Adventive species

An adventive species is a species that has arrived in a new locality. It may have had help from humans as an introduced species or it may not.

The term is now used by some writers in a more restricted sense than its initial usage. The earliest and most widespread concept among biologists is that of a species that has arrived in a specific geographic area from a different region (without further caveats). This is the forerunner of the term 'non-indigenous species', although it lacks the frequently invoked basis of the word 'introduced', which means different things to different writers. In this sense, the cattle egret (Bubulcus ibis), which arrived in North America by natural range expansion, the black rat (Rattus rattus), which is believed to have arrived as a hitchhiker aboard ships, and the kudzu vine (Pueraria lobata), which was introduced deliberately by humans, are all adventive species and have established populations. Common adventive species include herbivorous insects.