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?