For your reference, here is our cast of wolverines:
F3 – A 3-year old female inhabiting the Absarokas in Montana, north of Yellowstone National Park. She was collared and instrumented in 2007. Although she is of reproductive age, she has not yet – to our knowledge – had kits. She lives in a region where trapping of wolverines is still permitted, and many wolverines have been trapped out of this area over the past few years. There is a resident male in her territory (M57); he moved in in spring of 2009 and we’re hopeful that there will be kits this year.
The Menan Male (M57) – A young male inadvertently caught in a bobcat trap in Menan, Idaho, in spring 2009. WCS transported him to more suitable wolverine habitat in the Centennials, but he promptly took off to the east, settling in the Absarokas in a territory that overlaps with F3’s. The fact that he established a territory here indicates that there was an unoccupied niche for a male in the northern Absarokas – which could explain why F3 apparently failed to produce kits in 2009. We’re hopeful for 2010. M57 was recaptured in a log box trap in February 2010. He was fitted with a collar, checked for fitness, and released. F3 was with him when he was captured, as shown by the trap’s cameras, and the two were picked up within a half mile of each other two days before the capture.
M2 – An older male whose territory encompasses the most remote region in the Lower 48– the Thorofare, more than 30 miles in any direction to a road. M2 was captured, collared, and instrumented in 2005. His territory overlaps with that of F133 and, potentially, the Hypothetical Female.
M4 – A young male first sighted in summer of 2006 in M2’s territory, where he left enough hair in his footprints across high-altitude snowfields for us to collect a viable DNA sample. He was captured, collared, and instrumented during the 2006-2007 winter field season. He disappeared entirely from the radioscape a few weeks after he was instrumented, in March of 2007. When the California wolverine was sighted in spring of 2008, researchers flew the Sierras on M4’s frequency, but didn’t pick him up. His fate remains unknown.
F133 – A 3-year old female born in the Gallatins in Montana. She was captured and instrumented by the Wildlife Conservation Society’s wolverine project before traveling southeast across Yellowstone to the Thorofare region. Her territory overlaps with M2’s, but so far there is no evidence that she has had kits.
F404 – F404 was instrumented in 2002 by the Wildlife Conservation Society. Her territory encompasses a portion of the Tetons, and in 2004 she denned in one of the west-side canyon, the first – and to date, only – documented wolverine reproduction in Wyoming. Her daughters, F405 and F421, were captured and instrumented in May of 2004.
F405 – Daughter of F404, she ventured south to the Palisades before returning to the Tetons. The death of another Teton female in 2002 may have opened up enough space in that range for F405 to make a territory for herself.
F421 – Daughter of F404, she was born in the Tetons in 2004, spent 2005 traveling between the Tetons and the Wyoming Range, and in 2006 settled in the Wind River Range outside of Pinedale, Wyoming. She is the only documented resident wolverine in the Winds.
The Hypothetical Female – She may or may not exist, and evidence for her existence is based primarily on absence. F133’s territory runs up against an invisible line, a single drainage in the southern Absarokas that F133 never crosses. In spring of 2009, M2, whose territory encompasses F133’s but also stretches beyond that to include the region F133 refuses to enter, seemed to restrict his movements around a drainage in this region. He could have been motivated by a rich food source in the area, but he could just as easily have been visiting and marking the den of a female whose kits he fathered. Further anecdotal evidence for this female includes the capture of a yearling male wolverine, the Lava Male, just off Togwotee Pass – in M2’s territory – in January of 2009. DNA analysis could prove that he is M2’s son, in which case – because we know that F133 only reached reproductive age this year – there must be a second female. On the other hand, the Lava Male might just have been wandering through this area.
The Lava Male (M56) – A yearling male captured off Togwotee Pass by WCS in January of 2009. He spent several weeks bounding between the pass and the DuBois region, before heading to the southern tip of the Wind River Range. He stayed there for a few weeks, and then took off to the south. In April 2009, he was documented in the Green Mountains just north of Rawlins, approximately 90 miles from the Colorado border. On June 1, 2009, he crossed the border, becoming the first confirmed wolverine in Colorado since 1919.
Stormy, Iceman, and Zed – Three wolverines camera-trapped in the Wallowa Mountains of Oregon in 2011. Stormy and Zed are males, and Iceman is probably a male as well. Are they residents, or just dispersing through the range? Ongoing camera work will determine whether they are there to stay; the research will also look for evidence of female wolverines in the range.
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Do you know where M56 may have crossed I-80 and eventually into Colorado? What was the terrain and vegetation like in that area?
