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Prince Edward Island National Park of Canada

ShoreLINES: Heritage Notes from Parks Canada's Special Protected Places in PEI - Fall 2012

Top 5 Ecosystem Invaders in PEI National Park

Garlic Mustard © Parks Canada

PEI National Park spans 42 kilometers along the island’s north shore between New London and Tracadie bays and includes the tip of the Greenwich peninsula in St. Peters Bay. This small coastal park contains many habitats, including sand dunes, beaches, wetlands and forests.

Like many protected areas, the ecosystems in PEI National Park face many threats, both from outside and within the park. To ensure the park remains healthy so that it may be enjoyed by future generations, Parks Canada is taking measures to minimize the impact of threats on its ecosystems.

What is an ecosystem?

An ecosystem is a biological community and includes all of the non-living factors that influence that community. It consists of animals, plants, microorganisms, air, water, and minerals. All of the ecosystem components co-exist in balance and are interconnected.
In ensuring the ecosystems in PEI National Park are healthy, Parks Canada works to maintain ecological integrity. Ecological integrity is a term used to describe ecosystems that are self-sustaining and self-regulating. For example, they have complete food webs, a full complement of native species that can maintain their populations, and naturally functioning ecological processes (energy flow, nutrient and water cycles, etc). One of the threats to ecological integrity in PEI National Park is the presence of invasive alien plant species.

What is an Invasive Alien Species?

“Alien” species are species that have been introduced to an area that is outside their natural range. In some cases, alien species can overwhelm their ecosystems with extreme abundances. When this happens, the alien species is referred to as an invasive alien species.

The presence of invasive alien species in an ecosystem can result in the displacement of native species and a loss of their function; such as, providing habitat or food resources for wildlife. This can have long lasting and devastating impacts, especially for species that specialize or rely on a specific undisturbed area or habitat type.

Maintaining Ecosystem Health in PEI National Park

As part of its mandate to protect and present ecological integrity, Parks Canada has taken on a battle with alien invaders. In the past five years, effort has been concentrated on monitoring the early detection of a short list of five invasive alien species in areas considered the most at risk in the park. They are:
1. Japanese knotweed
2. Garlic mustard
3. Glossy buckthorn
4. Purple loosestrife
5. Scotch pine

One of the biggest challenges is that these plants can easily be unknowingly introduced as seeds carried on shoes, tires or transported in materials such as soil or roadside fill. The early detection of these ecosystem invaders will permit timely action at a stage where the impacts on the ecosystem are not significant. Here is a summary of actions that have been taken to reduce or eliminate invasive alien species populations in PEI National Park.

Japanese knotweed

Through regular monitoring and notification from concerned visitors and neighbours, areas where Japanese knotweed was accidently introduced through road fill were located and successfully treated. Extensive areas of Japanese knotweed in the Greenwich area are currently being treated through tarp and burial techniques.

Garlic mustard

Garlic mustard is treated with a variety of methods, including hand pulling and chemicals. Since its initial detection in 2006, there has been a decline in the abundance of the plant. However, the seeds can be viable for up to five years in the soil and for this reason, repeated and constant attention is required to gain control of the spread. There remains a core area within the Green Gables golf course that requires attention.

Glossy buckthorn

Glossy buckthorn has proven to be widespread in the forests and hedgerows of the Cavendish area. To control the spread of this species, action in the form of hand pulling and even bark girdling on larger trees is necessary.

Purple loosestrife

Purple loosestrife is present in some of the park’s wetlands; however with annual attention and removal of plants prior to shedding seeds, it has remained under control.

Scotch pine

Scotch pine trees are easy to detect and treat, with simple stem cutting being all that is required to reduce abundances. Significant gains in the removal of Scotch pine within the park’s forest ecosystem are planned for the fall of 2012.
During the summer of 2012, a great deal of progress was made in controlling and reducing invasive alien plant species abundances in the park. Hundreds of kilograms of garlic mustard and glossy buckthorn were removed from the park and large strides were made in controlling the very invasive Japanese knotweed. With Parks Canada’s continued efforts to reduce the presence and spread of invasive alien plant species, PEI National Park’s ecosystems will remain healthy and intact.

You can help!

• Learn more about identifying invasive species identification;
• Watch for the top five alien invaders during your visit to PEI National Park and report your sightings to park staff,
• Landowners can survey and control invasive alien species on their properties
• Visit for more information

For more information or to contact Parks Canada, please e-mail us at: or call us at (902) 566-7050.