Game of Wolverines, Part Two: A Clash of Analyses

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

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

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.

Wolverine Stories

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.



Game of Wolverines, Part One: Is Winter Coming? And Why Does it Matter?

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.)

Wolverine Proposed Listing Rule Re-opened for Comment

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.



Quick Summary of Listing Rule, and Press Rundown

In (very) brief, and with promises of more detailed discussion to come: the 127-page proposed rule for listing wolverines as threatened under the ESA warrants an attentive reading by anyone interested in the species. The introduction summarizes the state of the science and discusses how and why weight is given to certain studies, and in and of itself, this is valuable to consider. For those who are just looking for the major points, though – wolverines are threatened due to climate change. Reduction in suitable denning habitat, which is projected to contract by up to 63% in the coming decades, is of major concern, but the synergistic effects of climate change and other threats – notably, trapping in Montana – are also referenced. While acknowledging that trapping has not provided a serious threat in the past and probably wouldn’t in the future in the absence of climate change, the rule states that ongoing trapping in Montana is not viable for wolverines, especially when inadvertent take and by-catch are taken into consideration. Recreation, including snowmobile use, is not deemed to be of concern. A reintroduced population in Colorado could substantially bolster the Rocky Mountain population and increase genetic viability over the long term, but this population would be given 10(j) status as an ‘experimental, nonessential population,’ to reduce management conflicts. The comment period on the proposed rule is open through May, and the USFWS seeks input from people with scientific knowledge and meaningful contributions to an understanding of management challenges. In a single paragraph, that’s the gist of the rule.

The circulation of the proposed rules for wolverine listing have generated a flurry of press – this is just a rundown for people who are interested in keeping up with what’s being written. At 10:00 this morning, there were three news articles on wolverines listed on Google; at 8:30 this evening, there are 233. That’s probably more press than wolverines have gotten in a single day, ever.

The official US Fish and Wildlife Service press release summarizes the rule and its implications. A summary at OnEarth Magazine of wolverine conservation is a good overview of the situation, with some quotes from Jeff Copeland, although the article is in serious need of some copyediting (punctuation issues lead the piece to suggest that sheep are carnivores, and that wolverine populations are greater at the southern edge of their range, and – most entertainingly – Gulo gulo is stated to mean “glutinous glutton,” which leads to images of wolverine-shaped loaves of bread.) The Huffington Post and Fox News (You can search it on your own; I refuse to provide a link to this outlet, even if they are covering this story), published an AP article detailing the rule and featuring commentary from various wolverine and legislative authorities, discussing both the potential reintroduction to Colorado, and the fact that the decision cannot be used to regulate greenhouse gas emissions despite the fact that climate change is the primary threat. This piece has appeared in papers in Canada, across the US, in the Guardian in the UK, and as far abroad as New Zealand.

The announcement earned an article in the New York Times, and a mention on the New York Times energy blog, a full piece on Reuters (and also on Reuters’ UK site), and an article in the Los Angeles Times. In wolverine territory, the AP piece appeared in regional newspapers through Wyoming, Montana, and Idaho. The Jackson Hole News and Guide put together a good piece that touches on the issue of the poorly-known wolverine population in Wyoming, the status of gulos in the Tetons, and possible avenues by which the Colorado reintroduction would proceed. The Great Falls Tribune has an article that highlights statements from Montana Fish, Wildlife, and Parks regarding trapping – tentatively, and reading between the lines, it suggests that they are going to take their stand around wolf trapping, defending it against concerns about incidental take of wolverines, rather than around wolverine trapping itself, but we’ll see what happens. The Yellowstone Gate, featuring news from Yellowstone and Grand Teton National Parks, has a piece that details the times, dates, and locations for a series of public hearings on wolverine listing that are part of the process of finalizing the rule. In Idaho, the Spokesman Review has a blog post on the decision.

In Colorado, several pieces of press have appeared recently in the Summit County Voice, including a piece last week that highlighted the interconnected concerns of wolverines and the ski industry, and a piece today featuring commentary on the rule and the proposed reintroduction. Another short piece appeared at Aspen public radio, focusing primarily on the reintroduction prospects. The Durango Herald has an article about the proposed reintroduction too.

