For Denver and Boulder residents, tomorrow night, CU Wild will host a screening of Wolverine: Chasing the Phantom, followed by a question-and-answer session with a panel of wolverine experts. And me. I’ll be there too. The event will be held at CU Boulder, in Fleming Law room 155, from 6-8pm. It’s free and open to the public. Hope to see you there!
Forrest McCarthy’s film about our Mongolia ski expedition will be showing at the Backcountry Film Festival in Jackson, Wyoming, this Saturday, January 11th, at the Pink Garter Theater. Jason Wilmot will be there for a question session. I may be there, and rumor has it that Forrest himself may make an appearance, fresh from Antarctica.
There will be two showings, one at 5:30 for all ages, one at 8:00 for ages 21+ – presumably the 8:00 showing involves alcohol. (If you really want an immersion experience, I’d suggest vodka shots.) Tickets are $10. Children under 12 are free. Proceeds go to the Wyoming Wilderness Association, which works to protect the wilds of this lovely and inspiring state. You can buy tickets at the door or online. Come see our film, support this worthy cause – and hope to see you there.
(And where have I been for the past month or so? Working on a different writing project, completely unrelated to wolverines; crunching numbers on some of the ski expedition data; trying to find funds to analyze the rest; and planning the coming season in Mongolia. I may start updating again more regularly but it depends on the state of the other writing project, a YA novel about paleontology. Or more accurately, what it’s like to be a really dorky teenager obsessed with something none of your peers can relate to. But I will be back at some point. Thanks for your patience.)
In the previous post in this series, I outlined the major scientific papers that are at the heart of a discussion about both wolverine ecology, and the proposed listing rule. The USFWS is obliged to use “the best available science” in creating decisions for listing under the Endangered Species Act. In this post, I’ll talk about the conflicting interpretations of the papers explored in the previous post, and contentions that each interpretation represents “the best available science.” Those conflicting interpretations create different stories about what is going on with wolverines in the Rockies. Some of the stories clearly justify listing. Others suggest that either everything is fine, or that trapping is fine, or that there’s too much uncertainty out there and we ought to give up on listing because we just don’t know what’s going on. I’ll discuss these stories in a third post.
During the review process, two of the seven reviewers opined that the listing decision was not valid because it was not based on the best available science. Montana Fish, Wildlife, and Parks also submitted comments expressing disapproval of the decision to list and offering arguments that the science used in the decision was erroneous. These different reviews and comments were largely in agreement with each other, but with some significant variations in the scientific arguments that they emphasized, so I’m presenting them individually. The reviews were detailed, and I have summarized them here, so some precision is lost. I apologize in advance for any errors, omissions, or accidental misinterpretations.
Audrey Magoun’s concerns, expressed in edits to the language of the listing decision as well as a separate 33-page analysis, revolve around the fact that there are recorded instances of wolverines denning outside the snow model, denning in shallow snow, and weaning kits prior to the May 15th date used in the Copeland et al 2010 snow model paper. She uses this to argue that Copeland et al, which defines wolverine habitat in the Rockies, is invalid, and that the McKelvey et al 2011 paper, which is based on Copeland et al and is the foundation for the finding that wolverine habitat will diminish, is also therefore invalid. This, in Magoun’s assessment, invalidates the finding that wolverines in the US Rockies are endangered by climate change.
Although she is a co-author on the Copeland et al 2010 paper, she says that at the time of writing, she expressed concerns about the choice of May 15th as the weaning date for wolverine kits – and hence the snowmelt date for the paper. In her analysis of the listing decision, she cites an example of a den found outside the snow model in Ontario, gives a detailed description of the snow conditions in that situation, and then adds examples of den abandonment prior to May 15th to build a case that persistent spring snow (>1 meter depth and lasting until May 15th, as she defines it) is not necessary for wolverines to reproduce successfully. She suggests that the very high fit between dens and the snow model is an artifact of several biases in the data, including a search bias (ie, wolverine researchers look for dens in snowy regions, so this is where they find them) and a research bias (ie, and that most of the published literature is on wolverines in mountain and tundra habitat, leaving out populations in boreal forest regions where the species may behave differently). The critique includes a number of details on how MODIS satellites map snow cover (to argue that wolverines may be capable of utilizing small or remnant snow patches, which may be underrepresented in MODIS data, for denning) and on thermal thresholds for the insulating properties of snow (to argue that thermal cover, or the idea that wolverines den in snow partially to provide insulation and warmth for their kits, would not be necessary at the end of the denning period, when outside air temperatures are warmer, and also to argue that deep spring snow would not be necessary for insulation, since the maximum insulating properties of snow are achieved at 30-50 cm depth.)
