Tag Archives: species

USA finally updates Endangered Species Act after 45 years & the decision is final

Just out this morning:

Today, U.S. Secretary of the Interior David Bernhardt unveiled improvements to the implementing regulations of the ESA designed to increase transparency and effectiveness and bring the administration of the Act into the 21st century.” USFWS Press Release, 12 August 2019.

Although much hue-and-cry will be written by conservation organizations and the media (here is one), I am providing for easy reference here links to the original press releases and documents issued this morning by the Department of the Interior and the US Fish and Wildlife Service. I am also providing pdf copies of the official documents to appear shortly in the Federal Register and quote the above USFWS press release in full.

Polar_bear_resting_but_alert_original USFWS

It remains to be seen whether polar bears or other Arctic species of interest to me and readers of this blog will be affected. The new changes affect both the listing and delisting process as well as designation of critical habitat.

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New genetics paper is not about whether climate change causes polar bear hybrids

A new paper on the evolutionary history of bears (Bears breed across species borders: Kumar et al. 2017) has concluded that hybridization is common and natural among all species of ursids. And while some media outlets (e.g. DailyMail) have framed this as surprisingly convincing proof that experts were wrong to claim that climate change is the cause of recent polar bear X grizzly hybrids, definitive evidence against that interpretation has been available for years to anyone who bothered to look: see my recent “Five facts that challenge hybridization nonsense.”

This genetic evidence is just a cherry on top of the rest but will help get the paper the media attention the authors crave.

Polar bear X grizzly hybrids were known long before climate change and sea ice decline became an issue. See also previous posts here, here, and here. In fact, as I’ve pointed out, “most polar bear hybrids said to exist have not been confirmed by DNA testing” (including virtually all of the bears specialist Andrew Derocher claimed were hybrids, including the latest one from 2016 that prompted such gems as “Love in the time of climate change”).

pizzly_andrewderocher_300dpi_2017 paper

A polar bear X grizzly hybrid, see Kumar et al. 2017. Photo by A. Derocher.

In my opinion, the most important conclusion of this paper is that occasional but widespread hybridization among bears is why it has been so hard to say with confidence when polar bears arose (which I addressed years ago, in my Polar bear evolution series: Part 1, Part 2, and Part 3). You cannot use traditional methods of pinpointing the timing of speciation events from genetic data if one or more of the species have hybridized (traded genes). See the long, fuzzy “divergence times” for bears in the image below from the Kumar paper.

Kumar et al 2017 hybridization in bear evolution_fig 5

From Kumar et al. 2017, Fig. 5: “The scale bar shows divergence times in million years and 95% confidence intervals for divergence times [speciation events] are shown as shadings.”

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