When Nature Boy took down the backyard thicket of Himalayan blackberries, he gave little thought to what would come after.
Thousands of broom and Daphne laureola seeds that had lain dormant for decades sprouted. Ivy and periwinkle quickly spread into the gap.
These plants have no place in the ready-made Garry oak meadow Nature Boy envisioned. Quick to grow and become established, these species handily outcompete native sea blush, camas and ocean spray.
That’s what invasive species do. They reproduce easily and spread. They alter ecosystems within the new territories in unpredictable ways.
Local municipalities are preparing strategies to deal with invasive species. One program, called Pulling Together, has volunteers removing invasive plants from Saanich parks and planting native species. In 2010, volunteers helped remove more than 40 dump-truck loads of broom, ivy and other invasive plant material.
It’s easy to be all for broom bashes and ivy pulls, but we’re much less keen on bludgeoning invasive bunnies or squirrels.
The trauma of the University Bunny Wars remains fresh, after all.
But by doing nothing about the Eastern grey squirrel, we value it more than the songbirds whose eggs and nestlings it preys on and the now rarely seen native red squirrels it has bullied out of prime habitat.
Attempts to limit the spread of the American bullfrog fail. The voracious invader eats pretty much any critter it encounters, including cats and small dogs, OK, maybe not cats and dogs, but more problematically, ducklings, fish and frogs. Some of these are threatened species. People continue to release bullfrogs into bullfrog-free ponds and streams, aiding the spread of this animal and abetting the destruction of native species.
Flocks of house sparrows and starlings sweep through every few weeks. We’re not doing anything about them, either, even though they push out native songbirds.
The barred owl that calls from the nearby park also figures on the list of invaders. The bird arrived west of the Rockies in the 1940s.
It isn’t clear how, or if, the owl affects Vancouver Island’s native wildlife, but the bird certainly compounds problems for B.C.’s endangered northern spotted owl, found only in the southwest corner of the province’s mainland.
Aggressive and adaptable, barred owls compete with spotted owls for food and territory. Barred owls also hunt and eat spotted owls.
As was reported recently, wildlife officials began capturing and relocating barred-owl populations from around confirmed spotted-owl sightings in 2008, in an attempt to give the last few spotted owls remaining in the wild some breathing space. Seventy-three barred owls have been moved. Thirty-nine owls that refused to stay away have been shot.
That’s pretty restrained, yet the news made birders squirm.
Of course, if we were talking gypsy moth, the province would be implementing full-on eradication and monitoring programs. If we were talking snakehead fish, ponds would be drained and lakes dredged. But the gypsy moth damages trees, and trees are economically valuable. Snakehead fish, like bullfrogs, devour almost everything that moves, threatening valuable salmon and trout stocks; they also have that disconcerting amphibious ability to travel overland.
The barred owl seems to harm only the shy, reclusive spotted owl, a bird so rare, it exists in people’s imaginations more as an icon of ancient lichen-draped forests than as an actual fluff-and-feather bird.
The spotted owl also doesn’t put money in pockets.
In fact, saving B.C.’s spotted owl requires keeping money out of the pockets of one of the most influential industries. That’s not going to happen.
So we hack at blackberries and broom under the gaze of rabbit refugees from the Bunny Wars, and we listen for the barred owl’s call.
Beneath it all, we wonder vaguely at the absence of the homey chatter and scold of the red squirrel, and the lack of the lovelorn rattle and croak of the Pacific chorus treefrog.
But then, we, too, are an invasive species. We are the most invasive and most ecologically destructive of all.
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