I’d suggest getting in touch with the Wildlife Conservation Society about this – it was their collar and I think they tracked him pretty closely on his journey south. Interestingly, I understand that on a broad scale his route closely followed a least-cost-path model for wolverine dispersal, published a few months before M56’s trip, by Mike Schwartz of the Rocky Mountain Research Station. Basically, the model suggested that a wolverine would follow the highest ground through Wyoming towards Colorado, and this is essentially what M56 did. That paper is available here: http://www.treesearch.fs.fed.us/pubs/34072
We have sighted what we believe to be a wolverine. It was located on the Taggert Lake Trail in the Grand Tetons National Park. I have some exceptional photos. Please contact me via email and I will provide more information on time and exact location. My family and I believe this was the most amazing part of our trip to Wyoming.
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How about leaving these animals alone? There are so many wolverine studies going on that every wolverine in the U.S must have a collar on. It is intrusive and is a prime example of studying animals to death. Use camera traps and stop handling these wild animals.
Larry, thanks for the comment. In case you did not see my response to your previous comment, I am reposting it below. It clarifies to some extent the different information that can be obtained via collaring vs. non-invasive methodology, and why occasional invasive research remains necessary.
Believe me, we do not have a collar on every wolverine in the West. If we did, we would know EXACTLY how to protect them, and that is the ultimate goal.
Regards,
Rebecca
“Thanks, Larry. I don’t know a single wolverine biologist who’s happy with the idea of “messing” with the animals. Thus far, given technological constraints, the only way we’ve been able to learn enough about the species to conserve it is to take some fairly invasive steps in order to keep track of the animals. I want to clarify that these are not just radio collars. They are GPS collars, which record information at very fine scales. The questions that these collars allow us to answer are likewise fine-scale questions about habitat use, territoriality, energetics, feeding habits, and reproduction. We trap for about three months a year, and the wolverines hold their collars for a few weeks to a few months at most. The amount of information that we obtain from this brief intrusion into their lives is huge. Nevertheless, I am sick to my stomach every time we have to handle an animal, and all the wolverine biologists I know experience a similar degree of worry over the well-being of the animals. We are required by state governments and our funders to pass stringent tests on handling methodology to make sure that the procedures are both safe for the animals, and justified by the need for information.
There is currently an intensive effort underway to shift to non-invasive methodology (camera-trapping, hair-snaring for genetic monitoring, etc.) In an ideal scenario, population monitoring and large scale questions will, in the future, be answered purely through non-invasive means, with collaring reserved for finding answers to fine-scale questions that can’t be answered through genetic monitoring and camera trapping. This is the approach I’m taking in my wolverine work in Mongolia, precisely because I don’t want to stress the animals. It’s also cheaper and technologically more appropriate to the situation.
I definitely understand the urge to just leave nature alone and let it function on its own. Unfortunately, though, given the degree of human encroachment on the ecosystem, and the extent to which even remote events (carbon emissions….) can have huge effects on local wildlife populations, leaving a wildlife population alone is no longer enough to ensure that it will be okay. There are some questions that can only be answered through research, and sometimes that research does involve invasive methodology. No one is happy about that, trust me, but if it answers questions that allow us to manage the species and landscape to better conserve them, then the payoff is worth it. I want these animals to survive and in order for them to do that, we have to understand their needs.
I hope that our society one day gets back to a point where ecosystems can function fully and we can trust that all species will survive if left to their own devices.”
To what extent is “climate change” endangering wolverines, relative to human encroachment, habitat destruction, hunting, trapping, poisoning, etc? Some people say anthropogenic global warming (AGW) is the biggest threat, but it wasn’t AGW or climate change that wiped out most of the wolverine populations in the lower 48 states. Maybe it is now, but it’s not what is threatening to put them on the endangered list.
If I even question whether AGW is the biggest threat to wolverines, some people completely fly off the handle with the old “the science is in, there is no more room for debate!”
Can you shed the sweet light of reason on this?
Thanks for the comment, Jim. It’s a good question. I’ll give a brief summary below, but this is off-the-cuff and by no means represents anything that should be used in any legal or scientific situation. It’s the overarching narrative, and it deals only with wolverines in the Lower 48 in the US. I notice that you seem to be from Canada, so I’d need to brush up on gulo trapping regulations there before I could weigh in on how this story might or might not differ in Canada.
To the best of our knowledge, wolverines were pushed back and pretty much extirpated in the contiguous US due to a combination of trapping and, perhaps more devastatingly, poison-baiting intended for other carnivores (primarily wolves) in the first half of the 20th century. A few pockets of population held out in Montana and Idaho but these were probably dependent to a greater or lesser extent on dispersers from Canada. So yes, you are correct in saying that climate change was not what originally wiped out wolverines in the US Rockies.
