Category Archives: Population

W Hudson Bay mark-recapture studies of polar bears were invalid, says peer-reviewed study

“Our results suggest that mark–recapture estimates may have been negatively biased due to limited spatial sampling. We observed large numbers of bears summering in southeastern WH, an area not regularly sampled by mark–recapture.” Stapleton et al. 2014.

Polar bear at Wapusk National Park (just south of Churchill) in August 2011. Courtesy Parks Canada.

Polar bear at Wapusk National Park in August 2011. Courtesy Parks Canada.

We’ve seen the results of this 2011 study before, in government report format. But now it’s been revamped, peer-reviewed and published in a respected scientific journal – it actually came out in February, without fanfare, but I’ve only just come across it.

Some excerpts below, with conclusions that should raise some eyebrows.

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Counting bears from space can be just as accurate as by helicopter, claims new study

Satellites images might be able to replace aerial counts of polar bears in some places — if there are no clouds. But it seldom distinguishes cubs and can’t tell males from females, found a 2012 study of Foxe Basin bears that’s just been published.

Foxe Basin polar_bears_rowley_island_Stapleton 2012 press photo labeled sm

Note: This is my 200th post since July 26, 2012!

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Are Polar Bears Really Endangered?

Christina Wu at the Urban Times (July 3, 2014) recently asked this question. She came up with a surprisingly balanced argument but some predictable responses from IUCN Polar Bear Specialist Group (PBSG) biologists. As a consequence, she overlooked some critical facts that make a big difference to the answer.

Figure 1. Are polar bears really endangered? The US Fish and Wildlife Service thinks so, but only because Steven Amstrup, based on a computer model projecting sea ice out to 2050, said so (Amstrup et al. 2007). This information has been used by the Center for Biological Diversity and other NGOs, like WWF and Polar Bears International (where Amstrup is now employed), to solicit donations.

Figure 1. Predictions of polar bear population declines by 2050 are being used by the Center for Biological Diversity, WWF and Polar Bears International to solicit donations.

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Polar Bear Specialist Group just had another secret meeting

Well, well, well — it looks the Polar Bear Specialist Group (PBSG) just had itself another secret meeting with some extra special guests.

pbsg logoPolar bear scientists and PBSG-approved activists got together a few weeks ago (June 9-13), with no notice beforehand, to continue discussions how (sic) to solve issues of future capacity.”

This was their “second intersessional members-only meeting in a row” (the first one was in October 2012), but they still haven’t had their regular, now long-overdue, “working meeting.” [they had the last one in 2009].

I came upon a notice about this meeting on the PBSG website, which apparently went up June 26, while looking for something else. There has been nothing about it in the media that I’ve seen.

And guess who were “invited specialists” at this meeting of “members-only,” called “to discuss internal matters crucial for the future functioning and capacity of the group”?

Three “climate scientists“!

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IUCN Polar Bear Specialist Group says its global population estimate was “a qualified guess”

Last week (May 22), I received an unsolicited email from Dr. Dag Vongraven, the current chairman of the IUCN Polar Bear Specialist Group (PBSG).

pbsg logo

The email from Vongraven began this way:

Dr. Crockford

Below you’ll find a footnote that will accompany a total polar bear population size range in the circumpolar polar bear action plan that we are currently drafting together with the Parties to the 1973 Agreement. This might keep you blogging for a day or two.” [my bold]

It appears the PBSG have come to the realization that public outrage (or just confusion) is brewing over their global population estimates and some damage control is perhaps called for. Their solution — bury a statement of clarification within their next official missive (which I have commented upon here).

Instead of issuing a press release to clarify matters to the public immediately, Vongraven decided he would let me take care of informing the public that this global estimate may not be what it seems.

OK, I’ll oblige (I am traveling in Russia on business and finding it very hard to do even short posts – more on that later). The footnote Vongraven sent is below, with some comments from me. You can decide for yourself if the PBSG have been straight-forward about the nature of their global population estimates and transparent about the purpose for issuing it.
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Earth to Newsweek: polar bear populations have not been on the decline since 2008

A recent Newsweek story about the US Navy having no “rules of engagement” to deal with polar bear encounters leads with alarmist misinformation.

Photo credit Cmdr. Christy Hagen/U.S. Navy

Photo credit Cmdr. Christy Hagen/U.S. Navy

Author Max Strasser (April 30, 2013), in his recent article in Newsweek (As the World Warms, Navy Strategists Plan for an Arctic Rush”) [h/t D. V]

Approximately 25,000 polar bears live in and around the Arctic Circle. Climate change has put the majestic ursines, a longtime favorite of children’s books and Christmas cards, in peril. In 2008, the United States listed them as a “threatened species” under the Endangered Species Act, and populations have been on the decline since then.”

