Bioinvasion Ecology: Assessing Invasion Impact and Scale

Abstract

Two aspects of assessing the impact and scale of invasions are explored here. First, the argument is made that it is not possible to place introduced species into one of two bins — those with, and those without,“impact” or “harm”. Species invasions lead to a broad and deep sliding scale of alterations in invaded communities, as well as multiple ranges of societal (industrial, economic, social, recreational, health) impact. Second, invasion scale (and thus impact) have been underestimated by historical biases and size biases. A further bias arises out of the selective study of habitats presumed to be more invaded than other habitats. Examples of invasions in many different marine environments are presented.