Tag Archives: ecosystem

Free homeschool guide to Arctic sea ice ecology

I have put together a Arctic Sea Ice Ecosystem Teaching Guide for homeschooling Arctic sea ice ecology at the middle school level (grade 5-8; ages 10-13) meant to complement my two books, Polar Bear Facts & Myths and Walrus Facts & Myths and supplement your local school board curriculum. You’ll find critical facts about the amazing creatures that inhabit the Arctic sea ice, links to trust-worthy online sites with additional information, suggested exercises, and links to fascinating videos like this one that aren’t filled with doom-mongering about the future. The printable pdf booklet is free to download here (single typo in original corrected). However, if you find it useful and can afford to do so, please consider a small donation (I suggest $6.00) at the ‘donate’ button to the right.

New report: Change coming to the Canadian Arctic — but it’s no looming catastrophe

A review of a newly-released (22 April 2020, on Earth Day) report commissioned by Canada’s Department of Fisheries and Oceans on the state of the Arctic seas published today in the National Post is a must read. It highlights the report’s emphasis that while the changes going on in our northern seas are indeed marked, they do not necessarily spell doom.

2019 DFO Arctic Report_Polar Bears from Summary document sent to media

Oddly, polar bears are primarily represented in the report by an overview account of the special case of Western Hudson Bay – an outlier among Canadian subpopulations – that puts special emphasis on the claimed decline in body condition blamed on recent sea ice changes that is not supported by any recent data (Crockford 2020).

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Arctic sea ice habitat for polar bears is like a big pond that dries up partially in summer

What’s a good analogy for sea ice as essential polar bear habitat? Biologist Andrew Derocher claims that the soil in a forest is appropriate, because without the soil you can’t have the forest ecosystem. However, that’s a specious comparison because the amount of soil in a forest does not change markedly with the seasons the way that Arctic sea ice does.

polar-bear-arctic-ice_21-aug-2009_patrick-kelley-us-coast-guard.jpg

A much better analogy is a big pond that dries up a bit every summer. The amount of habitat available to sustain aquatic plants, amphibians and insects is reduced in the dry season but many species have special adaptations for surviving reduced water availability. For the rest of the year, however, the pond provides an abundant and non-limiting habitat for all the creatures and plants that live there.

Beaver pond USFWS

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Spring feeding for polar bears is over – sea ice levels are now largely irrelevant

Polar bears in virtually all regions will now have finished their intensive spring feeding, which means sea ice levels are no longer an issue. A few additional seals won’t make much difference to a bear’s condition at this point, except perhaps for young bears that haven’t had a chance to feed as heavily as necessary over the spring due to inexperience or competition.

Polar bear feeding by season simple_Nov 29 2015

The only seals available on the ice for polar bears to hunt in early July through October are predator-savvy adults and subadults. But since the condition of the sea ice makes escape so much easier for the seals to escape, most bears that continue to hunt are unsuccessful – and that’s been true since the 1970s. So much for the public hand-wringing over the loss of summer sea ice on behalf of polar bear survival!

Polar bears in most areas of the Arctic are at their fattest by late June. They are well prepared to go without food for a few months if necessary – a summer fast is normal for polar bears, even for those that spend their time on the sea ice.

Putting on hundreds of pounds of fat in the spring to last through periods of food scarcity later in the year (at the height of summer and over the winter) is the evolutionary adaptation that has allowed polar bears to live successfully in the Arctic.
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