Sigh. Not so Max, totally not so.

Global polar bear numbers have been stable for the last 30 years, as the graphs below show. The proposed ‘threat’ to polar bears is a future decline in sea ice predicted by computer models. The future, Max, is not now.

Polar bear populations are currently doing very well (see my post on the most recent status update report here). On top of that, note that the bears are well distributed throughout available Arctic habitat — one of the accepted hallmarks of a healthy species.

Figure 1. Upper graph uses totals reported in PBSG status tables, with min/max; Lower graph uses the same figures, but adds back in the so-called "inaccurate" estimates dropped 2005-2013. The 1960 figure * is a ballpark estimate. See previous post here.

Figure 1. Upper graph uses totals reported in PBSG status tables, with min/max; Lower graph uses the same figures, but adds back in the so-called “inaccurate” estimates dropped 2005-2013. The 1960 figure * is a ballpark estimate.
See previous post here.

OK, with that error corrected, back to the point of the Newsweek story…

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Southern Beaufort polar bear ‘decline’ & reduced cub survival touted in 2008 was invalid, PBSG now admits

It is now clear that the phenomenon of bears moving across Southern Beaufort Seapbsg logo subpopulation boundaries compromised the US decision to list polar bears as ‘threatened’ and the IUCN Polar Bear Specialist Group (PBSG) knows that was the case.

As I pointed out last week, the PBSG has admitted in their 2013 status table update (pdf here) that bears move around so much between the Chukchi Sea (CS), the Southern Beaufort (SB), and the Northern Beaufort (NB) subpopulations that major changes in the boundaries of the SB subpopulation are necessary (see Fig. 1 below).

Figure 1. From the paper by Amstrup and colleagues (2005) describing the effect that movement of bears across subpopulation boundaries has on setting harvest quotas – and population estimates. Southern Beaufort boundary is solid red, Chukchi Sea is dashed yellow and Northern Beaufort is dotted light blue. “Point Barrow” is Barrow, AK (well inside the SB boundary). Click to enlarge.

Figure 1. From the paper by Amstrup and colleagues (2005) describing the effect that movement of bears across subpopulation boundaries has on setting harvest quotas and population estimates. Southern Beaufort (SB) boundary is solid red, Chukchi Sea (CS) is dashed yellow and Northern Beaufort (NB) is dotted light blue. “Point Barrow” is Barrow, AK (well inside the SB boundary). Click to enlarge.

Well, that’s not really news — changes to the SB boundaries were promised by the PBSG back in 2009 (Obbard et al. 2010), based on research by Steven Amstrup and colleagues published in 2001 and 2005. But now, in an astonishing admission, the PBSG have acknowledged that the last population survey for the SB (Regehr, Amstrup and Stirling, 2006), which appeared to register a decline in population size and reduced cub survival over time, did not take known movements of bears into account as it should have done.

In other words, that 2006 study almost certainly did not indicate bears dying due to reduced summer sea ice in the SB, as biologists said at the time — and which they presented as evidence that polar bears should be listed by the ESA as ‘threatened’ — but reflected capture of bears that were never part of the SB subpopulation and so moved out of the region.

As the PBSG said about the 2006 estimate:

“…it is important to note that there is the potential for un-modeled spatial heterogeneity in mark-recapture sampling that could bias survival and abundance estimates.” [my emphasis]

Spatial heterogeneity” means that the sampled bears could have come from more than one population, a possibility which violates a critical requirement of the statistics used to generate the population and survival estimates. “Un-modeled” means that the ‘movement of bears’ problem was not factored into the mathematical models that generated the 2006 population size and survival estimates as it should have been.

Ecologist Jim Steele pointed some of this out in his book and his guest post last year, so it’s not news that this was done.

What’s shocking is that the PBSG have now admitted that the ‘movement of bears’ issue essentially invalidates the 2006 population estimate and the much-touted ‘reduced survival of cubs.’ The reduced survival of cubs data from that SB study was a critical component of the argument that US bears were already being negatively impacted by global warming and thus, should be listed as ‘threatened’ under the ESA (US Fish & Wildlife Service 2008).

Since the population decline and reduced survival is now acknowledged to be unfounded — and perhaps deliberately so — I ask you this: will a new SB survey — soon to be released by the same lead author (Eric Regehr) — undo the broken trust in US and PBSG polar bear biologists? Continue reading

Polar bear status changes in 2013 deconstructed, with a map to the good news

You can’t figure out what’s going on with status updates from the IUCN Polar Bear Specialist Group (PBSG) without deconstructing the spin and the 2013 update is no exception. Here’s my travel guide, with a map, to the good news.

