CFB SHILO — It’s a battle spanning more than 90 years — how to control biological invaders taking over the training range at CFB Shilo.
Between 1990 and 1995, a number of biocontrol insects have been released at 375 sites to ward off the advances of the invasive leafy spurge. The bright yellow flowered plants grow quickly and use up resources before native plants can put in deep roots.
“We will never get rid of this,” base biologist Sherry Punak-Murphy said. “But what we want to see is the spurge and prairie in balance.”
The first observation of leafy spurge dates back to 1920, disproving a local urban legend.
“A lot of people thought the Germans brought it over, but that’s just not true,” Punak-Murphy said, adding the 70-year head start for the spurge has made recent efforts all the more difficult for newcomers to notice.
The biologist started as a summer student on the base in 1990, being involved with the biocontrol program from the start. She has seen first-hand the impact insects like the tiny flea beetle have made since it was introduced on the land.
“We’ve measured the density in spurge and the native prairie,” Punak-Murphy said. “The flea beetles have allowed the prairie to come back.”
Checking her handheld net, Punak-Murphy notices an abundance of flea beetles in an area far from the insect’s original release site.
“The fact that they’re here means they’re moving,” she said.
The flea beetles’ larvae gets into the root system of the leafy spurge and while it doesn’t kill the plant, it noticeably stunts the growth.
Another game-changer is the spurge hawk moth, a brightly patterned caterpillar that eats leafy spurge — and eats a lot.
Another spurge-fighting agent is the leaf-tying moth. As a tiny caterpillar, the insect pulls together the spurge leaves to create a sticky cocoon, once again shortening the plant’s lifespan and increasing the space for native prairie to thrive.
But Punak-Murphy warns plants aren’t the only victims of spurge.
“Cattle and horses get blisters in their mouths,” Punak-Murphy said, squeezing out an oozing white nylon chemical from a spurge stem that causes the lesions and taints milk.
Since the Canadian Forces are mandated to protect the environmental well-being of the area as a whole, measures such as chemical sprays are out of the question.
“Whatever we would spray would kill other broadleaf plants,” Punak-Murphy said.
Environmental officer Ross Erickson makes sure toxin levels in the heavily used military area remain safe. Erickson tests 30-40 different groundwater wells each year and so far hasn’t seen negative results under the surface.
“We still have to see if there’s any impact from training,” Erickson said.
In some cases, such as the new grenade range at Shilo, areas have been covered in gravel to prevent any toxins leeching from unexploded ordinates.
“It’s sustainability that we’re looking for now when we build,” said Capt. Steve Sloat, who is a Range Control Officer. “Canadian Forces has to keep training but we’re also stewards of the land so we need to manage the two.”
Now any unexploded grenades are reported before training continues, preventing the off-chance of forgotten materials that could taint the soil. All military vehicles carry “spill kits” with mats, trays and bags for different uses to prevent any leaked oil affecting the environment.
Sloat said another large threat to the base are trespassers, who typically travel on all-terrain vehicles from the Spirit Sands area and Spruce Woods. Most of the entry areas are outlined with a thick red line indicating “danger” on the map.
“We can be conducting live firing at any time in those areas,” Sloat said. “But we see the tire tracks all the time — for them the fireguards are highways.”
Financial consequences include a hefty government fine, but the real threat joy-riders pose is to fragile biocontrol initiatives.
“They’re more likely to take things out like leafy spurge,” said Lori Truscott, CFB Shilo’s public affairs officer. “These are environmentally sensitive areas ... and we’re trying to be conscious of our farming neighbours.”
All military vehicles entering and leaving the training range are washed thoroughly to ensure the invasive plants aren’t carried to other prairie areas.
“It’s something guys on (all-terrain vehicles) don’t think about,” Sloat said.
Republished from the Brandon Sun print edition June 30, 2012