It's a bucketing rain in Vancouver. Not unusual for late October, but it's a miserable time to be looking for ants as biologist Sean McCann and I zigzag backstreets and wheel through roundabouts en route to the Arbutus corridor community gardens. Parking at the intersection of a cross street and the Canadian Pacific Railway right-of-way in which they reside, we cross to the gardens, still filled with unharvested bounty — squash and pumpkins, grapes and berries, and, of course, a hundred varieties of kale. Amidst the plots stand amateur greenhouses made of clear plastic, vine and tomato trestles, stakes and fences. The contemporary bricolage, however, belies the gardens' age, something more easily ascertained by the presence of five-metre fig trees and other multi-generational plants. Given the sustainable use of this greenspace over the past few decades it's hard to see CP's sudden decision to oust the gardeners as anything but punitive posturing aimed at securing a better land settlement from the city. But we're not here for politics.
McCann — a capable researcher who's worked on everything from mosquitoes, to tropical raptors, to black widow spiders — makes his way to a small plot of grass between the gardens and the tracks. There's a stack of white plastic patio chairs to one side and an elevated fire pit in the centre. McCann rolls a large rock at the base of the pit toward him. Underneath, moist, rich soil is riven by a labyrinth of tiny trails, most of which are swarming with small, orange pin-pricks of life. I feel a hot needle on my bare leg before McCann can even say, "These are European fire ants."
While I'm surprised how easy it was to find Myrmica rubra, the Lower Mainland's invasive species horror-story du jour, a critter that stole the media limelight from zebra mussels and snakehead fish, McCann — who spent last summer tracking and mapping the spread of this problematic pest (generally referred to as EFA) — is surprised we had to work so hard.
"Usually they find you. Basically, you can just stand on a lawn and if any EFA are present, well... they'll eventually come and sting you."
It's that proclivity, more than anything, that makes these interlopers a serious and growing problem where they've become established.
"Where to start? Probably with residential property problems: if you can't even use, or enjoy, your property any more, then it's a problem," says Dr. Robert J. Higgins of Thompson Rivers University in Kamloops, B.C.'s resident ant expert. "When people use the word 'can't' on the phone, I know they're probably talking about EFA. It simply it drives people out."
With few in Canada working on ants, from time to time Agriculture Canada would send Higgins specimens to identify. Knowing EFA was established in the eastern part of the country, and with no interprovincial restrictions on the transport of soils or plants, Higgins figured it was only a matter of time before he saw it out here. That day came in 2010 when he received some specimens of from Deep Cove in North Vancouver. Once the EFA identification was made and it received some media attention, people began sending samples from all over. Some weren't EFA, but many were; in fact, EFA were in 14 of 24 municipalities in the greater Vancouver area plus Chilliwack, as well as Victoria, Oak Bay, and Courtenay on Vancouver Island.
EFA was first identified in the U.S. in 1900 at the Harvard arboretum, and known from Quebec by 1910, but seemed to pose no real threat. Now, however, in the Greater Toronto Area and other parts of Southern Ontario it has become a serious problem. There'd been virtually no sampling of urban ants in B.C. prior to 2010, but the North Van discovery opened things up. Based on the distribution turning up, Higgins reasoned M. rubra had been in B.C. more than 20 years but was just now coming onto the radar. "Likely because the species isn't that aggressive when it first occupies a new area; the behavioural shift occurs when the densities get high and different colonies are competing."
Which is why McCann was hired by Higgins to run a random mapping program over the summer in various municipalities. "We used apple baiting," he tells me. "We'd put out chunks at every house along a transect through a residential areas, then come back 90 minutes later to see what was on them."
And while they only found three previously unknown EFA infestations, they discovered that a single infestation could cover several blocks. EFA don't play nice with other ants, and easily displace most indigenous species. Further effects on ecosystems are yet unknown, but densities of colonies can reach four/m2, and though the actual nest is about the volume of a grapefruit, it contains an average of about 2,000 workers. McCann has found up to 45 laying queens in a single colony, each of which is capable of establishing its own. The issue for homeowners is that EFA might become a reportable pest, affecting property values. In North Vancouver it's already a source of conflict, with some homeowners suing each other.
"The ant has upscale real-estate preferences," says Higgins. "So you might have an elderly couple who employ gardeners, never go in their yard, and don't worry about ants, living next to someone who's smuggling unregulated pesticides in from the U.S., living next to organic greenies who are horrified at that thought. Then there will be those who think they know who introduced the ants to begin with, and others who blame the person who sent the ants in to be identified."
Naturally, I wonder what this all means. "It means we have no real chance of eradicating them," McCann tells me as we wander the tracks in the Arbutus corridor, spotting EFA right, left and centre on the rotting ties. "So that property, that lawn, that garden is now essentially unusable."
No wonder municipalities are tight-lipped about infestations. It explains why I heard back from exactly none of those that I contacted — fire ants suddenly rival Japanese knotweed in their perceived ability to lower property values and taint development potential. Yet another reason to regulate and monitor the transport of soil fill and potted plants between jurisdictions in the Lower Mainland.
Maybe we were here for politics after all.
Leslie Anthony is a Whistler-based author, editor, biologist and bon vivant who has never met a mountain he didn't like.