Polar Bear Subpopulations 19_2013 updates_March 20 2014_sm

I’ve finally had a chance to go through all of the details provided with the 2013 PBSG status table (pdf here). It’s just about all good news, once you wade through the spin. Numbers aside, out of the 13 populations for which some kind of data exist, five populations are now classified by the PBSG as ‘stable’ (two more than 2009), one is still increasing, and three have been upgraded from ‘declining’ to ‘data deficient’ (I explain below why this is a promotion).

That leaves four that are still considered ‘declining’- two of those judgments are based primarily on concerns of overhunting, and one is based on a statistically insignificant decline that may not be valid and is being re-assessed (and really should have been upgraded to ‘data deficient’). That leaves only one population – Western Hudson Bay – where PBSG biologists tenaciously blame global warming for all changes to polar bear biology, and even then, the data supporting that conclusion is still not available.

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Guest Post: Invasive Research is Alive and Well in Canada

This is a guest post by Kelsey Eliasson, who blogs at Polarbearalley, with his thoughts on the issue of the invasive research involved in polar bear mark-recapture studies around Churchill, Manitoba — which, as you’ll see, is a far different situation than I described for Nunavut (previous posts here, here, and here on this topic. Map below to get you oriented).

Kelsey is a writer, artist and polar bear guide who has spent 14 bear seasons watching the polar bears of Churchill. For five years, he ran Churchill’s monthly newspaper published occasionally, the Hudson Bay Post. Currently, he divides his year between the Yukon, Churchill and, occasionally, Riverton, home of Manitoba’s largest moose statue.

Churchill is in the Western Hudson Bay polar bear subpopulation, governed by the Province of Manitoba, while the community of Arviat, also in 'Western Hudson Bay' is overseen by the Government of Nunavut.

Churchill lies in the Western Hudson Bay (WHB) polar bear subpopulation, governed by the Province of Manitoba, while the community of Arviat, also in the Western Hudson Bay subpopulation, is overseen by the Government of Nunavut – different governments, different rules – as Kelsey points out below.

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Invasive Research is Alive and Well in Canada, by Kelsey Eliasson

The recent post about Foxe Basin was of particular interest to me, as I have been following the growing gap between the north and science for some time now. The stance taken by the Inuit is viewed as an inspiration by the guides over here in Churchill. For many years, we have tried to voice our deep concerns over the levels of handling and drugging that our bears (the Western Hudson Bay population) are subjected to on an annual basis.

This time last year, I tried to raise the topic for discussion after Andrew Derocher announced that ‘everything was on the table’ including feeding bears. At that time, the top polar bear researchers had sat down to discuss options for saving bears – except reducing handling and research – i.e. chasing bears down by helicopter and then shooting them with tranquilizers. Continue reading

Foxe Basin aerial survey a watershed moment for polar bear research, Part 2

As I outlined earlier this week, Canadian Inuit objected so strenuously to routine mark-recapture methods used by polar bear biologists during the early days of a Foxe Basin population study in 2008 that the work was abandoned and an aerial survey done instead.

In this post, I’ll examine how the polar bear biologists involved reacted to that crisis, which they called a “control of research” issue.

In a published version of a conference paper, co-authored by two of the original investigators of the Foxe Basin mark-recapture study, Lily Peacock and Andrew Derocher (Peacock et al. 2011:374), had this to say:

Control of research is a developing source of conflict. In recent years, some permits for management-oriented research on polar bears were denied by the Government of Nunavut, local hunting and trapping organizations in the Northwest Territories, and by Makivik Corporation in Quebec. Furthermore, in a 2009 resolution, Inuit Tapiriit Kanatami opposed the capture of polar bears throughout Canada (available by request from http://www.itk.ca), even though the application of physical marks is one of the most effective methods of population estimation. Co-management is particularly difficult in Nunavut because of the large number of subpopulations (12), which makes it difficult to fund and conduct research.” [my bold]

They raised an interesting point – since the Government of Nunavut has the power to insist biologists do more than reiterate that their way of counting bears is the only acceptable way, and because the government can deny permits to projects that don’t measure up, it can lock out traditional polar bear research for virtually all of Canada (the vast majority of Canada’s 13 subpopulations are in Nunavut, see Fig. 1), especially since aboriginal organizations in the Northwest Territories and Quebec have followed Nunavut’s lead.

Figure 1. Territory covered by the Government of Nunavut (top, Wikipedia) and the 13 polar bear subpopulations in Canada (bottom, Environment Canada).

Figure 1. Territory covered by the Government of Nunavut (top, Wikipedia) and the 13 polar bear subpopulations in Canada (bottom, Environment Canada).

That means if polar bear researchers can’t find a way to make their research mesh with Inuit concerns, they’ll be out of work in Canada. Let’s take a look at their approach and see how well it worked for them — explaining in part the new prominence of aerial surveys for population assessments. Continue reading