Legless in the Yukon

Over the last few years, while conducting field work in the northern Yukon, Bruce Bennett has turned up some unexpected bits of wildlife -- a few small worms wriggling through the damp, shallow soil of the tundra.

By Claire Eamer

Over the last few years, while conducting field work in the northern Yukon, Bruce Bennett has turned up some unexpected bits of wildlife—a few small worms wriggling through the damp, shallow soil of the tundra.

Bennett, a Yukon government biologist, was surprised to find “earthworms” so far north.

However, worm expert Valin Marshal of Victoria says at least one of the tiny worms isn’t an earthworm at all. It belongs to a related group, the enchytraeids, which are also called iceworms or potworms.

Another of Bennett’s finds, from the Peel River valley, is indeed an earthworm, or lumbricid. Ontario expert John Reynolds recently confirmed the identification based on Bennett’s photograph of the little animal.

The photo wasn’t enough to determine the worm’s species, but it’s still an extremely rare find. Most worms found in the Arctic are potworms, not earthworms, Marshal says.

It’s not easy to tell the difference between earthworms and potworms. Potworms are generally smaller than earthworms, but some large potworms could easily be mistaken for earthworms, says Marshal. Potworms like wet habitats, but so do some earthworms.

The most obvious external difference is that earthworms have pigment that gives their bodies some kind of colouring. Enchytraeids are translucent. The other differences are generally too small to see without magnification, or they’re internal.

“There are not too many people in Canada who can tell these things apart,” says Marshal.

Both lumbricids and enchytraeids live in the Yukon, but we have only a broad idea of which worms are present, where they live, and where they came from.

We do know that a lot of the earthworms are fairly recent immigrants. A limited worm survey by Syracuse University graduate student Chelsea Teale a couple of years ago turned up four earthworm species in gardens and parks in Whitehorse. Two of them arrived in composting material discarded by Whitehorse in 2004.

Others have been introduced by residents doing their own composting or trying to improve their garden soil. Sometimes worms arrive along with soil or plants imported from other locations.

“At least seven earthworm species are known from the Yukon,” says Marshal. “Most of these earthworms were likely spread through human activity during the last century.”

However, a couple of species could have survived in the Arctic right through the last glacial period. Both Bimastos parvus and Eisenia nordenskioldi have been found in Russia, in terrain and climate much like the Yukon’s. The little worm from the Peel River might be one of these two species.

Bimastos parvus has been spotted in the Yukon before, on the east shore of Kluane Lake and in the Sheep Mountain area. Marshal says Eisenia nordenskioldi could be in the Yukon too. It’s widespread in northeastern Siberia and Wrangel Island, just across the Bering Strait from Alaska and the Yukon.

“Many of these earthworm species are very widely distributed, if you look in the right place.”

Potworms, on the other hand, are fairly common in arctic regions. They like wet conditions, Marshal says, so you find them on seashores, in sewage sludge, and even in habitat that is more water than land.

They are more tolerant of cold than earthworms, and they have a reproduction strategy that suits northern conditions. Both earthworms and potworms deposit both sperm and eggs in cocoons. Baby worms develop and grow in the cocoons.

However, the cocoons can stay dormant for a long time, even through an arctic winter, until conditions are suitable for young worms to hatch out. Enchytraeids increase their reproduction odds even more by producing lots of cocoons in a season.

“These animals are pretty resourceful,” says Marshal.

We have a lot to learn about worms, but few people are studying them in Canada. Marshal, one of a handful of experts in Western Canada, retired recently, and he says not many people are entering the field.

“It’s not a very well-paying profession currently.”

Worm experts are needed if we’re to understand ecological processes and how they are changing, but it’s hard to attract students and funding.

And it’s hard to find the worms, especially in places like the Yukon, where pockets of worm habitat are scattered across a huge area.

“You need experts to scour the place and know where to look and how to identify them. Then you have to collect the worms properly in order to work with them.”

