Changing snowpack a concern for caribou: scientist

Changing snowpack a concern for caribou: scientist
A group of Bathurst caribou travels just south of Wekweeti. Scientists believe the herd’s decline could be due in part to changes to the snowpack caused by climate change that make it difficult for the animals to access their primary food source, lichen.Photo: Dr. Michael English.

As political discussions on how to address the declining numbers of the Bathurst caribou herd continue in the NWT, one scientist says changes in the snowpack could be a contributing factor to the growing crisis.

Dr. Michael English, who co-directs Wilfrid Laurier University’s Cold Regions Research Centre and acts as chair of its Geography and Environmental studies department, took time away from his annual research to share his findings with the public on Feb. 5.

“The objective of the work we’re doing is to try and understand if changes in the snowpack are perhaps a factor in the decline of the Bathurst caribou herd,” English said in an interview with The Journal. “This might apply to other herds as well because about 65-70 per cent of all the caribou herds in the Northern hemisphere are declining significantly.”

The Bathurst herd has shrunk by almost 90 per cent in the last decade or so, over which time hunters on the land say they have noticed an increase in ice crust, said English, who has spent the past three years focusing his studies on the region around Wekweeti.

For six to seven months of the year, caribou have to dig through the thick layers of snow cover to get to buried lichen and other food sources – an impossible task when ice “lenses” or thick crusts build up due to increased solar radiation emissions and temperature fluctuations.

While roaming around in search of their next meal, caribou often become bloodied and bruised on their forelegs as they step through the jagged ice that scratches at their skin, hindering their ability to run. This also increases the caribou’s chance of being taken down by wolves, which have the advantage of being light enough to run on top of the snow to hunt down their weakened prey.

As an indicator of changing climate conditions, snow can also provide insight as to how severe fires will be over the summer. Below-average snowfall measurements usually mean higher chances of wildfire and burnt old-growth lichen – caribou’s primary food source – which can take 50 to 60 years to recover.

English and his team are employing a combination of strategies to research the snowpack factors, all of which he is hoping to teach Wekweeti residents in order to create a community monitoring program.

Those include using satellite images of naturally-occurring radiation in the form of micro-wavelengths emitting from the snow, which can help indicate where the thicker layers of snowpacks are located. Samples from the snow and surrounding water bodies are also collected in order to measure the snow’s water equivalency, or the density of water in the snow. These measures, in conjunction with Environment and Natural Resources (ENR) records tracking the movements of collared caribou, help the scientists understand whether herds are avoiding these hard-snowpack areas, though sometimes, English acknowledged, they just can’t be avoided.

“It certainly looks like the North is warming now and it’s probably going to continue to warm, which means that the length of time the snowpack is on the ground is probably going to be reduced as the growing season increases,” English said. “The period of time where the snowpack can be affected by changes in temperature is probably going to be increased too.”

This could mean short, harsh winters for the herd in the future.

Hopefully, English said, his research will help inform policy on the preservation of the caribou, such as this year’s harvest ban for the Bathurst.

“I don’t know what else they could do at this point,” English said. “It’s a tough situation.”

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