FAQ

There are over 200 known alien (introduced) species in the NWT. Some of these species are invasive, though the exact number is not known. About 140 of these alien species are plants, and about 60 are insects.

White and yellow sweet clover are likely the two most invasive species currently found in the NWT. These plant species are known to be spreading along the Liard and Mackenzie River shores and sand bars, where they thrive in sunny areas with low competition from shrubs and trees. These species are now known to invade river margins and sandy and muddy natural habitats in Alaska and Yukon.

There are many species in the NWT that could be considered pests, though most of these cause little real damage. In a given year, over half of the recorded forest damage in the NWT may be caused by just two major forest pest species: spruce budworm and aspen serpentine leaf miner.

Spruce budworm is currently the most serious forest pest in the NWT. Outbreaks of native insects, like spruce budworm, are an expected and normal part of life in the northern boreal forest. However, climate change could alter the location, frequency and intensity of outbreaks of native and invasive alien species. This means that species that have not been serious forest pests in the past could become so in the future. Therefore, monitoring changes in damage caused by all forest insects allows managers to predict impacts on overall forest health.