non-native species that has become established in a region and propagates without human assistance (compare to exotic species. introduced species. and native species).
In biology, naturalisation (or naturalization) is any process by which a non-native organism or species spreads into the wild and its reproduction is sufficient to maintain its population. Such populations are said to be naturalised.
Some populations do not sustain themselves reproductively, but exist because of continued influx from elsewhere. Such a non-sustaining population, or the individuals within it, are said to be adventive.Cultivated plants are a major source of adventive populations.
Naturalised species may become invasive species if they become sufficiently abundant to have an adverse effect on native plants and animals.