Washington state has cultivated its enthusiasm for wolverines with several pieces over the past few weeks, including this one, in the Seattle Times, discussing the rebounding wolverine population in the Cascades. This article features another video of a growling wolverine in a trap. The foamy drool in the video is pretty typical of wolverines in traps, so don’t worry that the animal is rabid.

Finally, from several weeks ago and not at all related to today’s decision, there’s a great Alaska Dispatch piece on wolverines in Chugatch State Park. If only we all lived in places where our state parks were big enough and cold enough to host a population of wolverines.

I’m sure that the press coverage will continue to snowball, and I will try to keep up. Let me know of any other pieces that I’ve failed to post. I’m out in the field for the next few days but will try to post a few thoughts here soon.

Proposed Listing and Reintroduction Rules Available

Although it won’t officially be entered into the Federal Register until Monday, the proposed rule to list wolverines as threatened under the ESA is now available in .pdf format on the Federal Register website. Accompanying this proposed rule is a second proposed rule regarding experimental-nonessential status (10j, in short form) for reintroduced populations in Colorado, Wyoming, and New Mexico.

I’m currently reading through these documents so my analysis is not yet available – I’m initially confused by the inclusion of Wyoming in the 10j rule, since there are breeding populations there, but I’ll wait to say anything until I’ve actually read the full rules. Stay tuned, and in the meantime enjoy reading them yourselves.



A Question of Scale

Two weeks ago, Montana Fish, Wildlife, and Parks and the coalition of environmental groups who sued the state to end wolverine trapping withdrew from a hearing that was scheduled for January 10th, after the USFWS indicated that they will recommend wolverines for listing under the ESA. This meant the total closure of the 2012-2013 trapping season and, pending the ESA recommendation, possible closure of wolverine trapping in Montana until the species recovers. The relief among wolverine enthusiasts, advocates, and researchers was tempered by Montana’s announcement that they will pursue an exemption if the species is listed, in order to continue to trap. Presumably, the legal argument for an exemption comes from the fact that, in the 2010 “warranted but precluded” decision, climate change is listed as the primary threat, with trapping as a secondary factor. Advocates issued responses (here and here) condemning Montana’s decision and deriding MFWP for “brash intransigence” and for making politicized decisions that ignore the “best available science.”

While all of this has been unfolding, I’ve been involved in some wider discussions, and some private consideration, about what science is, what it means when an individual claims to do science or to be a scientist, and the consequences of granting prestige to ‘science-based decision-making,’ especially in a culture where scientific literacy remains hazy. I could take this post in several directions, all of which I hope to eventually address on this blog, but I am going to focus here on the immediate questions at hand: What is going on with these competing claims about managing wolverines based on the “best available science?”  What is the “best available science?” And is it possible that no one is incompetent in this scenario, and that two sets of science, with evidently conflicting results, are both correct?

Here’s the background – MFWP contends that it has managed wolverines and continues to manage wolverines based on ‘sound science,’ and that years of data from track surveys and from carcasses turned in by trappers suggest that the population is healthy enough to bear the low levels of mortality caused by trapping (the current season is set at five individuals, with a female subquota of three.) They claim that wolverines have continued to expand their range despite a season that until a few years ago had no quota. They are also defending a methodology that they developed at a time when no one else was keeping track of wolverines at all and when there was very little precedent – or technology – available for more sophisticated studies. This methodology was applied, and apparently worked, for decades, and institutions are slow to change systems that have worked.

Over the past 15 years, however, a set of studies, funded and implemented by federal agencies (including the Forest Service and the National Park Service) and non-profit research organizations (including my host institution, the Northern Rockies Conservation Cooperative, as well as the Wolverine Foundation, the Wildlife Conservation Society, and a number of others) have employed much more sophisticated technology and analytical methods to investigate wolverine populations in the Rockies. Many of these studies have been based primarily in Montana, but they have also documented reproductive wolverine populations in Wyoming, Idaho, and the Cascades, and dispersers as far abroad as Colorado, California, and eastern Oregon. These studies suggest two things: the wolverine population in the western US is indeed continuing to expand, and it is also under threat from shrinking snowpack as temperatures increase in the face of climate change. Taken together, the research from both MFWP and these wider studies paints a striking and complicated picture: a story of a species that is poised at a tipping point between a triumphant, unassisted return to habitat from which it was extirpated a century before, and a coming century in which the species might suffer a second extirpation, much more final than the last. These stories both seem to be true, and like everything else about the species, the conservation debate is therefore uniquely challenging.

