Artikel vom 18.1., 26.1. und 17.2. auf dieser Website). Nachfolgend ist ihr in der Vancouver Sun erschienener Artikel wiedergegeben:
„By John and Mary Theberge, Special to the Vancouver Sun February 19, 2015 As two of Canada’s senior wolf biologists, we are disturbed the B.C. government is implementing massive wolf control plan with the low probability of recovering a few small, isolated, range-edge herds of mountain caribou.
As university-based biologists, we have run the longest, most intensive, telemetry-based wolf research program in Canada. We have published two books on our wolf research and many scientific papers including two on what constitutes valid biological evidence to assess the role of predators in limiting prey numbers.
Assessing the ecological consequences of a major intervention such as predator control is a complex task filled with uncertainty. The need for the government to explain itself is underlined by an amazing statement in its 2014 wolf management policy: ‘Attempts to control wolves to reduce predation risks on caribou has been a provincial priority since 2001. Wolf densities have been reduced; however, at this time, a correlation between reduced wolf densities and caribou recovery cannot be substantiated.’
Why has past wolf killing not worked? The government’s chosen reason seems to be wolf killing needs to be more intensive, and more long lasting; that choice is inferred in the wolf management policy. Another possibility is that no rise in caribou numbers is possible because of habitat destruction, regardless of the presence of wolves. Starvation, climate-caused winter kill, predation by bears and/or cougars, accidents such as avalanches and other unpredictable events are have taken a major toll.
We would place our bets, however, on a third reasons that wolf killing has not lead to caribou recovery. Over much of B.C., what is known as an ecological phase shift has happened. Ecologists know of such shifts: witness the fish and wildlife tragedy of the Bering Sea, and the non-recovered cod fishery of the Atlantic. Phase shifts are based on one-way environmental alterations in trophic and other complex ecosystem interrelationships. New species crowd out the potential for recovery of old ones. Recovery is generally beyond the scope of management intervention.
Across much of B.C., massive forest cutting has resulted in gross habitat alteration and fragmentation. The cost? A phase shift. Moose, benefiting from early successional forests after logging and other land uses have greatly extended their range in B.C. Numbers of elk and deer have adjusted, too. However, caribou, especially the southern mountain ecotype, have declined due to a loss of critical older-growth, lichen-clad forests. They have been victims, too, of habitat fragmentation preventing herd-to-herd ‘metapopulation’ flow that once reduced risks of local, herd extinctions.
Ecosystems are made up of interacting parts. Removing predators constitutes a major perturbation. It is a slippery slope, where, when you start, you are doomed to increasing intervention with unknown consequences. With fewer wolves, will moose and elk populations increase? Will their browsing inhibit forest regeneration? Should they be killed, too? (In B.C.’s 2010 plan for an aerial wolf kill, moose reduction was a management prescription, too) If caribou numbers were to increase, would grizzlies and black bears become more common predators on caribou? What then, kill them? (In the Revelstoke region, bears — grizzly and black — were the major predator on caribou from 1992-2006, according to an internal ministry report.)
How long do you keep on intervening in dubious and unpredictable ways? It takes 75, maybe 100 years to grow forest stands with the structure to maximize arboreal lichens that have long fed caribou. In the meantime, what does climate change deal out?
More ecological evidence argues against the government wolf kill. Every practicing wildlife biologist knows two landmark scientific publications show a straight line graph linking wolf population size to prey biomass (the live weight of prey in that region). It is simple. More prey, more wolves. Recover caribou to any reasonable population size and wolf populations will increase too, likely through increased production of young, reduced mortality, and ingress from surrounding areas. The government knows this too. Quoting from its 2014 wolf management policy, ‘When reduction ceases, wolf populations and predation rates quickly recover.’
What then? Just keep killing? The government could make a case for permanent drawdown or virtual elimination of wolves over the 10,000-15,000 square km involved, but if that is its unspoken objective, such a brutal form of wild-land management surely needs public discourse.
Realistically, caribou days in the southern part of their range are numbered. It is biologically futile to kill wolves to return to the former situation.
But much more than biology is involved. What about ethics and attitudes toward nature? We add our perspective as wolf biologists to the thousands who have registered similar concerns.
We thought we had crossed a divide over manipulating wilderness in such insensitive ways.
Ironically, at a global level, we have crossed such a divide. Recently the wolf was removed from the red species list of globally endangered species due to impressive recoveries in many European countries and in the lower 48 U.S. states. In the latter, wolf numbers have increased since 1973 but at a cost: Americans over the past decade have spent more than $6.2 million per year recovering the wolf.
We, in contrast, are about to spend about $2.5 million over five years to kill them but not without an encouraging amount of public protest, however. Across much of their global wolf range, wolves are far more accepted now, and people wear wolf T-shirts and buy wolf memorabilia. Could it be that just the government is out of step?
We find the killing of one of the world’s most highly developed social species for such arrogant reasons as manipulating wilderness to be reprehensible.
In our past research in Ontario’s Algonquin Park and elsewhere, and present research with recovering wolf populations in Yellowstone and Arizona, we have been privileged to learn to know wild wolves reasonably well and to study and feel first-hand their contribution to the iconic character of wild lands. When you come to appreciate individual wolves as personalities and as remarkable social animals, it becomes abhorrent to kill them for such dubious, pseudo-scientific reasons.
We are encouraged that so many others in B.C., across Canada and elsewhere have registered their concern. B.C. is out of step with current principles of wildlife ecology and environmental ethics.”
© John and Mary Theberge, The Vancouver Sun
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