Enter throughout May!

Taking part is simple. Cash prizes are up for grabs. learn more »

Take Action

May is BC Invasive Species Action Month! learn more »

100 Positive Actions in 1 Day

Take action in Williams Lake! learn more »

Webinar Recording

Calling all gardeners - watch the Bringing Back the Natives Garden Tour webinar.recording learn more »

June 27 Webinar

e-Learning for Realtors and Landscape Architects learn more »

Courses across BC March - May 2018

Read more and register today. learn more »

Watch the recording

Learn about the potential economic impacts of a new BC invasion learn more »

Watch the recording!

Presented by Dr. Jon Bossenbroek, University of Toledo. learn more »

Click here to learn more »

Parrot's Feather

A popular aquatic garden plant that spreads with water currents, animals, boats/trailers and fishing gear. Dense stands can stagnate water, and increase breeding grounds for mosquitoes learn more »

Zebra/Quagga Mussels

These tiny freshwater mussels clog drains, damage infrastructure, and are very costly to control/eradicate learn more »

Giant Hogweed

A towering toxic invasive plant with WorkSafe BC regulations learn more »

European Fire Ant

A tiny ant with a toxic sting learn more »

Purple Loosestrife

An aggressive wetland invader that threatens plant and animal diversity learn more »

Orange Hawkweed

Also yellow, these invasive plants replace native vegetation along roadsides, and threaten areas not yet reforested learn more »

Japanese Knotweed

Grows aggressively through concrete, impacting roads and house foundations learn more »

Spotted Knapweed

A single plant spreads rapidly with up to 140,000 seeds per square metre learn more »

Scotch Broom

An evergreen shrub that invades rangelands, replaces forage plants, causes allergies in people, and is a serious competitor to conifer seedlings learn more »

What are their impacts for BC?

Invasive species are impacting British Columbia in the following ways:

Economic Impacts

The economic impact of invasive species in Canada is significant. According to Environment Canada:

  • The estimated annual cumulative lost revenue caused by just 16 invasive species is between $13 to $35 billion.
  • Invasive species that damage the agricultural and forestry industries results in an estimated $7.5 billion of lost revenue annually. 

The extent of economic costs of invasive species in BC is currently unknown and requires further research. In BC, invasive plants (not including other species) cause:

  • An estimated combined damage (six important invasive plants in BC) of at least $65 million in 2008. With further spread, impacts would more than double to $139 million by 2020 (Source: ISC Report: Economic Impacts of Invasive Plants in British Columbia).
  • Estimated crop losses in BC agriculture industry of over $50 million annually. Species such as knapweed infest rangelands and reduce forage quality. Many other species out-compete desired species in cultivated fields (Source: BC Ministry of Agriculture, Food and Fisheries. 1998. Integrated weed management—an introductory manual).
  • Increased maintenance costs to public parks and private property, devaluing real estate. For example, due to the explosion of leafy spurge (Euphorbia esula), Manitoba has experienced a $30 million reduction in land values (Source: Invasive Alien Plants in Canada Summary Report by the Canadian Food Inspection Agency (CFIA).

Environmental Impacts

Invasive species can alter habitats and disrupt essential ecosystem functions. Invasive plants specifically displace native vegetation through competition for water, nutrients, and space. Once established, invasive plants can:

  • reduce soil productivity
  • impact water quality and quantity
  • degrade range resources and wildlife habitat
  • threaten biodiversity
  • alter natural fire regimes
  • introduce diseases

Invasive species threaten biodiversity and many rare and endangered species are at risk from extinction from non-native invasions of invasive plants and other species. Invasive species can disrupt the natural migrations of wildlife since their habitat, without prevention or intense and costly management, can be damaged or destroyed – with the impacts often irreversible  to the local ecosystem. Prevention is key to any effective management plan.

Societal Impacts

When established in crops or natural areas, invasive plants and/or species can result in: 

  • lost income
  • reduced water quality and quantity (increased erosion and sedimentation)
  • reduced property values
  • damage to private property and infrastructure
  • and loss of traditional food and medicinal plants
  • reduced land and water recreational opportunities
  • increased control and management costs
  • export and import trade restrictions imposed

Invasive plants also impact human health and safety by obstructing sightlines and road signs along transportation corridors, causing skin burns and dermatitis, and increasing allergies. For example:

  • the leaves and stems of giant hogweed (Heracleum mantegazzianum), an escaped ornamental, contain a clear, watery, highly toxic sap that, if touched, can cause hypersensitivity to sunlight resulting in burns, blisters, and scarring of the skin. WorkSafe BC has issued a Toxic Plant Warning for this plant, and many efforts are being made in BC and across Canada to raise awareness of Giant Hogweed.
  • Scotch broom (Cytisus scoparius) causes seasonal allergies and hay fever;
  • Tansy ragwort (Senecio jacobaea) can be toxic to horses and livestock;
  • Japanese knotweed (Fallopia japonica) obstructs sightlines

The impacts of invasive species requires further study in BC. Problems with invasive rabbits on Vancouver Island in metropolitan areas and their destruction to infrastructure, and the American Bullfrog and Grey Squirrel populations competing for resources with their native counterparts in the Lower Mainland are just some examples of invasive species causing damage in BC. Visit the Most “Unwanted” Invasive Organisms section to learn more.