By the turn of the millennium, wolverines had repopulated most of the ranges in Montana and Idaho, and started to make their way back into long-vacant territory in Wyoming. They are currently continuing to expand their range (eg, M56 in Colorado, and possibly the male in Sierras of California, if he is not a released captive), so we have a unique situation, in which a species is simultaneously appearing to make a comeback while also facing an inescapable long-term threat. That is, indeed, climate change, but I’ll go through the effects of the other threats that you mention first.
Habitat encroachment is not really a threat to wolverines in the Lower 48. There is so little overlap between large-scale human activities and wolverines that the effect, in and of itself, is negligible. Disturbance by backcountry use is likewise of uncertain import; it’s possible that snowmobiles and/or backcountry skiers could disturb denning females, but again, if this happened once in a while among a widespread and robust population, it probably wouldn’t constitute a large-scale threat.
Poison bait for predator control is outlawed in all states where wolverines currently have breeding populations. The only real risk would be accidental poisoning, and we are not aware that this is a major problem for wolverines.
Infrastructure is probably an occasional source of mortality. We do know of several wolverines that have been hit by cars, but we also know of a number that have successfully crossed roads and, in a few cases, major highways. This isn’t something to be complacent about, but, again, it’s probably not going to drive wolverines to extinction.
Montana is the only wolverine-occupied state that maintains a trapping season, currently limited to a take of 5 wolverines statewide: three in one region, two in a second, and one in a third, with a female subquota of one in each region that permits the take of more than one animal. This means that once a female is trapped in either of those regions, the season closes for that region, regardless of how many wolverines have been taken.
There are currently no studies that definitively say that trapping in a fragile meta-population is a threat, although there’s plenty of evidence derived from what we know from other studies. The bottom line on trapping is that, over the long term, it probably is an issue for wolverines in Montana, because wolverines are highly territorial, require huge expanses of space for each adult territory, have an incredibly low reproductive rate, and must disperse over huge distances to reach suitable vacant territories. In instances where a small-ish mountain range supports only one or two reproductive females, knocking out even one of those animals constitutes a major setback for the population. To the extent that Wyoming and, by extension, Colorado rely (or will rely, if the CO reintroduction plan goes forward) on dispersers from Montana to maintain their populations, Montana’s trapping season could have repercussions for much of the Rockies. This is speculative, however, and the most direct impact is certainly on Montana.
Each of the items above constitutes or has constituted a threat to wolverines on some level but, with the exception of trapping, none of them probably have the ability to push wolverines into extinction. Acting together, however, they add up to a set of considerable, albeit not insurmountable, challenges.
Which brings me to climate change. Wolverines are irrefutably climate sensitive and dependent upon snow and cold. (see https://egulo.wordpress.com/2010/05/22/south-of-54-the-bioclimatic-constraints-of-wolverines-on-the-edge/ for a summary of the research on this topic) so, in a sense, the people you refer to are correct: the science is in, and the biggest threat facing wolverines is climate change. It’s not what reduced the population originally, but, again, we are dealing with an apparent comeback and range reoccupation, so whatever the original drivers of wolverine extirpations, the threats that you mention are not overwhelmingly problematic to the population.
Climate change can be thought of as an amplifier to the set of challenges discussed above, because it adds another set of issues (substantial reduction of denning habitat, increase of summer temperatures, and greater distance required to disperse) to direct mortality and disturbance. In a species like wolverines, especially at the southern edge of their range, I don’t think that the cumulative effects of these problems are linear; I think that they are exponential, and climate change will be the driver that makes relatively-easily-addressed issues of in situ mortality and disturbance into a population-level disaster. This was the conclusion of the US Fish and Wildlife Service’s listing decision in December of 2010 (summarized here: https://egulo.wordpress.com/2010/12/15/gulo-gulo-warranted/)
In terms of how we address this threat, our only option is to preserve widespread populations on the landscape and do our best to ensure connectivity. In effect, this means addressing the very set of problems that you asked about and that I discussed above. This is the first line of action and, since Americans lack the will to address the drivers of climate change, our only course is to try to buffer the population against the effects of a warming world.