Magoun also takes issue with the contention that wolverine dispersal will be inhibited or restricted due to climate change. Her arguments again rest on the idea that the snow model in Copeland et al was inappropriately parameterized and that late spring snow is not the governing factor in defining wolverine habitat. If female wolverines are not tied to snowbound home ranges, this argument goes, then dispersing juveniles will not have to travel farther to establish new home ranges. She points out that wolverines are not restricted to snowcovered areas in order to disperse, and questions whether earlier snowmelt would inhibit connectivity among wolverine population nodes.
With snow dependence and connectivity eliminated as concerns, the argument concludes, there is no justification for listing wolverines as endangered.
Bob Inman’s stance echoes Magoun’s in the assertion that USFWS did not use the best available science to reach the listing decision. He begins with an analysis of a 2007 paper, Aubry et al’s Distribution and Broadscale Habitat Relations of the Wolverine in the Contiguous United States, which looks at historical distribution of wolverines and concludes that the Great Lakes and northeast never (within historical times) harbored reproducing populations of wolverines. The conclusion in the paper supports the idea that wolverines are constrained by snow, since these regions are outside the current snow model. Inman takes issue with this, suggesting that the paper engaged in faulty and circular logic by using historical records to define wolverine habitat, and then using that definition to determine which historical records represent reproducing populations and which represent dispersers. He adds that human interference by the time historical records were being kept (19th century) could as easily account for wolverine absence from the northeast and the Great Lakes as climate constraints. Inman advocates for a food-storage-based hypothesis for constraints on wolverine distribution, as opposed to an obligate snow-denning hypothesis, and by throwing the historical distribution into question, he builds a case for alternatives to the snow model.
Inman then goes on to reiterate a number of Magoun’s arguments about Copeland et al 2010 and McKelvey et al 2011. Inman explicates something that Magoun discussed in broader terms, namely that wolverines may be able to den in small snow patches and that the McKelvey et al paper, in looking at the entire area mapped by Copeland et al as wolverine habitat, failed to assess threats to the areas of the snow map that would be most relevant to wolverine denning – ie, high, northfacing slopes, where all Rocky Mountain wolverine dens have been found to date. In short, he contends that all the snow in the Rockies could melt out during the wolverine denning period with no effects on wolverines, so long as snow remained on these northfacing slopes.
In a 2009 paper, Michael Schwartz and the team at RMRS used genetic analysis to place the US Rocky Mountain wolverine effective population size – that is, the number of wolverines out of the population at large that are actually reproducing - at about 35, with a range between 28 and 50, out of a total population of about 300. This low number has caused concern because it is a very low number, lower than the proposed minimum for long-term persistence of a population on a landscape. Inman suggests that the analysis in the 2009 paper intentionally excluded samples that would have given a higher effective population size. He also points out that we don’t actually have samples from the entirety of occupied or proposed-occupied range in the Rockies, which may also bias the effective population estimates downward. This leads him to conclude that the concern about the low number is misplaced, and not a reason for listing.
Inman then addresses two human impacts on wolverines. The first is infrastructure development, which was ranked of relatively little concern in the listing decision. The second is trapping, which was found to be a secondary threat. Inman thinks that infrastructure development could have greater negative consequences for wolverines than climate change, and suggests that the proposed listing rule dismisses this potential threat without adequate reasoning, citing several studies that show that large chunks of wolverine dispersal habitat are in private ownership and that development could become a problem.