Both sides of the discussion want to default to well-worn arguments: the advocates claim critical danger (in some cases, erroneously, because of ‘declining populations’) and the pro-trapping managers claim that the rebounding population indicates that there is no problem with removing such a small number of animals each year. I obviously am a biased individual in this debate, and those biases run too deep for me to be truly objective, but I hope that I can make an honest attempt to illustrate why we need to push for a different understanding of conservation when we think about wolverines, and why that understanding can encompass both of these perspectives and still end up requiring the closure of the trapping season. So let’s start, today, with how you do ecological research. Later this week, I’ll get into the implications of the science that has been done, but for now, I’ll focus on the question of scale.

When you ask an ecological question, scale is one of the most important and immediate parameters to define. There are several types of scale to consider, and the most obvious is geographical scale. For example, if you’re interested in wolverines, are you interested in a single population node (a mountain range with at least one reproductive female), several interacting population nodes (say, the several occupied mountain ranges of southwestern Montana and northwestern Wyoming), or the entire metapopulation of the US Rockies, the Cascades, and maybe even the Sierra Nevada? You can ask the question “Is the population healthy?” at one geographical scale, and get a very different answer at that scale than you might at another scale.

In the world we live in, we also have to consider questions of jurisdiction, and whether or not we are spatially bounding our questions based on political borders. If we are, we have to ask whether imposing these artificial boundaries on our research limits the results – in other words, if we’re asking questions about twenty population nodes in a metapopulation that contains a hundred population nodes, are our answers applicable to the entire population? Or just to our study nodes? And if we ask only about the population nodes within our jurisdiction, are we confident that we understand the relationships among the study nodes and the nodes outside the study area?

Scale is also temporal, and temporal scale is directional, so your questions and your answers will be further bounded by whether you ask about trends that have occurred in the distant past or the recent past, and trends that you predict in the immediate future or the distant future. The question “Has the wolverine population in Montana been healthy enough to bear trapping in the past century?,” is substantially different from “Is the wolverine population healthy enough to bear trapping for the next two decades?” And that question, in turn, is different from the query, “Will trapping now have an effect on wolverine populations a century from now?”

These are management questions, not questions about simple knowledge (“What happened to the wolverines of Maryland, Virginia, Spain, and the Czech Republic at the end of the Pleistocene?” is an example of a question that is mostly about knowledge, with very few management implications) and at this point in the post, there’s an implicit subtext involving the influence of values on science and management, but we’ll get into that later. Right now, I’m going to assert that wolverines exist in a metapopulation that is interconnected throughout the Rockies, and that we must ask questions at that scale, and with a forward-looking temporal orientation, if we are going to figure out how to conserve the species.

MFWP has been asking questions about the population in Montana, based primarily on data and trends from the past, and without a clear articulation of how those trends might change in the face of climate change. The broader body of science conducted by other agencies and groups has been asking forward-looking questions, with data-collection frequently occurring at limited scales (Glacier National Park, the Greater Yellowstone region, the Payette National Forest) but always with a view to extracting broader trends in addition to information about specific populations. Papers like Copeland’s 2010 article on climate change and snowpack, Inman’s recent work on habitat modeling, and Schwartz’s papers on genetics all come out of large-scale questions.

Wolverines are in a unique situation: a once wide-ranging species was inadvertently extirpated and then began a process of recolonization that was monitored for decades by a state management agency at a small scale, and then other scientists began larger-scale studies that included some speculation about the future, and the results have entered the conservation debate at a moment when the trends of the past will be skewed by unprecedented climate disruption in the future. If we hope to protect the species, the science that we look to for management insight will have to be multi-scale, and it will have to integrate past trends with what we know about wolverines’ habitat requirements and our understanding of what will happen to that habitat in the future. There are, of course, serious political considerations at play in the discussion as well, but from a purely scientific standpoint, this is how these different studies operate and interact – not entirely at odds with each other, but at different scales, using different methodologies, and looking in different directions.

