Agriculture, forestry and fishing hit hardest by spread of invasive plants

Invasive plants in our environment can have a serious economic impact.

Spreading fast, and difficult to contain once established, invasive plants hit the agricultural, forestry and fishing industries hard and the effects of this are felt by all.

AGRICULTURE:

Wheat stem rust is one of the most widespread and damaging diseases of wheat in Canada and the world.

The invasive shrub, Common Barberry, a host to wheat stem rust, has been banned in Canada.

However, while some rust-resistant cultivars are exempt from the ban, scientists are now finding that their offspring are often not rust-resistant and are spreading through gardens.

Oxeye Daisy is another invasive weed that threatens to take over pastures and crops, reducing the quality and amount of food available for livestock and production of seed.

A serious invasive pest, Spotted Lanternfly, is hosted by the invasive Tree of Heaven, and Salt Cedar can lower water tables and increase soil salinity in irrigation systems.

These are just a few examples of invasive plants harming agriculture.

FORESTRY:

Approximately 89 per cent of invasive woody plants in our region originated in the nursery trade and they are threatening our forestry industry.

Norway Maple, European Buckthorn, Black Locust, White Mulberry, Scotch Pine, invasive Honeysuckles and understory species, such as Garlic Mustard are just a few of the invasives threatening our forests.

Some of theses are impacting carbon sequestration, others altering soil chemistry, and some hindering forest regeneration and weakening or damaging native trees including hardwood species like Sugar Maple, essential to the maple syrup industry.

FISHERIES:

In our freshwater bodies, including the Great Lakes, invasive aquatic plants degrade ecosystems, leading to reduced productivity and economic benefits while also decreasing water quality for recreational use.

Aquatic invasives, such as Water Lettuce and Yellow Flag Iris, grow into huge mats of vegetation and block sunlight, so native plants can’t survive, impacting fish and other wildlife that depend on native plants for habitat and nourishment.

Additionally, the thick vegetative mats are dangerous for boaters and swimmers and can restrict water flow for irrigation and in flood control canals.

Several invasive aquatic plants that harm fish habitat have been banned in Ontario, including Parrot’s Feather and Water Chestnut.

Manitoba has broader regulations that include Yellow Flag Iris, Water Lettuce and Water Hyacinth to name a few.

Sadly, Ontario has not regulated these three invasive aquatic plants so gardeners can still purchase them.

The evidence is clear that invasive plants from the horticultural trade impose significant costs on nature, our communities and our economy.

The fact that many of these invasive species are still sold at garden centres means we each have a responsibility to do our research and choose plants that sustain the ecosystems we all depend on.

You too can commit to making plant choices that protect biodiversity, human health and the economy.

Become a supporter, at no charge, of Canadian Coalition for Invasive Plant Regulation (www.ccipr.ca)

Renee Sandelowsky and Helen Varekamp are volunteers for Canadian Coalition for Invasive Plant Regulation