Trapping, on the other hand, is sustainable, in Inman’s view. The crux of this argument rests on determining whether wolverine mortality is compensatory – that is, wolverines that are killed in traps are excess, non-contributing members of the population who would die without reproducing anyway – or additive – that is, wolverine deaths by trapping remove more animals than would normally die, and therefore reduce the population below carrying capacity. Inman argues that trapping in Montana is compensatory, not additive. He looks at two papers that are frequently cited to suggest that trapping mortality is additive (Krebs et al 2004, Squires et al 2007), and refutes them on the grounds of statistics and some behind-the-scenes social factors that, he says, provoked trappers to a sort of revenge trapping frenzy in the study area after being insulted by a researcher’s anti-trapping attitude. He also suggests that survivorship estimates in researched wolverine populations are biased low because much of the research is conducted on “front country wolverines,” wolverines that are more accessible, therefore closer to humans, therefore likely to have higher mortality rates in traps (because trappers, like researchers, aim to make things easier on themselves by trapping in relatively accessible locations.)
Inman also offers detailed comments on the Colorado reintroduction plans and the 10(j) rule. Since those are not relevant to the immediate debate about the relationship between wolverines and snowpack, I’m going to gloss over this for now. He concludes that the rule as written doesn’t reflect the best available science and that conservation actions would be difficult because the decision identifies climate change (which cannot be regulated under the ESA) as the primary threat, while relegating infrastructure, development, and human activities (which can be regulated under the ESA) to a secondary concern, or not a concern at all.
Montana Fish Wildlife and Parks
MFWP criticized the listing rule on the grounds that it represents a repudiation of Montana’s management of wolverines, which MFWP contends has been responsible and conservative. Asserting that the population is healthy and still expanding, they advocate for an “adaptive management” approach that monitors wolverines until the population reaches a threshold that would trigger listing. They cite many of the same arguments and points addressed by Magoun and Inman, but frequently carry these arguments a few steps further. Harking back to the politicized and spurious argument in the 2008 decision against listing, they suggest that wolverines in the Rockies are not a DPS and therefore cannot be listed, since listing under the ESA relies on a determination that the listable population is distinct. They emphasize that the proposed relationship between wolverines and spring snowpack, as put forth in Copeland et al 2010, is simply a hypothesis, not a proven fact, and pluck at a statistical point that Magoun and Inman also reference: the fact that 69% of the dens in the Copeland et al paper were located in areas that retained deep spring snowpack in 6-7 years out of 7, which MFWP interprets to indicate that wolverines den outside of the snow model 30% of the time. They pose Inman et al 2012 as an alternative to Copeland et al 2010, saying that the discrepancies in the snow model can be explained by considering a food-based hypothesis for distribution. They also go so far as to suggest that earlier melt out will benefit wolverines because of increased productivity in wolverine habitat.
MFWP refutes the idea that observed wolverine expansion over the past few decades is the result of a reduction in mortality. It’s not entirely clear to me whether they think that recolonization following extirpation never happened, or whether they are taking issue with the idea that recent reductions in the trapping quotas led to accelerated expansion, but they do state that the listing decision offers no proof that expansion following reduced mortality is a true explanation for recolonization They state that wolverines in Montana are “at or near capacity” to indicate that there is an excess population that can tolerate trapping. They emphasize, repeatedly, that wolverine populations have grown in “…size and distribution, concurrent with declines in spring snow cover and trends toward earlier runoff,” which they equate with conditions that will exist in the future. They also quarrel, however, with the predictive powers of the climate models that were used to determine that wolverine habitat is threatened.
MFWP concludes with the fact that the ESA cannot regulate climate change and says that therefore wolverines shouldn’t be listed, since status under the ESA wouldn’t do anything for them anyway.
What are we supposed to do with all of this information? This is the question that faces decision-makers when they try to interpret science to create policy. Obviously, it’s not an easy task. In the next post, I’ll address the different stories about wolverine ecology that arise from these different scientific analyses, and then discuss the different policy prescriptions that would be appropriate if a given story were true.
In the meantime, a bit of media: here’s a story about the reopening of the comment period which also gives some details on the study in the North Cascades.
