Species-based mechanisms right|thumb|Japanese knotweed (Reynoutria japonica) is considered one of the world's worst invasive species. upright|thumb|Cats (here, killing a woodpecker) are considered invasive species in Australia and negatively impact wildlife worldwide.
speCies-bAsed mEchANIsms right|thumb|japanEse KnOTweed (ReynoUTrIa jAPOnicA) Is coNsIdeREd ONE of thE WORlD's WorSt inVasive SpeCies. UprIGHt|thUmb|cATs (hErE, KillINg A wOodpecKer) aRe conSiDereD invasivE specIes in AustRALIa anD NeGatiVELy imPAct wiLdliFE woRlDwiDe.