This is a pretty basic analysis. I have a series of doodles, constructed while watching the series Firefly during an epic descent into purely visual thinking (more about that later, too), which attempt to illustrate a model that encompasses both sets of science and that also tries to create a working picture of a wolverine metapopulation from 1900 through about 2100. Needless to say, it’s pretty rough, but if I can make it comprehensible, I might put a version up here. In the meantime, here’s another article, concise but nuanced, that also features a video of F5 in one of the live-traps in Glacier. This film highlights the endearing nature of the species. Enjoy.

Wolverines to be Listed as Threatened?

With apologies for the long silence, here’s an article in the Missoulian, more or less officially confirming news that we’ve been expecting – wolverines will be listed as threatened later this month. The news comes as part of a district’s judge’s decision not to hear a case, scheduled for January 10th, about the Montana trapping season: “District Judge Jeffrey Sherlock ruled it made little sense to debate a trapping season that was soon to become moot.” More details are available in an article from the Great Falls Tribune, which makes clear that the judge signed an order ending the 2012-2013 trapping season, even without the hearing, and that Montana Fish, Wildlife, and Parks decided not to fight the decision. In another piece in the Helena Independent Record, however, FWP indicated that they do plan to contest the lawsuit, should it go forward in March or April of this year. If wolverines are listed, though, today’s decision should represent the permanent closure of Montana’s trapping season – except in the unlikely event that we can slow down the effects of climate change enough to protect the population, or in the equally unlikely event that science somehow determines that trapping is not a threat despite the risks of climate change. This would be scientifically tricky to uphold, though, since removal of reproductive females from the population has the potential to significantly disrupt source nodes within the metapopulation, especially when habitat is decreasing.

More about this soon; I’m in the middle of several wolverine related projects (naturally) and haven’t had much time to write.  Meanwhile, here are a few other articles that have appeared over the past month:

NRCC Executive Director Jason Wilmot weighs in on the upcoming decision in a Greenwire article. This, too, basically stated that a “threatened” status was recommended; I plead guilty to being too absorbed in hanging out with my family over the holidays to post.

The Billing’s Gazette profiles the WCS wolverine study and the work of Bob Inman. The descriptions of the rigors of wolverine field work are pretty accurate, so if you’re contemplating a career in wolverine biology, ponder these carefully. He also raises an important but generally neglected question: the status and distribution of wolverines in Wyoming. This could be critical for a fully interconnected Rocky Mountain population, particularly if wolverines ever make it to Colorado. I hope that the state of Wyoming takes note, and prioritizes a study immediately. Bob also raises the issue of the inherently transboundary and transjurisdictional nature of wolverine conservation, which I hope will provide us with a new model for conservation of widely-dispersed metapopulations.

Much further afield, here’s an update on the tour of Michigan’s last known wolverine, tracked by teacher Jeff Ford for several years until her death in 2009.

Finally, here’s an interesting piece from Smithsonian, looking at adaptive plasticity in tree frogs in Panama. What does this have to do with wolverines in the Rockies? Adaptive plasticity is the range of behavior available to a species in light of environmental variation – including changes in climate. Since we cannot, as a society, muster the will to do anything about emissions, the continued presence of wolverines in the Rockies may well depend on the species’ degree of adaptive plasticity. This is one of the most important aspects of the comparative work in Mongolia and the US, too.

So there it is, for now. Enjoy the good news – but remember that putting a species on the list is not the equivalent of actually conserving it, and that the challenge for wolverines (and for other species) will be moving from symbolic protection to actual management strategies in the years to come.

note: I originally posted this as “Wolverines to be Listed as Threatened,” statement, not question. I was reiterating the headline of the first article that my friend sent me; I don’t have independent confirmation of this, and on reflection, I shouldn’t have stated this as a fact. Although the decision is due out sometime soon, and although we have indications that they will be recommended for protections, I do not actually know that they will. Hopefully this hasn’t caused any confusion or bad feeling, and hopefully readers will forgive the lapse in the usually-rigorous standards on this blog.