Inventory of Introduced Plants

In the present study, an introduced plant is defined as follows:

Any plant not belonging to the park's indigenous flora which has been brought to the territory in the recorded past.

An inventory of introduced plants in the park was carried out in 1996 and 1997 by Francis Roy. He inspected the shoreline on 14 islands, a total distance of about 150 km. Among other specifications, the data collected included the species, number of individual plants, surface area occupied, habitat, phenology and height of the plants. The colonies' location was indicated on maps.

Previous studies had listed 40 species of introduced plants in the archipelago. The 1996-97 inventory observed 32 of these 40 species, but recorded an additional 5 previously-unlisted species. Combining the results of different studies, we can say that 45 introduced species have been observed in the park to date.

Plants introduced into the park are mainly found near past and present sites of human occupation (campsites, lighthouses, etc.), as well as on the shoreline, which is essentially the park's entry point. Principal carriers of introduced species are human movement, maritime transport (water, boats, debris), livestock feed imported to the islands before the park's creation, and fauna in general.

There are three main concerns regarding plants of interest:

Purple Loosestrife
Purple Loosestrife
© Parks Canada / J. Pleau
Presence of the Purple Loosestrife

This invasive species was found in one sole location in the park in 1997, with the presence of a dozen or so individuals over an area of 1.5 m being noted. As of 1998, we proceeded to eliminate the species. However, the site is visited annually to ensure that the species does not reappear.

Competition with plants of interest

For the moment, there are no plants of interest that appear to be threatened by the presence of introduced plants. However, particular attention is given to this question when monitoring plants of interest.

Genetic mingling with plants of interest

Studies are necessary to determine whether the risks of genetic mingling between species of interest and introduced species are real. Dandelions (genus Taraxacum ) are particularly targeted as, among the park's five species, four are species of interest and one is an introduced species, with the latter being the most widely reproduced.

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