Both the taxonomy and ecology of worms are wide open fields for future biology students, he says.

For more information about earthworms in Canada, go to the website of the Worm Watch Program at www.frogwatch.ca/english/wormwatch.

This column is co-ordinated by the Northern Research Institute at Yukon College with financial support from Environment Yukon and Yukon College. The articles are archived

at www.taiga.net/yourYukon.

Get local stories you won't find anywhere else right to your inbox.
Sign up here

Just Posted

Yukon RCMP say they’ve received three reports of youth being extorted online. (Black Press file)
Yukon youth being extorted online

Yukon RCMP say they’ve received three reports of youth being extorted on… Continue reading

Fines for contravening the fire ban start at $1,150 and could go as high as $100,000. File photo
Yukon campgrounds will open on May 1 this year. (Black Press file)
Yukon campgrounds to open early

Yukon campgrounds will open on May 1 this year. The early opening… Continue reading

A Housing First building on Fifth Avenue and Wood Street will be taken over by the Council of Yukon First Nations and John Howard Society later this month. (Crystal Schick/Yukon News file)
CYFN, John Howard Society take over downtown Housing First residence

The organizations have pledged culturally appropriate service for its many Indigenous residents

Legislative assembly on the last day of the fall sitting in Whitehorse on Nov. 22, 2018. Politicians return for the spring sitting of the assembly March 4. (Crystal Schick/Yukon News file)
Analysis: What to expect in spring sitting of the legislature

They’re back on March 4, but election speculation is looming large


Wyatt’s World for March 3, 2021.

A man walks passed the polling place sign at city hall in Whitehorse on Oct. 18, 2018. The City of Whitehorse is preparing for a pandemic-era election this October with a number of measures proposed to address COVID-19 restrictions. (Crystal Schick/Yukon News file)
City gets set for Oct. 21 municipal election

Elections procedures bylaw comes forward

A rendering of the Normandy Manor seniors housing facility. (Photo courtesy KBC Developments)
Work on seniors housing project moves forward

Funding announced for Normandy Manor

Tom Ullyett, pictured, is the first Yukoner to receive the Louis St-Laurent Award of Excellence from the Canadian Bar Association for his work as a community builder and mentor in the territory. (Gabrielle Plonka/Yukon News)
Tom Ullyett wins lifetime achievement award from the Canadian Bar Association

Ullyett has worked in the Yukon’s justice ecosystem for 36 years as a public sector lawyer and mentor

The Blood Ties outreach van will now run seven nights a week, thanks to a boost in government funding. Logan Godin, coordinator, and Jesse Whelen, harm reduction counsellor, are seen here on May 12, 2020. (Crystal Schick/Yukon News file)
Blood Ties outreach van running seven nights a week with funding boost

The Yukon government is ramping up overdose response, considering safe supply plan

Ranj Pillai speaks to media about business relief programs in Whitehorse on April 1, 2020. The Yukon government announced Feb.25 that it will extend business support programs until September. (Crystal Schick/Yukon News)
Government extends business relief programs to September, launches new loan

“It really gives folks some help with supporting their business with cash flow.”

Whitehorse City Hall. (Joel Krahn/Yukon News file)
A look at decisions made by Whitehorse City Council this week

Bylaw amendment Whitehorse city council is moving closer with changes to a… Continue reading

Susie Rogan is a veteran musher with 14 years of racing experience and Yukon Journey organizer. (Yukon Journey Facebook)
Yukon Journey mushers begin 255-mile race

Eleven mushers are participating in the race from Pelly Crossing to Whitehorse

Legislative assembly on the last day of the fall sitting in Whitehorse on Nov. 22, 2018. As the legislature prepares to return on March 4, the three parties are continuing to finalize candidates in the territory’s 19 ridings. (Crystal Schick/Yukon News file)
Nine new candidates confirmed in Yukon ridings

It has been a busy two weeks as the parties try to firm up candidates

Most Read