Colonization can be a biological process as well a cultural one. As Europeans settled Turtle Island, they brought their entire ecosystem with them, introducing scores of non-native species to the continent. A non-native species is a species living outside its native distributional range, which has arrived there by human activity, either deliberate or accidental. Non-native species which are harmful to a local ecosystem are called invasive species. The term “invasive” is used for the most aggressive species. Although the numbers vary widely, some of the current research estimates that there are approximately 50,000 non-native species in the United States today. However, of that 50,000 species, approximately 4,300 are considered invasive species 1. These species grow and reproduce rapidly, causing major disturbances to the areas in which they are present, and threatening biodiversity. Approximately 42% of threatened or endangered species are at risk due to non-native, invasive species 2.
Non-Native Plant Species in North American Forests