As a note on Canada, the review of the science for the US listing decision states:
” Since European colonization, a generally recognized range contraction has taken place in boreal Ontario and the aspen parklands of Manitoba, Saskatchewan, and Alberta (COSEWIC 2003, pp. 20-21; Slough 2007, p. 77). This range contraction occurred concurrently with a reduction in wolverine records for the Great Lakes region in the contiguous United States (Aubry et al. 2007, pp. 2155-2156). Causes of these changes are uncertain, but may be related to increased harvest, habitat modification, or climate change (COSEWIC 2003, pp. 20-21; Aubry et al. 2007, pp. 2155-2156; Slough 2007, pp. 77-78). Analysis supports climate change as a contributing factor to declines in southern Ontario, because snow conditions necessary to support wolverines do not currently exist in the Great Lakes region of the contiguous United States, and are marginal in southern Ontario (Aubry et al. 2007, p. 2154)
Wolverines in western Canada and Alaska appear to persist everywhere that habitat and climate conditions are suitable (COSEWIC 2003, pp. 13-21; Aubry et al. 2007, pp. 2152-2155; Slough 2007, p. 79; Copeland et al. 2010, Figure 2). Throughout this area, wolverines are managed by regulated harvest at the Provincial and State level. Population estimates for Canada and Alaska are rough because no wolverine surveys have taken place at the State or Provincial scale. However, the population in western Canada is estimated to include approximately 15,089 to 18,967 individuals (COSEWIC 2003, p. 22). The number of wolverines in Alaska is unknown, but they appear to exist at naturally low densities in suitable habitats throughout Alaska (Alaska Department of Fish and Game 2004, pp. 1-359). We have no information to indicate that wolverine populations have been reduced in numbers or geographic range in Alaska.” – (USFWS 12-Month Finding on Petition to List the Wolverine; http://www.federalregister.gov/articles/2010/12/14/2010-30573/endangered-and-threatened-wildlife-and-plants-12-month-finding-on-a-petition-to-list-the-north#p-31)
Overall, if you’re looking to understand exactly what the science says on threats to wolverines, the USFWS listing decision cited above gives a great overview of the most current studies, and, since the decision does conclude that climate change is the big threat, and the reason that wolverines are warranted for protection under the Endangered Species Act, it also gives a good explanation of the rationale behind the statement “wolverines are endangered by climate change.” It’s 134 pages long, but if you want a much more thorough and defensible assessment, I point you to the decision.
Hopefully that helps resolve the question. Let me know if you have any others.
Thanks for your very reasoned response – it’s given me much food for thought. It seems the wolverine population in Glacier National Park is at the tipping point. http://www.humanesociety.org/news/magazines/2011/03-04/spirit_of_the_wolverine.html
Relatively small changes in their environment can have major impacts, so in that respect, climate change certainly can’t be ruled out.
Here’s something I found in my research:
“During the Mackenzie Valley Environmental Review Board (MVEIRB) Technical Sessions for De Beers Snap Lake Diamond Project in Yellowknife in January 2003, it was pointed out by RWED Government of Northwest Territories, Department of Resources, Wildlife and Economic Development) that between 1998 and 2002, 16 wolverines had been killed or removed from mines in the Lac de Gras area. De Beers acknowledged that snow track surveys were a poor method for determining wolverine abundance, a method that was also used at Snap Lake. Clearly snow track studies of wolverine tracks are not good indicators of wolverine populations; they are only indicators of wolverine presence. Further, it was acknowledged by BHP (Broken Hill Proprietary, one of the world’s largest mining businesses) that the loss of 16 wolverines represented a cumulative effect on the local population. Wolverines had been seen one three separate occasions at the domestic landfill, and one had become so desensitized to human presence that not even bear bangers or rubber bullets could drive it off. Eventually, it had to be live trapped and destroyed. Although no direct link could made between the wolverines seen at the landfill and the wolverine that was destroyed, the possibility that the landfill may have contributed to the of the wolverine cannot be dismissed (BHP 2002).”
This is an animal with a home range that may be 900 km² or more (MULDERS, R. 2001).
I don’t know if this is a sustainable loss, but it could be an example where a healthy population of wolverines is decimating by mine development in the North, to the point that climate change can become a limiting factor. I’m no expert, but it seems to me that the impacts that human encroachment and all of its ramifications are more manageable than something as ill-defined and long-term as climate change.
well said, Rebecca! agreed, Wolverines are cold climate experts. agreed, global warming. but ice age short cycle is 40k years, we are 14k years into. much of it is beyond human influence.
Thanks for the comment. As I’ve said before, I don’t debate the reality of anthropogenic climate change on this blog. I’m a science- and reality-based individual, hence so is this blog. But it is not true in this case that “much of [current climate change] is beyond human influence.” Obviously there are background shifts in climate, but the current warming trend is unprecedented (including within the context of what we know about the complexities of ice age cycles, which suggests that we should now be in a cooling period) and is linked to excess carbon dioxide in the atmosphere, which is the driving mechanism of climate warming. When do we note the signature of this excess carbon dioxide entering the atmosphere? At the onset of the Industrial Revolution, when we started burning fossil fuels in vast quantities. So it’s us, whether you want to face that truth or not. I don’t entertain this discussion here because the science is very clear. Before engaging any further here, here’s a primer on arguments against anthropogenic climate change, which pretty much summarizes how I’d respond to anything you come up with: http://grist.org/series/skeptics/ The stuff on Grist is pretty basic, so I’d also suggest that you read the science if you have further questions.