Invasive Species Week, June 9 – 15, 2014
invasivespeciesweek.com
Fact Sheet – Invasive Species in BC
Invasive species are moving across BC and Canada at a rapid pace
 In Canada, invasive species include at least 27% of all vascular plants, 181 insects, 24 birds, 26
mammals, 2 reptiles, 4 amphibians, several fungi and molluscs, and 55 freshwater fish.
Economic impacts:
 The estimated annual cumulative lost revenue caused by just 16 invasive species is $13-$35 billion.

Invasive species that damage the agricultural and forestry industries result in an estimated $7.5
billion of lost revenue annually.

Through damage to agriculture, forestry, fisheries, and other human enterprises, introduced
species inflict an enormous economic cost, estimated at $137 billion per year to the U.S. economy
alone.

Invasive species cause 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.
In British Columbia:
o Just six invasive plants caused an estimated combined damage of at least $65 million in
2008. With further spread, impacts will more than double to $139 million by 2020.
o
Estimated crop losses in BC cost the agriculture industry over $50 million annually. Species
such as knapweed infest rangelands, reduce forage quality and out-compete desired
species in cultivated fields.
o
A recent economic risk analysis has estimated that zebra and quagga mussel would create
costs of $21.7 million per year in BC in damages to infrastructure, hydropower facilities,
water extraction activities and recreational boaters, beside significant impacts on native
fish stocks.
Environmental Impacts
 Compared to other threats to biodiversity, invasive introduced species rank second only to habitat
destruction, and are a greater threat to native biodiversity than pollution, harvest, and disease
combined.

Of all 1,880 imperiled species in the United States, 49% are endangered because of introduced species.
Social Impacts
 Invasive plants impact human health and safety by obstructing sightlines and road signs along
transportation corridors, causing skin burns and dermatitis, and increasing allergies. For example:
o 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.
o
Scotch broom (Cytisus scoparius) causes seasonal allergies and hay fever.
o
Tansy ragwort (Senecio jacobaea) can be toxic to horses and livestock.
o
Japanese knotweed (Fallopia japonica) obstructs sightlines.
Invasive Species Council of BC – www.bcinvasives.ca