Kristina Swerhun: Invasive species threaten biodiversity in Sea to Sky corridor

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      By Kristina Swerhun

      Every year, invasive species cost the Canadian taxpayer in the order of a few billion dollars. Invasive species are brought to Canada either accidentally or intentionally. These plants have the ability to establish quickly and are highly competitive due to prolific seed production, deep taproots, or early flowering. Because they arrive in Canada without their natural predators to keep them in balance, they can spread rapidly, forming dense patches over large areas and often displacing native plants.

      Invasive species are the second biggest threat to global biodiversity, after habitat destruction by land clearing. By profoundly limiting biodiversity, invasive plants threaten vital elements that support ecological integrity of coastal ecosystems. They negatively affect the habitat of wild animals; increase fire hazards; accelerate erosion, leading to siltation; and can destroy roads and other built environments. They also cause other problems related to human and animal health, as well as crop or forage reduction.

      There are many things individuals can do to help fight this problem. One is to avoid being a cause of the spread. When doing outdoor activities, such as biking, hiking, horseback riding, off-roading, hunting, or fishing, regularly inspect and wash equipment, clothing, gear, pets, and horses for invasive plant fragments and seeds. Dispose of these fragments and seeds in a plastic bag in the garbage. Also, choose parking and staging areas that are weed-free, and avoid weed-infested areas.

      Be careful when disposing garden waste. Although it might seem like a good idea to “recycle” your garden debris into a natural area, what you’re really might be doing is introducing plants that can smother, choke, and otherwise ruin parks, greenways, and other green space needed by wildlife—and enjoyed by people.

      Don’t intentional introduce an invasive as a garden ornamental. Many invasive plants got their start in someone’s garden. Most were exotics brought from other parts of the world. But here, they don’t have the same natural predators or checks to keep them under control, and they literally go wild.

      Different regions in B.C. have different invasive species issues. Vancouver Island, for example, has existing invasive plant infestations which are estimated to be in the tens of thousands. Other areas, like the Sea to Sky corridor, are in relatively good shape, but there is still urgency in dealing with invasive threats: to eliminate invasive species or keep them in check before they become uncontrollable.

      The threats due to invasive species provided the impetus to form a brand new not-for-profit group in the Sea to Sky corridor to help control the spread of invasive plants and animals. Called the Sea to Sky Invasive Species Council, the group will work in cooperation and coordination with other regional invasive committees in a provincewide effort to minimize the negative impacts caused by the introduction, establishment, and spread of invasive species.

      What sets the group apart from other “weed committees” across the province is that its work includes invasive animals as well as plants. The group’s goals for the summer are to gather information on the occurrence of invasives in the Sea to Sky corridor by working with local residents, groups, and governments; identify priority species; and organize control work on those species.

      Examples of invasive species threatening the Sea to Sky corridor include Japanese knotweed and Scotch broom in Squamish, yellow flag iris in Whistler, diffuse knapweed in Pemberton, and purple loosestrife and bullfrogs throughout the corridor.

      Web sites that can help with the identification of invasive species include Invasive Plant Council of B.C., Coastal Invasive Plant Committee, Greater Vancouver Invasive Plant Council, Weeds B.C., and Report-A-Weed. Each region has its own priority invasives, due to the different biogeoclimatic zones and different vectors that spread invasives.

      Kristina Swerhun is the coordinator of the Sea to Sky Invasive Species Council. She can be contacted at