Whither the Wolverine?
Due to petitions of a number of environmental groups, the US Fish and Wildlife Service (USFWS) appears likely to list the wolverine under the Endangered Species Act (ESA). Once found across much of the West and northern-tier states from Minnesota to Maine, wolverines are now limited to a few isolated populations in the western United States. Wolverines are a wide ranging predator that are adapted to survival in cold snowy climates.
Trapping, combined with poisoning programs aim at other predators like wolves, originally contributed to the wolverines demise across much of its former territory. However, global warming is the latest threat to its survival in the lower 48 states. Though population estimates vary, the best available “guesses” (and I say guess because no region- wide efforts to document population numbers has been completed) are that there are no more than 250-300 wolverine in the lower 48 states, with the majority of them residing in Montana.
Because of these precariously low numbers, trapping of wolverine has been banned in all states where they are found, except Montana. The Montana Dept. of Fish, Wildlife and Parks (MDFWP) argue that trapping is not a major source of mortality or a threat to the species.
Furthermore, they restrict the number of wolverine that can be trapped in any one part of the state which they claim ensures that trapping will not harm the species.
In response to the USFWS determination that wolverine warrant protection under the ESA, MDFWP has announced that it will seek an exemption to trapping of wolverine in Montana once the species is listed under the ESA.
We all know that climate change is one of the factors that threaten the long-term survival of wolverine in the lower 48 states. But doing anything about climate change in the near future is not likely to change this scenario, and all models suggest wolverine habitat is shrinking, thus fewer wolverine in a population, that is already precariously low, for long-term survival.
The one thing we have immediate control over is optional forms of human caused mortality such as trapping. While the number of animals lost to trapping may seem small (5 a year), there are biological reasons why trapping may contribute to greater losses than that number suggests. Due to the social behavior ecology of wolverine, the trapping of one individual can lead to the death of several to many more wolverine.
Furthermore, even the additional loss of one or two animals from a single mountain range may be sufficient to push that island population to extinction. As the wolverine in mountain range after mountain range wink out, the species is pushed ever closer to extinction.
Finally, the elephant in the room that MDFWP totally ignores is the ethics of trapping in a modern age. Is it really ethical to inflict avoidable pain upon other animals? Trapping amounts to torture. Most of us would be outraged if a dog owner put their pet in a trap and left it for hours or days to suffer. Hunters are admonished to make a “clean kill” so that animals they shoot do not suffer. Why do we allow trappers to inflict pain and suffering on wolverine, wolves or other animals? For what reason, do these few trappers need to trap wolverine? To eat? To sell a couple of pelts for income? Are these elusive wolverine threatening trappers in anyway? Trapping amounts to the privatization of a public resource for private gain. Is this what a civilized society permits?
I am most concerned about what promoting this practice of wolverine trapping says about MDFWP priorities. It appears to be more concerned about maintaining the recreational activities of a few people at the expense of the wildlife it is entrusted by the Public Trust Doctrine to protect. It is putting the interests of hunters/trappers ahead of the interests of wildlife they are obligated to protect.
Though MDFWP claims to use the best available science in managing wildlife, it continuously ignores the latest social behavior ecology and conservation biology principles when formulating its wildlife policies with regards to predators, from wolves to wolverine.
Many of the remaining populations of wolverine in Montana are in small isolated island population groups, often as little as 10 individuals in a mountain range. Such small populations are very vulnerable to local extirpation simply to natural stochastic population events. Even the loss of one key individual may jeopardize an island population.
Wolverine bear young in the winter, it’s entirely possible to trap a female and wind up killing her and her young, 2-3 additional wolverine in one swoop because the young starve to death.
In many of these small island population centers there is likely to be only one or two breeding females. If for any other reason, there is additional mortality on any other females–killed by natural causes, being hit by a car or whatever, that population could easily dwindle to zero.
Furthermore, male wolverine by protecting their territories, keep other male wolverine out of the territory occupied by females they have mated with. Thus the presence of the dominant male indirectly protects the young wolverine he has sired that outside males tend to kill. Trapping of a male wolverine may therefore lead to the death of many additional young wolverine.
Given the very low density of wolverine in most of its remaining range, it’s entirely possible for trappers to wipe out the animals from range after range.
There is yet another example of where the MDFWP appears to ignore the latest science regarding the social behavioral ecology and principles of conservation biology. It has to do with the concept of “effective” breeding population. The number of animals involved in breeding in a polygamous species like wolverine, is far less than the total population. Some estimate this breeding population may be as small as 35 animals.
Only a few male wolverine are doing most of the breeding of females, and the number of females that are breeding at any one time is also a subset of the total. Therefore the loss of breeding animals and the loss of entire island populations can put the species at risk of genetic bottlenecks, if the species is not already threatened by such a small breeding population.
There is new research with many other wildlife species that have seen genetic losses; from wolves that recently recolonized Scandinavia; to cheetahs in Africa; to mountain lions in Florida; to wolves on Isle Royal. All have genetic problems because of these kinds of genetic bottlenecks.
At the very least the MDFWP should acknowledge that this may already be a problem with such a very small wolverine population in Montana. Again, there has not been a word from the “professionals” on how many wolverines live in Montana or any of the demographics about these wolverines.
When you’re dealing with an animal that is already precariously low in numbers, and due to its social behavior has limited opportunities for genetic diversity, any losses are serious. Sure there are other sources of mortality out there, but trapping mortality is preventable, most of the others are not.
Most genetic studies that I have seen regarding predators suggest that a minimum effective breeding population of 500 is needed to ensure the long term survival of the species. Obviously, we have already passed below that point with wolverine in Montana.
Whether this minimum number applies to wolverine I do not know, but I suspect the professionals at the MDFWP do not know either, and that is the problem. How can sound decisions be made when the most basic information about the species is not available?
Finally, even the presence of trappers may harm wolverine. Research has demonstrated that snowmobile use of high country can disturb denning female wolverine and cause them to abandon their dens, sometimes leading to the loss of their young. Most trappers today use snowmobiles, so even the pursuit of wolverine may harm their survival.
The precautionary principle in conservation biology is to err on the side of the animal.
If MDFWP wants to portray themselves as “professionals” then it’s time to act like a professional organization, not just a handmaiden to hunters and trappers. MDFWP is the regulatory agency that is supposed to regulate and manage wildlife for ALL PEOPLE and FUTURE GENERATIONS. Unfortunately they appear to be more interested in maintaining archaic traditions like trapping than promoting the long term survival of many species entrusted to their care.
There are many things that MDFWP does well, but the management of predators and endangered species is not one of them. In these instances, it appears that hunter/trapping/economic interests are put ahead of the welfare of the wildlife they have a Public Trust obligation to protect.
I hope in the future I can write a more positive note, one congratulating the Montana Department of Fish, Wildlife and Parks on its willingness to challenge age old dogma.
George Wuerthner is the Ecological Projects Director for the Foundation for Deep Ecology and has published 35 books, including soon to be released Energy: Overdevelopment and the Delusion of Endless Growth.