And perhaps of note, for the past week I’ve been keeping an eye on wolverine literature published in 2013. This morning I noted for the first time a paper by Inman and several co-authors, with an October 2013 publication date, proposing yet another habitat model and making suggestions for wolverine management at a meta-population scale. I haven’t yet had time to read this paper in detail, but will post more here in coming days, as my schedule allows. For anyone with academic access, the article is available here.
So, what’s going on with the wolverine listing decision and the comment period being reopened? What’s the debate that warrants further comment from scientists and the public? I don’t know what prompted the USFWS to reopen to the comment period, but it is clear that there were disagreements over the science during the peer review and the comment process earlier this year. I’ll make an attempt to summarize the debate as I understand it, starting with the major papers (this post) and then looking at the scientific details that generated discussion (later this week.) Again, I do not know what’s going on, but for people who are interested in commenting, it helps to have a clear understanding of the state of the science. Since the discussion that occurred in the review reflects a bigger set of questions within the science, which I’ve been meaning to address for a while, the reopening of the comments provides an opportunity to look closely at the current state of wolverine research.
For background, remember that wolverines are hard to study; they’re a naturally rare, difficult-to-detect species living, here in the contiguous US, in some of the most challenging terrain in the country. Serious research on the Rocky Mountain wolverine population began only within the past two decades; prior to that, the state of Montana carried out track surveys and tried to monitor the population by assessing trapping take, but, while these activities provided insight into areas of presence, they offered no understanding of demographics or ecology. The scientific literature on wolverines remains comparatively sparse, and we still don’t have good information on demographics in the Rockies. Advocates petitioned to put wolverines on the Endangered Species List in 1994 and 2000; both petitions were denied on the basis of lack of adequate information. A petition denied in 2008 stated that Rocky Mountain wolverines were not distinct from the population in Canada and were therefore not a distinct population segment (DPS) listable under the ESA, an assertion for which there was no published substantiation; there was widespread speculation that this decision was based on the Bush administration’s ideological objections to the ESA. The current proposed rule relies on information that is finally within the body of published science, particularly a series of papers out of the Rocky Mountain Research Station that draw connections between wolverine dependence on snow and cold, and the future threat of diminishing snowpack. A number of other relevant, supporting papers exist, but the RMRS papers are at the heart of the finding that wolverines are threatened by climate change and warrant protection under the ESA. Trapping was found to be a secondary threat, in light of synergistic interactions with climate change. There is very little published information on the effects of trapping on wolverine populations, so this is a tricky topic.
Seven individual researchers participated in the peer review, all of whom are authors on papers that were considered as part of the listing process, and/or who have expertise in other areas. Five of the reviewers (Copeland, Aubry, Schwartz, Squires, and Zielinski) work or worked for the Forest Service; two (Magoun and Inman) do not, having worked more closely with state agencies and with research organizations. All of these individuals are respected scientists with years of experience working on wolverines or, in the case of Zielinski, other members of the mustelid family. The first five reviewers found that the summary of the science and the conclusions reached in the listing rule were accurate and comprehensive, with minor adjustments to technical language. Magoun and Inman, however, questioned the analysis of the science and the conclusion that wolverines should be listed. In addition, the state of Montana submitted comments heavily critical of the proposed rule, and Wyoming and Idaho joined in to oppose federal protection. The alignment of the states against the federal government will surprise no one familiar with the script of carnivore conservation in the West, particularly since Montana was seeking to protect its limited trapping season, which is currently suspended under court order, pending the outcome of the listing decision. The critiques by Magoun and Inman, however, delve into some scientific issues that once again reflect on our limited knowledge of the species.
Here’s the background.
