Asian carp: Four Asian carp species are now established in the United States (common carp Cyprinus carpio, grass carp Ctenopharyngodon idella, bighead carp Hypophthalmichthys nobilis, and silver carp Hypophthalmichthys molitrix). After introduction, they spread quickly, became abundant, and hurt native fishes either by damaging habitats or by consuming vast amounts of food.
Wild boar, Feral hog (Sus scrofa): Wild boar are a problem across the Southeastern and Western United States. They can have a significant impact on ground-nesting birds, impact various plant species, increase soil erosion, and can change entire ecological systems.
Island applesnail (Pomacea insularum): Exotic applesnails significantly impact wetland plant communities and rice agriculture due to their voracious grazing. They are also a potential vector for disease transmission to humans and animals.
Nutria (Myocastor coypus): The invasive nutria, or coypu, causes problems in coastal marshes and baldcypress swamps, especially in Louisiana. Nutria feed on the tender roots of plants, seedlings, and saplings, completely stripping vegetation in areas where they are concentrated.
Chinese tallow tree (Triadeca sebifera): The Chinese tallow tree, one of the greatest threats to habitat in the South, rapidly replaces native plants and trees, radically altering marsh, forest, and coastal prairie ecosystems.
Common reed (Phragmites australis): Common reed is native to North America and is one of the most widespread plant species in the world. A strain of reed native to Europe and Asia was introduced to North America in the 19th century. This strain is invasive and replaces native wetland plants to become the dominant species.
Purple loosestrife (Lythrum salicaria): Purple loosestrife is a perennial plant native to Eurasia, where it grows along streams and rivers. When purple loosestrife invades a wetland, the species sometimes becomes more dominant than the original native wetland species.