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Invasive Species

1.0 Invasive Species 101

This section outlines some of the basic ecological characteristics of the most common invasive species in Algonquin Provincial Park.


What are they?

An Alien Species or Non-native Species is a species of plant, animal, or microorganism that has been introduced outside of their natural historical or present distribution. Species that were not historically in the park but are now present as a result of human activities would fall into this category.

An Invasive Species is an alien species that causes harm to the environment, the economy, or society, including human health. The worst invasive species typically have high growth rates or reproductive rates, and if left unmanaged will outcompete native species for food or habitat, resulting in ecosystem degradation.

Common characteristics of Invasive Species include:

• Few natural predators
• Adaptable
• Reproduce quickly
• Thrive in disturbed ecosystems
• Out-compete native species for food and habitat


In some areas invasive species have arrived relatively recently, and it is important to limit or eradicate these populations as soon as possible to mitigate their environmental impacts. Preventing the introduction or establishment of invasive species is often the most effective management approach, and therefore education on species identification is crucial. Eradicating new patches of invasive species is also extremely important, as even small populations of invasive species can grow to a seemingly unmanageable size in a short period of time if left unchecked.


Why are they a threat?

Invasive species are a direct threat to protected areas because they have obvious negative effects on the ‘composition and abundance of native species’, and are therefore a negative influence on ecological integrity.

Where an invasive species has taken the place of a native species, they can disrupt food chains and lead to a reduction in biodiversity. For example, if an invasive plant species is displacing a native species that would normally produce food or habitat for wildlife, then the impacts of this invasive species may be felt throughout the ecosystem. Invasive plants in particular are a concern because they can form dense colonies, or are very aggressive competitors, and can quickly choke out native plant species and disrupt ecosystem processes (e.g. forest succession).