In 2010, Jeff Copeland and a number of his colleagues, including co-authors Audrey Magoun and Bob Inman, published a paper, The Bioclimatic envelope of the wolverine; Do climatic constraints limit its geographic distribution?, that tied global wolverine distribution to late spring snowpack. The paper correlated wolverine distribution with snow that remains on the ground until the period between April 24th and May 15th, proposing that the biological reason for this relationship lay in the fact that female wolverines den in the snow. The paper also suggested that the relationship is obligate – that is to say, wolverines depend absolutely on snow dens, are obligated to den in snow, and cannot successfully reproduce without snow. Despite some fluctuation in observed birth and weaning dates, May 15th represents an approximate date by which wolverine kits were weaned and out of the den, which was why this date was chosen as the upper limit on snowpack persistence. The researchers created a map of snow cover through the use of satellite imagery, incorporating seven years of real-world data on snow cover, and when den sites were overlaid on the map, the match was 97.9%, with 69% of the dens falling within areas that were snow covered for 6-7 years out of 7. Twelve dens (out of 562) occurred outside of the mapped snow cover; the authors stated that these sites were investigated and that they were snow dens, but that the satellites were unable to map the area as snow covered due to canopy cover and the percent of the area that was snow covered versus the resolution of the satellite images. The snow cover map encompassed 89% of telemetry points from wolverine studies worldwide.
The researchers also created a temperature map that looked at regions with maximum August temperatures of ≤ 22º C, and found that 90% of summer telemetry locations fit within this map. This suggested that wolverines could be limited by hot summer temperatures as well as by spring snow distribution. Since these two factors often overlap, especially at the southern edge of wolverine distribution, “….the relative importance of these factors for limiting wolverine range becomes increasingly difficult to assess.” The paper indicated, however, that cold and snow were definitely required for wolverine presence and persistence on a landscape. When I spoke to Jeff Copeland shortly after the publication of this paper, he emphasized that snow denning wasn’t meant to be a single explanatory factor for wolverine dependence on cold, but that it served as an umbrella for numerous other ways in which the species might be tied to frigid environments. In other words, he explained, you could add a bunch of other parameters to the habitat model, but since none of them offered any further refinement to the fit of the model and the data, it would simply clutter things up. As habitat models go, this one was streamlined and very elegant. It was also a clear link, the first in the published literature, between wolverines and climate change.
2011 saw a second paper on wolverines and climate change, McKelvey et al’s Climate change predicted to shift wolverine distributions, connectivity, and dispersal corridors. This paper relied on the 2010 paper to assess the possible effects of a warming climate on wolverine distribution by looking at what climate change would do to snow cover. It predicted that wolverine habitat and dispersal routes would shrink substantially through the 21st century, resulting in further isolation, both geographic and genetic, of wolverines in the Rockies. The bulk of this paper involves interpreting and downscaling global climate models and cross-fitting them to the MODIS data; I’m not going to detail the methods here, except to emphasize that this paper drew on the Copeland et al 2010 paper to reach its conclusions, and looked at the entire area of snowcover mapped in that 2010 paper.
In 2012, Bob Inman and Audrey Magoun, along with colleagues Jens Persson and Jenny Mattison from Sweden, published a paper, The wolverine’s niche: linking reproductive chronology, caching, competition, and climate, proposing several other ways in which wolverines might depend on cold environments to thrive. The paper details wolverine reproductive chronology, assessing cases from research conducted across wolverine range and showing that wolverines give birth across a range of dates, but usually from late January to mid-March, with weaning between April and May. The exploration of reproductive chronology draws connections between food availability and periods of high resource demand for females (pregnancy, lactation) and kits (first summer post-weaning) and suggests that wolverines give birth comparatively earlier than other non-hibernating mammals in order to take advantage of pulses of nutrition at critical times – cached ungulate carcasses see females through lactation and then the kits are weaned in time to take advantage of more varied and abundant summer food resources. The paper also puts forth some interesting hypotheses about competition and food caching behavior – namely that wolverines are able to thrive in a harsh niche because their physiology gives them advantages over other predators, and because they are able to cache and store scarce food resources, since low temperatures preserve meat for long periods of time. Taken together, all of these ideas provide interesting and compelling elaboration on the relationship between wolverines and cold environments – they add texture and intricacy to the broader strokes painted by Copeland et al in the snow map paper. The hypotheses about food storage, reproductive timing, and competition, however, have never been tested. They point to intriguing areas for future investigation, but there’s no evidence, yet, that these relationships are definite.
