Invasive alien species

According to the Convention on Biological Diversity, invasive alien species are species whose introduction and/or spread outside their natural past or present distribution threatens biological diversity. For a species to become invasive, it must:

  • successfully out-compete native organisms,
  • spread through its new environment,
  • increase in population density and
  • harm ecosystems in its introduced range.

Invasive alien plants can cause serious economic, social and environmental damage.

  • They threaten human health and safety.
  • They harm natural ecosystems by altering their composition and compromising their sustainability.
  • They reduce forest productivity and regrowth.
  • They disrupt agriculture.
  • They hinder recreational activities.

NCC lands

In 2005, we recorded 67 species of invasive alien plants on our lands. Ten of these species are considered to be extremely invasive. Below is the number of alien species recorded in each sector.

  • NCC urban lands (Ontario and Quebec): 34
  • Greenbelt: 23
  • Gatineau Park: 21

In total, alien species have invaded 30 percent of the area of high-value natural habitats on NCC urban lands.

Next steps

We are continuing to monitor trends with respect to the size of the populations and colonies of invasive alien plants in natural habitats and high-value ecosystems.

Management of invasive alien plants

Our projects are based on three areas of action in the fight against invasive alien plants