Invasive species come in many sizes and varieties and include Asian carp, brown marmorated stink bugs, viruses, feral pigs and cogongrass. Invasive species are found around the world and in virtually every environment. They range in size from tiny microorganisms, bacteria and viruses to plants, fish, amphibians and mammals.
Invasive species are organisms that are artificially introduced into environments. They may occupy new spaces after being carried on winds, ocean currents, or through crates and cargo. These organisms often cause harm to their new environments and the native organisms within. Some, such as bacterial strains and viruses, are lethal to local populations, and they spread quickly upon arrival. Invasive species often out-compete native organisms for food and resources, and they may disrupt entire ecosystems. In the United States, Asian carp are among the most common invasive species in aquatic habitats. They were initially imported for domestic use as exotic pets, but they spread rapidly upon escaping into local streams and waterways. They now appear around the nation and deprive native species of food and resources. Ornamental plants, such as cogongrass, are also non-native species in the United States. The first of these grasses arrived through packing materials on ships and planes, and they came originally from Asia. Feral pigs are also invasive species; they are found on farms, and are responsible for spreading diseases such as E. coli.