I’ve never seen these two papers as being in competition or contradiction; they address wolverines’ links to cold climates at different scales, but I’ve always perceived them as complimentary. The Inman et al paper doesn’t explicitly critique Copeland, it puts forth a food-based hypothesis for correlation of wolverine distribution with cold and spring snow. Also perhaps of note in light of the current situation, the first sentence of the abstract of Inman et al reads: “Wolverines are demographically vulnerable and susceptible to impacts from climate change.” There is no quarrel in this paper with the notion that snow is an important characteristic of wolverine habitat, or of the notion that climate change will be a problem for the species. Nor is there a hint of the idea that there must be only one biological reason for wolverines to be tied to cold and snow; food caching at cold sites, snow denning, and physiological adaptations that allow wolverines to outcompete other predators in cold, snowy situations are all part of the same story.
These are the three papers at the core of the discussion. All of them come out of a scientific process that begins with observation and intuition: we know that wolverines are creatures of the north, they’re only found in places that are extremely cold and snowy. Why? The two most important things for survival of any species are resources and reproduction, so the distribution pattern must have something to do with one or both of those factors. How? This is where hypotheses come in, as different scientists come up with possible explanations and test them. It’s also where one of the limitations of scientific inquiry is highlighted: experiments can only test one hypothesis at a time, and two published papers exploring different hypotheses about the same relationship can be perceived as being in competition or offering alternative, rather than complimentary or synergistic, explanations for a phenomenon. Ecology is especially tricky because it’s hard to design experiments and control variables at a scale that will offer conclusive evidence one way or another.
All of this is fine as long as you stay within the realm of dialogue about knowledge, but once you try to pull that knowledge into a decision-making situation that demands facts or truth, you start to run into problems. My father, who is a scholar of the history of science and technology, defines science as a process of human inquiry that makes natural phenomena incrementally more visible to our limited human faculties. It is a pursuit that is fundamentally tied to deep uncertainty and subject to constant revision. It represents our best current understanding of a given situation or process, but it’s never absolute. Unfortunately, in the popular mind science is seen as a way of uncovering Truth, and expressions of uncertainty are seen as negating the validity of an entire hypothesis. Most of the social issues around science – notably the campaigns against evolution and climate science, but also trends in some branches of academia that dislike and wish to discredit science – exploit this misunderstanding. The issue of how far science can generate unassailable Truth or Fact creates tension when we appeal to science to help create policy. That’s where we are right now.
Stay tuned for the next episode, Game of Wolverines, Part Two: A Clash of Analyses
(With apologies to wolverine fans who don’t watch or read fantasy epics, and to any Game of Thrones fans who may have ended up here thinking that this has to do with the actual series. I started watching the show while stuck in Ulaanbaatar for a week with nothing else to do, and I persisted in watching it – truly – because I was trying to figure out whether some of the characters were wearing wolverine pelts as they traipsed around fighting battles. Because mindless books are a great way to spend 24 hours of travel time between the US and Asia, I ended up reading the series to find out what happened, and discovered some wolverine references in there, too. My major preoccupation with these books is wondering how I would design a wolverine research project in a world where winter and summer last for years on end – is it even reasonable to assume that wolverines would persist in such a world, given that a years-long summer would disrupt their breeding cycles and melt out their favorite food-caching spots? I really wish George RR Martin and HBO would address this pressing question.
None of this is meant to draw parallels between specific people and specific characters (since almost everyone in the series is reprehensible), but simply to allude to the complicated human dynamics and loyalties that are at play in any wildlife conservation situation. And also because it affords a fun opportunity to play word games with some of the titles and key phrases from the books. Readers of the books will get the references. Others should just shrug and focus on the content.)
The US Fish and Wildlife Service has reopened the proposed wolverine listing rule for comment. They will be accepting comments until December 2nd; details on submission procedures, as well as access to the proposed rule and associated documents, are available here. If you’re already submitted comments, you don’t need to resubmit them; they are already part of the record. The USFWS is seeking additional information on the following, taken from the published notice:
(1) Whether wolverines are dependent on cold and snowy conditions and habitat that closely approximates the area covered by snow until late spring (May 15).
a. Whether wolverines are dependent on such habitats defined by persistent spring snow for feeding, breeding, and sheltering.
b. Whether the projected impacts of climate change will result in loss of habitat for wolverines.
