Wildfires threaten polar bear

2012-08-17 09:35
Wildfires sparked by lightning near Canada's Hudson Bay are threatening the habitat of polar bears. (AP)

Wildfires sparked by lightning near Canada's Hudson Bay are threatening the habitat of polar bears. (AP)

Multimedia   ·   User Galleries   ·   News in Pictures Send us your pictures  ·  Send us your stories

Washington - Wildfires sparked by lightning near Canada's Hudson Bay are threatening the habitat of polar bears, encroaching on the old tree roots and frozen soil where females make their dens, a conservation expert on the bears said.

Polar bears are more typically threatened by the melting of sea ice, which they use as platforms for hunting seals, their main prey. But those who live near Hudson Bay spend their summers resting up on shore when the bay thaws, living in dens dug in the frozen soil among the roots of stunted spruce trees.

Fires in this area are rare, said Steven Amstrup, a former polar bear specialist with the US Geological Survey and now chief scientist at the non-profit conservation organisation, Polar Bears International.

"It's a cool, wet environment that doesn't burn very often," Amstrup said by telephone from Washington state. "It's not an environment where the forest is adapted to fires very much."

Unusually hot, dry weather in Manitoba, Canada, and lightning strikes caused several fires through Wapusk National Park across known polar bear dens in July, said Manitoba Conservation Officer Daryll Hedman.

Dens

High temperatures this week in Churchill, Manitoba, were in 15°C to 18°C, with overnight lows above freezing. The US National Snow and Ice Data Centre indicated in a map of Arctic ice cover released this week that the vast majority of Hudson Bay is ice-free.

Female polar bears in the western Hudson Bay population use dens under the root crowns of small, slow-growing spruce trees that grow in permafrost soils along the banks of rivers and lakes. Some dens have been used for over 100 years.

"Not only is the permafrost no longer permanent, tree roots needed to stabilise the den structure are disappearing," Amstrup said. "The kinds of habitats where mother polar bears in this area give birth to their cubs are simply disappearing as the world warms."

Historically, the soil in most areas around Hudson Bay is frozen solid below a surface layer about 30cm thick that thaws and re-freezes seasonally, Amstrup said.

In recent years, that top layer of soil has become increasingly thicker, so the thawing goes deep enough to defrost the soil around the tree roots, making the openings that the bears dig collapse, Amstrup said.

When the trees burn, as some may this summer, their roots die out and further damage the polar bear dens, he said.

Unlike other polar bear populations, where pregnant females use dens dug in snow, Hudson Bay females come ashore to these tree-root dens to rest and give birth, remaining in the dens until the following spring.

Government protection

"They're essentially food-deprived in the summertime. They come ashore and basically just rest and try to save energy. They crawl into these dens, it's cool in there, they're not harassed by insects and they basically just rest until the snow comes and until they give birth," Amstrup said.

Without these earthen dens, he said, females would not be able to conserve their energy as well. And if snow does not come early enough, cubs could be born out in the open, where they would be exceedingly vulnerable.

"Cubs are born at about a pound and a half [680g], blind, nearly hairless, essentially immobile and totally helpless," he said. "Their survival depends upon the shelter of the den to protect them from the elements."

Polar bears have government protection in Canada and the US. The US polar bear population in Alaska is listed as threatened under the Endangered Species Act because of increasing damage to their icy habitat by climate change.
Read more on:    animals
NEXT ON NEWS24X
SHARE:

Read News24’s Comments Policy

24.com publishes all comments posted on articles provided that they adhere to our Comments Policy. Should you wish to report a comment for editorial review, please do so by clicking the 'Report Comment' button to the right of each comment.

Comment on this story
0 comments
Add your comment
Comment 0 characters remaining
 

Inside News24

 
/News
 

Joburg hot spots for cocktails, craft beer, tapas and wine!

It’s the season to be jolly – so we’ve rounded up some new Joburg hot spots!

 
 

I love summer.24

Christmas lingerie to make this festive season the best one ever!
13 things you might not know about Disneyland
The craziest deaths of 2014
How to make this a sensual, sexy summer!

Jobs in Cape Town [change area]

Property [change area]

Travel - Look, Book, Go!

Kalahari.com - shop online today

2DAYS ONLY – 30% off Appliances

Coffee makers, blenders, fans, juicers and more. T&Cs apply. Shop now!

2 DAYS ONLY – 40% off books

Get 40% off when you buy 2 books. For two days only! T&Cs apply. Buy now!

Up to 50% off on outdoor gear

Save on chairs, blankets, cooler bags, umbrellas and more. Shop now!

Save on Samsung

Cameras, mobile phones, TVs, Tablets and more. While stocks last. Shop now!

Grand Theft Auto 5

Now available on PS4, Xbox One and PC from R649. Buy now!

OLX Free Classifieds [change area]

Samsung Galaxy s4

Mobile, Cell Phones in South Africa, Western Cape, Cape Town. Date October 24

Best bargain in big bay

Real Estate, Houses - Apartments for Sale in South Africa, Western Cape, Cape Town. Date October 25

VW Golf 6, 1.6 Trendline (Excellent condition)

Vehicles, Cars in South Africa, Western Cape, Cape Town. Date October 25

Horoscopes
Aquarius
Aquarius

At last you are able to see the light. You are able to break through obstacles in an innovative and original way. Visualisation is...read more

There are new stories on the homepage. Click here to see them.
 
English
Afrikaans
isiZulu

Hello 

Create Profile

Creating your profile will enable you to submit photos and stories to get published on News24.


Please provide a username for your profile page:

This username must be unique, cannot be edited and will be used in the URL to your profile page across the entire 24.com network.

Settings

Location Settings

News24 allows you to edit the display of certain components based on a location. If you wish to personalise the page based on your preferences, please select a location for each component and click "Submit" in order for the changes to take affect.








Facebook Sign-In

Hi News addict,

Join the News24 Community to be involved in breaking the news.

Log in with Facebook to comment and personalise news, weather and listings.