Counter Measures for Alberta’s war against the invasives

By Tim Kalinowski, Staff Writer

There is a war going on in Alberta. It is being fought on the river banks, in the coulees and along the edges of roads and forests. The foe is an implacable one entering into this province by air, land and water. And despite massive efforts, generations of accumulated knowledge and tons of financing, it is a war we might even be losing. So says Barry Gibbs, executive director of the Alberta Invasive Species Council.

“It’s a big challenge,” he confirms. “I’d say in Alberta as a whole we are doing a good job of attacking these (invasive species) problems, but there is lots of room for more opportunities to engage. I think the more we look, the more we find. And that is a concern for us, and there is a lot more we have to do. Overall, at best, I would say we are holding our ground. In some areas we’re losing ground and others we’re gaining.”

Given the proliferation of invasive species entering the province, Gibbs says agencies dedicated to fighting them have to choose their battles carefully.

“There are probably three plants that are of major concern right now,” says Gibbs. “There is Spotted Knapweed, which is coming in more in southwestern Alberta, the Yellow Hawkweed all through the foothills, and Flowering Rush, of which there are a limited number of locations right now, twelve I think, but efforts to control it are very challenging.”

With Spotted Knapweed the threat comes through the air. Gibbs explains.

“It’s no different than many of the invasive plants in that once it gets established it takes over and creates a mono-culture and excludes all the other plants you do want. If you are a farmer or a rancher it excludes your grass. It’s a prolific seed producer and therefore once its get established it is very difficult to control. It’s a big concern; especially in the south of the province.”

Herbicides are generally used to in small areas of infestation where invasives take root, but with Spotted Knapweed, which spreads rapidly over a wide area, other counter measures are being brought to bear.

“Bio-control agents go through a process where they are identified in their native range,” explains Gibbs. “So the places where Spotted Knapweed comes from. You identify an insect in that area that is specific to that plant in its native area; so in Europe and Asia. You test it against plants in Canada under quarantined conditions to ensure it won’t effect any native plants or desirable plants we have here.

“Once those insects get approved by the Canadian Food Inspection Agency, they are released onto the invasive and they will control it. They are a predator of that plant and they will infect that plant. With some invasives the bio-control agent will eliminate the plant and with others it will make them not produce as much seed.

“One bio-control agent we are testing on Spotted Knapweed will go into the seed-head and eat the seeds so you have far less seeds from those plants. These kinds of bio-control agents are already out there. In southern Alberta there is quite a few bio-control agents used.”

For Yellow Hawkweed, whose roots worm their way through the earth suffocating native plants to gain a purchase in Alberta’s foothills country, the counter measures are not so easily decided upon.

“What we are finding is it takes over and forms a complete mat of Hawkweed,” explains Gibbs. “It’s a very interesting plant because it can reproduce by seed, by stolons or by roots. It is very good a colonizing an area. It has wide-ranging impacts through your eco-system.”

“There are a number of things tried on Hawkweed. It’s mostly herbicide because it travels by underground root systems. Pulling it works in small plots where you are diligent and keep going back repeatedly. There are bio-control agents in the development stage, but they will be quite a few years away.”

Heavy grazing is not necessarily a good option for Hawkweed, says Gibbs, but it has worked in other instances where broad leafed plants like Leafy Spurge or Canada Thistle infest a region. It’s another weapon in the arsenal which must always be considered.

“Cattle are predominantly grass eaters. Sheep eat grass and broadleaf. And goats eat predominantly broadleaf and brush. Both sheep and goats have been used extensively to fight weeds and invasives. They have used a lot of sheep on Leafy Spurge. And goats have been used, particularly in urban areas, to control a variety of species like Canada Thistle, as one example.

“When its a deep-rooted plant like Leafy Spurge or Canada Thistle once over isn’t going to do the trick. They need to be coming over that repeatedly so the new growth gets controlled. On a longer term basis, they can be very effective.”

But what if your invader proliferates in waterways, and can’t be controlled by any of the known conventional means? Gibbs says such is the case with Flowering Rush.

“It grows along the edge of water, and it will grow up to three or four metres deep submerged in water,” explains Gibbs. “At first glance, you’d think it was bullrushes, but they colonize an area and then they will grow out into the water too. What happens is if you are a recreationist, you can’t get your boat through it. It gets to be a very thick mat. If it colonizes a beach, you can’t swim in it. It just this thick mass of vegetation.

“The other side of it, is it is a big concern because it is now in Lake Chestermere that it will get into the irrigation canals and start to block the flow and reduce the effectiveness of the irrigation system. There are places in Montana and Idaho that have significant problems. So we know it can be a big problem and we have it in two lakes in Alberta and other small areas.

“There is a requirement to dig or dredge your canals out more often because they keep getting blocked up. And we don’t have a lot of controls. There are some areas we could spray, but other than that there are very limited options.”

For the Alberta Invasive Species Council the war rages on. Gibbs says once these invaders get established they are nearly impossible to completely eradicate. However, there is one factor in all this which can be changed, one factor which could make a difference in the battle against the floaters, the flyers and the creepers.

“We are the problem,” states Gibbs. “People are the ones that spread these things. If we do some simple things like making sure we do a little more research before we bring a garden plant in, or making sure that we clean our boots before we walk out into the parks and in our foothills, or we clean our boats before we launch them— if we do some of those things we can really help solve the issue of the spreading of invasives.”