(2) The factors that are the basis for making a listing determination for a species under section 4(a) of the Act, which are:
a. The present or threatened destruction, modification, or curtailment of its habitat or range;
b. Overutilization for commercial, recreational, scientific, or educational purposes;
c. Disease or predation;
d. The inadequacy of existing regulatory mechanisms; or
e. Other natural or manmade factors affecting its continued existence.
(3) Information regarding the threats we identified in the proposed rule, or threats to the species that we may have overlooked in the proposed rule. Threats we identified were:
a. Habitat loss due to climate change;
b. Regulated trapping of wolverines and trapping of wolverines incidental to trapping for other species; and
c. Inbreeding and related genetic and demographic effects of small and isolated populations.
What happened to prompt the reopening of the comment period? It seems that in the process of the peer review that is required for proposed listing rules, conflicting scientific interpretations of the parameters of wolverine dependence on cold and snow emerged. The full documents of the different peer review parties are available, and for anyone who wants to understand how scientific debate happens, and how complicated the translation of science into wildlife policy actually is, these are worth the read. For many people, though, several hundred additional pages of very detailed information on how a MODIS satellite works, and the variation in wolverine parturition dates, and whether or not a given climate model is reliable, will probably be overwhelming. I’m cautious about taking on this discussion, but I do want to provide an overview to readers who don’t have the time to delve into all of these documents. I also think that this provides an instructive moment to reflect on what science is, what it can (and cannot) do in terms of helping us make decisions, and how it operates when it gets tossed into an arena of competing interests. I’ll deal with both of these questions later this week, in installments, in order to avoid the deadly sin of a 6000-word blog post.
For now, though, a quick note: my understanding, based on reading the peer reviews, is that the debate is about the snow model, the genetics, climate modeling, whether or not wolverines actually do depend on snow to den, and whether or not that dependence is the only explanatory factor in describing wolverine distribution and constraints. Less prominent in the discussion are trapping, incidental take, motorized recreation, or any of the other hot issues that provoke strong opinions, although some parties do, predictably, defend limited trapping. It’s possible that USFWS reopened the comment period in order to gather more information and give scientists the chance to resolve the debates about interpreting the published literature. It’s also possible that they reopened it because other scientific papers that might shed light on the questions are due for publication, and they want the opportunity to enter these papers into the record. I’m not sure. But I don’t see this as an invitation to push any opinions that lack very solid and credible science to back them up. Anyone with relevant information should comment, but at least glance through the peer reviews to get an idea of the debate and the competing arguments; it’s probably most constructive to target your comments and your evidence to those issues.
Earlier this fall, I helped Forrest McCarthy, one of the biologists on the Mongolian ski expedition in April, put together a short film for the 2013-2014 Backcountry Film Festival. This film festival is run by Winter Wildlands Alliance, and celebrates human-powered winter recreation (or, as I think of it, people getting in touch with their inner wolverine.) The film was accepted, and will be touring the country, from Alaska to Vermont, with opening night at the Egyptian Theater in Boise, Idaho, on November 1st. Tickets are $10. Details are available at the festival’s website. So is a trailer that features clips from our film – viewers will be able to tell, instantly, which clips are ours, since they’re the only ones featuring yaks. This is the first festival film that I’ve been involved with, so I’m pretty excited!
Forrest is a well-known guide, an advocate for human-powered winter sports and for wilderness, who has a long history with wolverine research; he worked with the WCS project when it was running fieldwork in the Tetons, and has orchestrated several citizen science projects since then. He maintains a great blog about his backcountry adventures, and has made a number of films, including a previous short film compiling video from our trip. His presence on the ski trip was a tremendous asset, and Mongolia clearly worked its magic on him, as his ongoing interest in the Darhad demonstrates. All of the filming and the editing are his work; I adapted a script that he wrote, and I narrated, since the script contains Mongolian terms, and Mongolian is a language that will tie the tongue of anyone who hasn’t lived there for a few years. The focus is on the sense of restlessness and the big quest that drives those of us who go out looking for wolverines, rather than on the details of the science (I’m saving that for another film…..and several upcoming papers.) So check the calendar, and show up prepared for big adventure in search of wolverines.
