pests take foothold as temperatures warm in the yukon

How can a plant with a nice name like sweetclover be bad? Yukon wildlife biologist Bruce Bennett can tell you at least three different ways that this invasive species could wreak havoc on Yukon's ecosystems and the environment.

How can a plant with a nice name like sweetclover be bad?

Yukon wildlife biologist Bruce Bennett can tell you at least three different ways that this invasive species could wreak havoc on Yukon’s ecosystems and the environment.

The spread of sweetclover could affect the health of Yukon’s bee populations because bees may feed only from one type of plant and would therefore only get one type of pollen.

Sweetclover could affect Yukon’s waterfowl by crowding the birds’ stopover routes and making them too dense for birds to rest and feed during long migrations.

And, because it grows along Yukon’s highways, it could attract more wildlife to the roads, which could be dangerous for both the animals and the drivers.

“There are many possibilities,” said Bennett. Yukon biologists are not certain how the plant will impact the ecosystem until more studies are undertaken, but one thing is for sure – we are starting to see the effects it will have .

“Sweetclover is with us now and has the potential to spread until it covers every gravelly meadow and riverbank right up to the Arctic,” said Bennett.

Sweetclover is considered an invasive species, which is defined as an alien organism that caused damage to the environment, the economy, or to the health of people.

Invasive plants and animals are the second greatest threat to biodiversity after habitat loss.

But not every alien species is invasive. Of the 154 introduced species in the Yukon, just 20 are considered invasive.

Sweetclover, for example, was introduced to the Yukon through agriculture.

“It’s a green manure,” said Bennett. When put into to farmers’ fields it adds nitrogen and organics to the soil.

But when it spreads outside of farmers’ fields, it can be trouble.

In the past, climate has been a barrier to many invasive species. Colder temperatures have kept plants like sweetclover from, literally, taking root in the Yukon.

Warmer temperatures, shorter stretches of cold weather and increased precipitation, means that conditions for agriculture will improve in the North.

But the conditions that are favourable for growing things like carrots, potatoes and lettuce, are also favourable for invasive plants.

In the past the Yukon would see its first frost by mid-August.

Plants native to the Yukon have adjusted their life cycle so they shut down for the winter before September hit.

Introduced species do not have that internal clock, so almost all of the plant life that is still green along the side of Yukon’s highways come October are introduced species.

In other North American jurisdictions, invasive plants are responsible for habitat damage, loss of subsistence resources, and economic loss.

A conservative estimate shows that Canada spends between $13.3 and $34.5 billion per year controlling the damage from invasive species, according to stats from the Yukon government website.

Through close monitoring, Yukoners can prevent future plant infestations before they become so widespread that control is costly and eradication impossible.

On Wednesday, February 10 at 7 p.m. Bennett will talk about Yukon invasive species and climate change at the MacBride Museum.

This will be the second of five presentations entitled Adaptation and Activism: A Climate Change Lecture Series, which is being presented in partnership with the Northern Climate ExChange, Yukon College and the MacBride Museum.

Next week environmental historian Karine Grenier will speak on Climate Change and Northern Life.

All presentations are free and everyone is welcome.

This column is provided by the MacBride Museum of Yukon History. Each week it will explore a different morsel of Yukon’s modern history. For more information, or to comment on anything in this column e-mail