Monday, November 13, 2006

No scientific basis for current wolf control program

By Gordon Haber

Alaska’s aerial wolf-killing program now covers five areas equal to about two-thirds the size of Wyoming. Wolf control using snowmachines, other non-aerial methods, and even by allowing hunters to shoot adults while they are raising dependent pups at spring-summer dens and rendezvous sites is effectively under way over additional, much larger areas as well. Altogether, at least 1,500 wolves are killed annually in Alaska.

For most of this killing, state biologists and the Board of Game avoid the public process and written findings required for control programs by claiming they are merely providing wolf “harvesting” opportunities. However, they are unable to avoid these requirements for the five areas where airplanes are used. The details are revealing.

Foremost, the available information does not support the underlying claims about moose, caribou, and related hunting problems.

For example, state biologists continue to mislead Alaskans about the need for predator control in the McGrath area, where local hunters have enjoyed among the highest moose-hunting success rates in the state for at least 14 years. This is reminiscent of claims about the nearby Nowitna area in 1979, where state biologists insisted moose had declined from 2,000 to 1,000 and began an aerial wolf control program, only to determine a year later that there were actually 3,500-5,000 moose in the area. This past spring, state biologists convinced the board that it was necessary to triple the size of the Fortymile aerial wolf control area to boost caribou numbers — where caribou numbers have already doubled since 1997!

The only condition that might necessitate killing wolves to provide a sustainable ungulate harvest is the so-called predator pit, a low stable state that can occur at varying densities both naturally and via human causes. Because ungulate recruitment increases and decreases in counterintuitive ways across wide ranges of population densities, merely showing that there is low calf survival or that survival increases following a predator reduction does not suffice to identify a predator pit. Low calf survival and similar responses to predator reductions can also occur at high populations.

Recruitment information must be interpreted with good population estimates, and vice versa, in order to confirm a predator pit. But there are few if any reliable estimates of populations and their trends for the control areas, and the available information provides more reasons to question than accept the claims about current predator pits.

Game Management Unit 20A, south of Fairbanks, illustrates the importance of identifying this condition accurately and not otherwise jumping to conclusions about negative impacts on moose and moose-hunting even when wolves are at natural levels. Moose in 20A were overhunted into a likely predator pit in the early-mid 1970s, then rebounded during wolf control from 1976 to 1982. According to state reports, wolves recovered to natural or near-natural levels by mid 1983 and for the most part have remained there since. Yet during this period of relative wolf abundance — 1983-2006 — moose numbers increased another two-to-three-fold (within an upper “stable state”) and 20A has become the best moose-hunting area in Alaska.

In contrast to 20A wolves, 20A bears have remained at low levels, due to past heavy hunting and for other reasons. Thus the 1983-2006 observations also debunk the notion (e.g., at McGrath) that unchecked wolf predation during the winter will undo early calf-survival gains from reductions in bear predation.

Data from neighboring Denali National Park (in my doctoral dissertation), based on all the ungulates that two groups of wolves ate during 2,666 miles of their travels over a series of mild, severe, and average winters, help to explain why. The wolves scavenged rather than killed 60-77 percent of the moose they ate (47-48 percent of the moose, sheep, and caribou they ate combined) and killed only 2.0-8.9 percent of the moose they encountered. The state’s findings for the control areas are full of speculation about predation impacts but mention nothing about this Denali research, the most detailed and extensive body of wolf foraging information ever published.

I invite readers to consider the details of these and related arguments. They appear in a 67-page scientific review — with citations to 81 other reports — that I submitted to the Board of Game at the March-May 2006 meetings (as RC-35 and RC-201). The board neither considered nor even mentioned this and other scientific opposition during its subsequent deliberations.

Once again, agency biologists and the board have been able to avoid meaningful review and sell their gratuitous control programs to Alaskans under the guise of “science.”

Gordon Haber, Ph.D., has studied wolves and wolf-ungulate systems in Alaska since 1966.

  • Fairbanks Daily News-Miner