Weeds shed light on climate change

Not many people understand the deadly potential of the common European dandelion. In its native environs the well-known weed isn’t much of a…

Not many people understand the deadly potential of the common European dandelion.

In its native environs the well-known weed isn’t much of a problem for anyone but gardeners.

But Taraxacum officinale piggybacked on westward human migration over the past 500 years, and became an invasive species in North America.

“They established in small numbers, and were initially introduced probably to be used for salad greens,” said Benjamin Gilbert, a 33-year-old PhD student from the University of British Columbia who is studying the proliferation of the European dandelion, among other plant species, along the fringes of Kluane National Park.

“There are few native dandelions in the Yukon, and one of them occurs in very similar roadside ditch conditions to the invasive dandelion,” Gilbert said in an interview Monday.

Gilbert was one of eight doctoral students from the Western Hemisphere to win a $90,000 bursary from the Canon National Parks Science Scholarship in December.

He’ll use the money to continue a five-year study of invasive plants in the Yukon.

What’s the big deal? So there’s new plant life in the New World.

Nature adapts.

“One of the fears is that when that European dandelion comes up it will push out the other dandelion, and that diversity the Yukon once had will no longer exist,” Gilbert explained.

“Globally, diversity is basically what allows us to do things like develop new drugs and putting pest resistance into crops by breeding different species.

“That’s the way we use it. And there’s also the ethical consideration. Should we, as a species, be causing other species to go extinct?”

Extinction is a bad thing. Necessary to ecological cycles, perhaps, but when the actions of one species — such as humans with our horticulture and pollution — cause other species to die off rapidly, it’s time to re-evaluate.

Especially when there’s a mass extinction going on.

Prevailing wisdom from paleontologists suggests five major extinctions in the history of life on Earth.

And many predict a sixth extinction is underway.

Current extinction rates are 100 times faster than they should be, said Gilbert.

The prospect of mass extinction is scary, but it also provides an interesting challenge for scientists like Gilbert.

Raised among the forests of southern Quebec and northern Ontario, Gilbert moved west to cultivate his interest in plant life at UBC, where he graduated with a biology degree.

He earned his masters at McGill University in Montreal and started his PhD research on Kluane plants for UBC two years ago.

Not only is the dandelion moving west, but it’s also moving north on the cusp of climate change, said Gilbert.

Invasive species can be harbingers of global warming. Scientists like Gilbert map their migration to determine any overlap with changing climate conditions.

“The Yukon, and in particular the western and northern Yukon, are expected to be really hard hit by global warming,” said Gilbert.

He maintains a research garden just outside Kluane park, between a small airstrip and the Alaska Highway, about 15 kilometres east of Sheep Mountain.

He manipulates samples of Kluane’s native plants, like knick-a-knick, to see how they resist invasive species and to determine the traits of all the plants.

Once his research is completed, he’ll pull the invasive plants out by their roots, “because most of what I do is experimental, and I don’t want to introduce any of these plants into the park and disturb things too much there.”

The question his research seeks to answer is whether or not the native plants are using all the available resources — such as water and sun — and thus be able to out-compete intruders.

 “When we start to see a decline in species X, what we expect is a strong increase in invasive species, so that species X is the one we have to monitor, to watch for invasives coming in and to know when to go into an area and try to take action to eradicate invasives.”

Such actions might include weeding, planting native species or even wielding specific herbicides on hard-hit areas.

Sounds good in theory.

But really, what will counting non-native dandelions do to prevent extinction or global warming?

“When we introduce these species and we see them starting to establish and take over, we don’t know if in the long term that’s going to drive things extinct or not,” said Gilbert.

“And we don’t really have a way of knowing for another 50 to 100 years or 400 years.”

But it makes scientific sense to hedge your bets.

 “Under the idea of climate change, we would expect native communities to be shifting or changing somehow,” said Gilbert.

“If we’re going to monitor the change in those communities, what changes actually would cause more invasive species to come in, versus what species don’t impact them as much.”

Other researchers with the Yukon government are mapping the route invasive species travel from British Columbia into the Yukon.

And Gilbert is also examining how development projects like the Alaska Highway impact the success of invasive species.

Together their research will yield details of the plant invasion.

Some of our long-standing ideas about what the natural world is, aren’t consistent with nature anymore, said Gilbert.

“A lot of what we take for granted in everyday life springs from the fact that we have a certain diversity of life, and that we use it to human benefit.

“It becomes scary when we think then of taking that away.”