Invasive Species

Invasive species are the second most significant threat to biodiversity after habitat destruction by land clearing, according to the International Union for Conservation of Nature (IUCN 2017). The economic and environmental impacts of invasive species are also significant.

Invasive species grow rapidly, are hard to get rid of, and out-compete native species. Because they arrive in Canada without their natural predators to keep them in balance, invasive plants and animals can spread rapidly. Specific threats include:

• Decreased biodiversity;
• Altered water flow and leading to erosion and/or less available water;
• Creating and increasing the fire hazard;
• Damage to roads and other built structures;
• Reduction of crop yield;
• Recreational and tourism trails/areas choked by invasive monocultures;
• Decreased property values; and
  a loss of medicinal plants and cultural practices (loss of wild edibles, loss of habitat for wildlife and fish).

Invasive plants and animals spread a variety of ways, including:

• Dumping of garden debris into parks, ditch or wild areas.
  Purchasing and planting invasive plants for ornamental purposes.
• Release of domestic pets (e.g., bunnies and goldfish).
• Not cleaning, drying and draining boats and aquatic equipment before relocating.
• Seeds transport by wind, water, animals, vehicles, soil movement, equipment and humans.
• Transport of root fragments or stollens during the movement of gardening materials, soil or equipment.

The District of Squamish’s highest priority invasive species are Japanese Knotweed, Giant Hogweed, and Yellow Flag Iris, all of which are on the BC Weed Control Act’s Noxious Weeds List.

These species grow and spread aggressively, are highly competitive, difficult to control, and can be highly destructive to natural resources, infrastructure, industry, and human health.

Negative impacts:

• Giant Hogweed causes severe burns to those who come into contact with it and may cause blindness.
• Japanese Knotweed damages infrastructure, reduces the structural integrity of dikes and streamside banks, accelerates erosion, impedes traffic sightlines, and devastates riparian systems. In the United Kingdom, the presence of Japanese Knotweed has now led to reduction of property value and refusal to mortgage.
• Yellow Flag Iris grows in water as dense thickets and blocks drainage.

Currently, there are more than 9 hectares of Japanese Knotweed on municipal land in the District of Squamish (based on 2010 data). Mapping shows that Japanese Knotweed and aforementioned species are spreading, and locations are increasing each year.

The Sea to Sky Invasive Species Council undertakes a control program for Japanese Knotweed (Fallopia japonica), in partnership with various landowners including the District of Squamish.

Learn more about the program

The District of Squamish works closely with the Sea to Sky Invasive Species Council, and contributes annually to the organization.

These funds are successfully leveraged by SSISC to obtain additional funding, and used to develop programs that both benefit our community and provide direct support to District of Squamish staff to manage invasive species.

Some of the programs include the Japanese Knotweed Pesticide Control Program, the Invasive-Free Certification Program, Rebate Program for Invasive Plant Control on Private Land, and Community Weed Pulls.

For more information:

Sea to Sky Invasive Species Council website

   Japanese Knotweed Treatment Program