Invasive Species – Concept, examples, origin and consequences

We explain what an invasive species is, which are the most invasive species in the world, where they come from and what problems they cause.

invasive species Indian mongoose
Invasive species reproduce easily and harm native species.

What is an invasive species?

The invasive species (plant or animal) is that introduced, intentionally or by chance, in an ecosystem different from that of its origin. It becomes a pest because it does not have natural mechanisms to survive in the new ecosystem and because of possible predators that can extinguish it.

Consequently, the invasive species develops a great capacity for adaptation and colonization from new places, and generates fertile offspring. Today, the flow of transport around the world of objects, animals, plants and humans, gives rise to invasive species that would rarely develop naturally.

Invasive species they can cause minor problems or major catastrophesFor example, displacing native species, changing the appearance of an area, or spreading new diseases.

The most invasive species in the world

invasive species European starling
Invasive birds such as common starlings affect crops.

Among the ten most invasive species in the world, of plants and animals, the following stand out:

  • The water hyacinth (eichhornia crassipes). It is a species native to the Amazon basin of Brazil, in South America. It was introduced to Africa, Asia, North America, Australia, and New Zealand as a decorative plant, as animal feed, and as part of the aquarium trade. It also moved because its seeds stuck to the hull of ships. It became one of the worst weeds because it clogs rivers, hinders animal life in the water, and prevents sunlight and oxygen from reaching other plants.
  • The kudzu (pueraria montana var lobata). It is native to East Asia and some islands in the Pacific Ocean. It was introduced in North America and Europe, for gardens and as food. It is an aggressive vine that grows very fast and can smother other plants and even kill mature trees. It is very difficult to extract it from the ground permanently.
  • The Asian carp. It is a fish native to Russia and China, which was introduced in North America and Europe as food, for the pet trade and for sport hunting. It is a problem because it reproduces quickly and because, due to its great appetite, it eats the food of other native species and the eggs of other species of fish.
  • The zebra musseldreissena polymorpha). It is native to the Caspian, Aral, Azov, and Black Sea Seas. It was introduced in Russia, Europe and North America, as a result of ballast water (the water that ships contain and that helps them maintain balance during navigation) and by adhering to the outer walls of ships. It is a problem because it eats plankton (a food source for native fish) and because it reproduces rapidly.
  • The Cane Toadrhinella marina). It is native to Central America and was introduced to different warm climate countries around the world, for example Australia, to control crop pests. It is a problem because it has a very strong defense mechanism (it emits a toxic substance through sweat), which affects plants and animals.
  • The European or common starling (sturnus vulgaris). It is native to Europe, Asia, and North Africa. It was introduced to North America, South Africa, Australia and New Zealand to control pests and to market as a pet. It is grouped in large flocks of birds that feed on fruits and grains, causing serious damage to farms. In addition, it is aggressive and alienates other species of native birds.
  • The European rabbit (oryctolagus cuniculus). It is native to southern Europe and North Africa. It was introduced on all continents (except Asia and Antarctica) to be marketed as food. Overpopulation of the species was generated due to its great speed to reproduce. In addition, it eats so much that it has displaced many plant species and competes for food and shelter with native animals.
  • The long-horned beetle (anoplophora glabripennis). It is native to China, Japan, and Korea. It was introduced in North America and Europe as a consequence of the movement (by sea) of logs and wood packaging. It reproduces quickly and feeds on the bark, making it difficult for nutrients from trees to reach their branches. In addition, it makes large tunnels in the wood that weaken the tree.
  • The small Indian mongooseherpestes auropunctatus). It is native to South Asia and was introduced to the rest of Asia, Central America, and South America to control rat and snake pests. It is an aggressive predator and has made several species endangered (such as the Jamaican petrel, hawksbill turtle, pink pigeon, Amami rabbit, and other birds, reptiles, and mammals). In addition, it transmits rabies to humans.
  • The North Pacific Starfish (Asterias amurensis). It is native to China, Japan, and Korea. It was introduced to Australia as a result of ballast water and by attaching itself to boats and fishing vessels. It is a problem because it feeds on almost anything it finds and reproduces very quickly. It has made the spotted fish in danger of extinction.