Wildlife

Wildlife Wednesday: Arctic fox “green thumb” effect on tundra can be seen from space

Plus: record-breaking polar bears in Churchill, problem-solving racoons in Vancouver, and the urban song sparrows-turned super dads.

Arctic foxes play a vital "eco-engineer" role in tundra landscape. (Photo: Rawpixel [CC0])
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Arctic foxes are ecosystem engineers that have a green thumb effect on the tundra ​​— and their influence can be seen from space.

According to biologists at the University of Manitoba, Arctic foxes benefit plants in the Arctic tundra ecosystem due to their denning activity. The researchers ascertained this by spying on Arctic foxes around Churchill, Man., (the southern range of Arctic fox habitat, where they occasionally choose to den) using high-resolution satellites. These areas are nutrient poor and without much vegetation — until the foxes move in. Their dens become a nutrient sink in an otherwise barren landscape as the foxes drag in their kills, often snow geese or lemmings, leaving behind piles of bones, feathers and leftover flesh. Lush grasses and other vegetation sprout up around the den over time, boosted by fertilization from fox urination and defecation.

The effect is seen in the satellite images; the dens are visible as oases of green shrubbery dotting the stark landscape. They stay long after the foxes leave, suggesting a long-term ecological boost, attracting regular visits from other Arctic mammals such as polar bears, caribou and wolves. 

But, just as their importance becomes apparent, so does their declining population. Climate change appears to be driving Arctic fox numbers down in northern Manitoba, threatening the biodiversity they support so well. As temperatures rise, the layers of snow supporting their prey of choice, lemmings, are no longer forming. The Arctic fox population in northern Manitoba is now about half the size it was in the1950s. 

“The implication of [the declining numbers] is that there won’t be Arctic foxes in Manitoba one day,” University of Mantioba biologist Sean Johnson-Bice told CBC.

Record breakers

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Churchill, Man., is on course for a record number of polar bear reports this season, say local conservation officers.

The Hudson Bay town is no stranger to polar bears, having earned the nickname “polar bear capital of the world” due to its position at the heart of a natural polar bear corridor. The title couldn’t be more true this year, with 76 calls about polar bears in and around Churchill as of Aug. 16, compared with 18 by  the same date last year. Officers have also been forced to capture, sedate and move three of the bears into the town’s polar bear holding facility, an action not usually required until October.

“There are so many polar bears in and around the town of Churchill we are looking at record numbers this year and that’s heavily influenced by where the last ice in the Hudson Bay melts,” said Churchill conservation officer Chantal Maclean, speaking to CBC.

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No problem!

Raccoons are notorious for their destructive behaviours, but UBC researchers are hoping to find out how we can better co-exist with these urban scavengers. (Photo: Brenda Doherty/Can Geo Photo Club)
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Love them or hate them, “trash pandas” are wreaking havoc across Canada, cooling off in pools, picking through garbage bins, and even wandering through local grocery stores. But in an effort to learn how we can better minimize conflict with these urban scavengers, scientists at UBC are looking to test raccoons’ IQ so we can understand how we can better co-exist.

Researchers say that raccoons are known to be adaptable to their surroundings, but how adaptable are they really? UBC’s Urban Wildlife Project is using humane traps to capture raccoons, microchip them, provide food and water and then set up a series of puzzles for this inquisitive species to solve. These puzzles will test raccoons’ cognitive abilities, such as memory, learning, self-control and behaviour. 

Hannah Griebling, a UBC Ph.D. student, says that if they do well at one task, they are going to do well in another and that they have to use multiple cognitive domains in order to do different tasks. 

To fully study raccoons properly, the research group needs about two dozen Vancouver-based volunteers to lend their backyards to the research being conducted. Motion-activated infrared cameras will be set up to capture the raccoon’s problem-solving skills while also monitoring their performance as they interact with these different cognitive tasks. The research group is also looking for a few hundred volunteers to participate in an online survey about observed raccoon behaviour.  

Researchers say it will be a good idea to get a better understanding of their behaviours, even the ones we may not necessarily like. 

To volunteer your backyard for the study, email [email protected] 

Urban Legends

Urban song sparrows make the best dads. (Photo: Rhododendrites, via Wikimedia Commons [CC BY-SA 4.0])
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Obnoxious, aggressive and…. awesome daddies? 

A recent study published in Frontiers in Ecology and Evolution has discovered that urban-dwelling songbirds are more attentive fathers than their country counterparts.

With fewer nesting sites available in cities, researchers expected — and found — that city-dwelling song sparrows were more aggressive in defending their territory than their rural counterparts. 

But with urban male songbirds spending more time securing their space, researchers thought they’d likely have less time to care for their young, which, in turn was expected to have a negative impact on their survival.

Wrong! Turns out these urban super-dads also made more visits to the nest and started feeding their young earlier in the day, with the result that urban nests actually had a higher survival rate than those in rural sites.

In an interview with phys.org, the lead publication author Samuel Lane summed up the findings: “It is often assumed that urban areas are more challenging for wild animals,” he noted. “Our study adds to growing evidence that certain species of songbirds even benefit from living in urban environments when there is sufficient green space for them to find food and nest locations.” 

The scientists hope ongoing research in this field will contribute to designing urban environments that support wildlife better.

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