Definitions of "invasive non-indigenous species have been inconsistent", which has led to confusion both in literature and in popular publications (Williams and Meffe 2005).
The large number and current complexity of terms makes interpretation of some of the invasion biology literature challenging and intimidating.
Exotic, alien, transplanted, introduced, non-indigenous, and invasive are all words that have been used to describe plants and animals that have been moved beyond their native ranges by humans (Williams and Meffe 2005), along with other terms such as foreign, injurious, aquatic nuisance, pest, non-native, all with a particular implication.
Even the use of what seem to be simple, basic terms to articulate ecological concepts "can confuse ideological debates and undermine management efforts" (Colautti and MacIsaac 2004).
Attempts to redefine commonly used terms in invasion biology have been difficult because many authors and biologists are particular to a favorite definition (Colautti and MacIsaac 2004).