Once established, ANS threaten biodiversity and can cause a multitude of ecological and economic impacts. These may include: ​

Predation – introduced species may consume native animal/plant populations, causing their decline. ​

Disease – introduced species spread parasites and diseases to native plants and animals.​

Competition – introduced species may compete with native species for limited space and food, often out-competing these native plants and animals.​

Hybridization – introduced species may breed with native species, negatively impacting the genetic purity of native populations.​

Economic Loss – introduced species can cost significant amounts of money to manage and control; may clog water intake pipes of power plants and water treatment plants; impede boating access; cause physical destruction to boat motors; reduce fisheries; decrease property value; and cause several other problems that result in significant economic loss.​