For Montanans who just can’t wait for two days to indulge a thirst for wolverines onscreen, Montana PBS will be airing Wolverine: Chasing the Phantom tonight at 7 pm – always good for a little inspiration as the winter weather sets in and we head into ski season.
Scandlynx, the program that monitors lynx and wolverine in Scandinavia, just issued a report on the status of the Norwegian animals that they tracked over the past year. The report is in Norwegian; readers are welcome to have fun with google translate, which will inform you that in Norway, wolverines are lured into “cubicles” to be fitted with GPS “necklaces” – maybe only the linguistically-obsessed among us find this amusing, however, so I’ll summarize the report here, in English, with a bit of background information. Caveat: I don’t speak Norwegian, and internet translation is always subject to oddities, so don’t hold me to the specifics.
Wolverine and lynx in Norway and Sweden present a unique problem that we fortunately don’t have to deal with here in the US; large herds of domestic reindeer are a major food source for these predators, generating correspondingly high levels of animosity from reindeer herders. Herders receive compensation for losses in both Sweden and Norway, but the compensation takes different forms; in Sweden, herders are paid a flat (and very high, somewhere around $20,000) rate for each successful wolverine den within their herding territory. In Norway, the compensation scheme is similar to our own wolf depredation funds in the western US; herders are given payments per animal on the basis of a confirmed kill. In an argument that precisely parallels arguments from ranchers here in Montana and Wyoming, reindeer herders claim that for each confirmed kill, several others go undetected, and that they are therefore being under-compensated for their losses.
In 2011, the report says, the Norwegian Environment Directorate commissioned a study on the rate of depredation (“murder rate,” according to google, which probably accurately summarizes how the herders feel about it) to try to clarify the actual loss of reindeer to lynx and wolverine. The study covered provinces in central and northern Norway, and will continue for five years. There’s also a component that looks at territoriality of lynx family groups, and a component that tracks collared female lynx and wolverine. The project is tied explicitly to management outcomes, and also considers the effectiveness of current monitoring protocols. The current report is preliminary, not a final report.
Researchers dart animals from helicopters, collar them, and then, with the input of knowledgeable locals, set up a series of stations or traps (the aforementioned “cubicles”) which the animals visit. During the first year of the study, four lynx and 11 wolverine were collared and tracked. The GPS transmitters were set in an intensive mode for a particular period of time, with fixes taken at one hour intervals, in order to determine predation by looking at places where the animals lingered.
The lynx had huge home ranges – 2800 km2 for one of the females, 4200 km2 for one of the males – and seem to be making a living primarily off of roe deer and domestic reindeer, supplemented with the occasional moose calf and some small game (hare, the prey species we most commonly associate with lynx here, comprised only a small part of the diet of these four animals.) The lynx killed six adult and nine calf reindeer, as well as three reindeer classified as “unknown.” These kills occurred throughout the year.
Seven of the 11 wolverine were monitored with the intensive GPS, six wolverine (all male) during the winter, and three (one female, two males) during the summer. The six male wolverine killed between four and six adult reindeer (there seems to be some uncertainty about the status of two of the kills) and three calves during the winter. No depredations were recorded during the summer. Wolverines relied much more heavily on scavenged and previously stored carcasses. The female was recorded killing a roe deer and a bird during the summer, while one of the males added bird and hare to his diet. The researchers specify that they are unsure whether some of the carcasses visited by wolverines in the winter might have been wolverine kills stored away before the study began.
This work is interesting because the researchers are considering some intriguing, landscape-scale systems questions – predator interactions, human landuse, social tolerance, and management and policy issues. It will be interesting to follow the work as it progresses, to see how management and compensation rates change, and to look at how this does or does not increase tolerance for carnivores on the landscape.
If you’re truly obsessed and/or have a lot of time on your hands, you can allegedly track some of the animals in this study here. There is an English version of the page as well. You will have to register, but the process seems to be open to anyone. I still haven’t been able to find the wolverines, however, even after selecting the wolverine project and selecting specific wolverines. So have fun, and if you figure it out, let me know.