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Wolf Control in McGrath: Where are the Doctor's orders?

Vic Van Ballenberghe / November 1, 2004

Suppose you were feeling ill and went to a medical doctor for treatment. The doctor listens to your symptoms, then orders some diagnostic tests to identify the cause of the problem. Once the cause is evident, treatment is prescribed after the risks and benefits are explained. You may get a second opinion as doctors are human and may commit errors or may disagree on the best treatment strategy. During all of this you expect that the medical advice you get is science-based, i.e., the result of properly done experiments coupled with experience treating other patients with similar problems.

You may then go home and decide your course of action. Perhaps you have no insurance and can't afford treatment. Perhaps the risk of treatment is too high and you choose not to proceed. Perhaps your relatives and friends influence your decision. These non-science issues may outweigh the medical advice, but you must still be confident that the doctor's advice is sound. It forms the foundation to proceed if you choose to do so.

Wildlife management is not much different-it is a mix of science and non-science issues. Management actions must first have a sound scientific base. Public policy decisions by the Board of Game and the Governor may then include other considerations, but the science base cannot be ignored without risking failure. Over the past twenty-five years science has expanded greatly in the wildlife field and we now understand much about the relationships between wildlife populations and their environment. This is especially true for predation on large mammals like moose and caribou. Numerous studies across North America have revealed many aspects of predation by wolves and bears and allowed managers to predict the outcome of management actions like predator reduction. Unfortunately, management is often driven by politics and science takes a back seat.

About six years ago local people at McGrath noticed that the moose population in that area was declining. Wolves were thought to be abundant and wolf control was proposed to rebuild the moose population. Very little biological information was available on the number of moose or wolves, moose calf mortality, habitat conditions, bear predation, the effects of severe winters on moose, or any of the other factors that might be responsible for a declining moose herd.

Over the ensuing years, three moose censuses and two wolf surveys have indicated declining moose and wolf populations. Although black bears are abundant, little is known about their predation on moose calves. Studies in other areas suggest that up to half the annual calf crop may be lost to bears. Similarly, moose habitat in much of the area is thought to be poor, but no estimates of carrying capacity are available. Clearly, extensive tracts of mature spruce-aspen forest cannot support many moose until fires create better forage for moose. Even the hunting take and its impact on moose are in doubt as harvest estimates are clouded by under-reporting,

Despite this lack of information, the Board of Game approved a wolf control plan for the McGrath area. This is analogous to a medical doctor prescribing treatment before doing the necessary diagnostic tests. The Commissioner of Fish and Game decided not to implement the plan whereupon local residents appealed to the media and the legislature for relief. The Governor then appointed an advisory group to examine the issues and provide recommendations to the Commissioner. This group is now poised to recommend both wolf and black bear control programs.

Last September the advisory group invited two biologists outside the Department of Fish and Game to discuss the science of predator control at McGrath. As a biologist with experience studying predation my main concern was whether or not the proposed wolf control plan passed by the Board of Game met the Governor's test that it must be based on sound science. I reviewed the available data and concluded that the information base was weak. I indicated that I felt that this was not a close call, that qualified, experienced ecologists would agree that several important pieces of the puzzle were missing. I think the National Academy of Sciences panel that reviewed Alaska's past predator control programs would agree that more information is required before launching a control program.

What information gaps exist? At this point, no one can say for certain that predation by bears and wolves is limiting moose population growth. Indeed, statistics from the moose population suggest that predation is not severe. The percentage of calves in the late winter population was 22% in 1999. This is not indicative of heavy predation and much reduced calf survival. The best way to determine calf mortality rates and identify the role of predation affecting calf survival is to radio collar newborn calves and locate them daily during the first two months of life. Three years of such studies with about 50 calves collared each year would reveal a lot about the importance of predation in limiting moose numbers. If the same patterns of predation prevail at McGrath as elsewhere, and if predation is significant there, it is likely that mortality studies would suggest that bear reduction would result in far more moose than would wolf reduction. Similarly, no one can say for certain that the available moose habitat could support two or three times the current moose population, even if predators are totally eliminated. The science behind determining carrying capacity is far more difficult and expensive than calf mortality studies and may not be necessary over the entire area. But some data are needed to ensure that there is enough forage to support additional moose, at least in the river corridors where about 50% of the current moose are located in autumn.

In the medical field, weak science leads to uncertain diagnoses, unclear treatments, and unmeasured risks. Similarly, wildlife science may be weak, or we may fail to apply it properly, or ignore the science altogether as politics drive decision making. At a minimum, the risk of having weak information is that money and effort will be wasted and management actions will fail to increase moose. This issue is too important to leave science questions unanswered. The Board of Game should not be in the position of the doctor telling the patient's family that he died because science-based treatments were not applied.

Vic Van Ballenberghe is a wildlife biologist who has studied moose and predation in several areas of Alaska since 1974.

 
 
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