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.

What is an invasive species?
An invasive species is any species (plant, animal or other biological kingdom) that has been introduced, intentionally or casually, into an ecosystem different from that of its origin where it has been able to establish itself and proliferate without control.
Since there are no natural mechanisms that regulate their population in the new ecosystem, such as possible predators or pathogens (viruses, bacteria, parasites, etc.), the invasive species becomes a pest.
Typically, exotic species that are successful in invading a new location are usually generalist species. This means that their diet is varied or that they can survive in a wide range of environmental conditions. Consequently, these species have a great capacity to adapt and colonize new environments, where they manage to reproduce and grow in population.
With globalization, the flow of transportation of objects, animals, plants and humans around the world has facilitated the introduction of invasive species to places where they would not otherwise have reached naturally. This has caused serious problems worldwide, such as the displacement of native species, the alteration of the physiognomy of a region or the spread of new diseases.
The introduction of invasive species is the second cause of biodiversity loss worldwide.
See also: Species
The most invasive species in the world

In the world there are a large number of species that have invaded and modified different environments. Some have had a greater impact on biodiversity and human activities than others.
In 2004, the Invasive Species Specialist Group compiled a list of one hundred of the most harmful invasive alien species in the world. This group is part of the Species Survival Commission of the World Conservation Union (IUCN).
Among the species with the greatest invasion potential are the water hyacinth, the common carp, the zebra mussel and the European rabbit, among others.
water hyacinth
The water hyacinth (Eichhornia crassipes) It is a species native to the Amazon basin (Brazil), in South America, which today is found in more than 50 countries distributed across all continents (except Antarctica).
It was introduced as a decorative plant and as a source of food for livestock. Its seeds were also accidentally dispersed by adhering to the hulls of ships.
Since it grows very quickly, water hyacinth became one of the worst weeds: causes the obstruction of rivers, makes animal life difficult in the water and prevents sunlight and oxygen from penetrating freshwater bodies and reaching other plants. This reduces the biodiversity of freshwater bodies.
Kudzu
The kadzu (Ppueraria montana var. lobata) It is a leguminous plant native to East Asia, Australia and some islands in the Pacific Ocean. It was introduced to North America, South Africa and Europe as a decorative plant and to control soil erosion.
However, being an aggressive, fast-growing vine, It chokes out other plants and changes the appearance of the landscape It even grows on abandoned houses and vehicles. In addition, it is home to other invasive species considered pests, such as soybean rust and the kudzu bug.
common carp
The common carp (Cyprinus carpio) It is a freshwater fish native to Asia and Eastern Europe. Currently, it is one of the most widespread species in the world. It has been introduced as a pet, for food purposes, for sport fishing and to eliminate algae and plants from ponds and wastewater lagoons, among other reasons.
Since it is plays quickly, resists varied environmental conditions and feeds on aquatic vegetation and plankton, affects many native species and fisheries.
Zebra mussel
The zebra mussel (Dreissena polymorpha) is a species native to Eastern Europe and western Russia. It reached the rest of Europe and North America accidentally, transported by ballast water (the water contained in ships to maintain balance during navigation) and the hull of ships.
By feeding on plankton and reproducing rapidly, has displaced many native species that compete for the same food. In addition, it clogs filters and water intake pipes, which affects industrial, agricultural and urban supply.
Something similar happens with the golden mussel (Limnoperna fortunei) in South America.
cane toad
The cane toad (rhinella marina) is an amphibian native to much of America. It was introduced in different countries around the world (for example, Australia, Spain, Cuba, Egypt and Japan) in order to control insect pests of different crops, such as sugar cane.
Being skilled competitors for food and breeding spaces, have displaced many native amphibians. In addition, they secrete a toxic substance that is deadly to domestic and wild animals.
common starling
The spotted starling (Sturnus vulgaris) It is a bird native to Europe, Asia and North Africa. It was introduced in North America, South Africa, Australia and New Zealand to control insect pests and to be traded as pets.
Individuals of this species gather in large flocks that feed on fruits and grains, causing serious agricultural damage. Besides, They are aggressive and displace native bird species by competing for food and nesting sites.
European rabbit
The European rabbit (Oryctolagus cuniculus) It is a species native to southern Europe and northern Africa. It was introduced to all continents (except Asia and Antarctica) to be marketed mainly as food.
The overpopulations of this rabbit are due to its great speed in reproducing and compete effectively for food and shelter. This, added to the fact that they favor the increase in natural predators (such as cats and foxes), has displaced many native species. In addition, they cause significant soil erosion.
Amphibian chytrid fungus
The chytrid fungus of amphibians (Batrachochytrium dendrobatidis) It is a fungus native to South Africa that has been introduced almost all over the world, except Asia. It is believed that the commercialization of the African clawed frog (Xenopus laevis) has caused the dispersal of this species.
This fungus causes a mycosis or infection in the skin of frogs, toads and salamanders that is lethal. In addition, it can interrupt cutaneous respiration and alter the immune responses of these vertebrate animals. So it is one of the main causes of the global decline of amphibians.
Asian longhorned beetle
The Asian longhorned beetle (Anoplophora glabripennis) is native to Asian countries, such as China, Japan, and Korea. It was introduced in North America and Europe as a result of the transportation (by sea) of logs and wooden packaging.
This insect reproduces quickly and feeds on a layer between the bark and the log of trees. By doing so, It makes large tunnels in the wood that weaken them and make it difficult for nutrients to be transported within the trunk. This threatens a large number of urban trees and has economic and ecological consequences.
small indian mongoose
The small Indian mongoose (Herpestes auropunctatus) is native to South Asia. It was introduced to the rest of Asia, Central America and northeastern South America to control rat and snake pests. Above all, it has invaded many tropical islands.
This mammal is a generalist carnivore, that is, it has a very varied diet. This has caused Various species of birds, amphibians, reptiles and mammals are in danger of extinction (such as the Jamaican petrel, hawksbill turtle, pink pigeon and Amami rabbit)). Additionally, it transmits rabies and leptospirosis to humans.
North Pacific starfish
The North Pacific starfish (Asterias amurensis) is native to the waters surrounding Russia, China, Japan and Korea. However, it has reached many other parts of the world, such as the coasts of Australia, through ballast water, by adhere to boats and fishing boats and for the fish trade.
This echinoderm feeds on a wide variety of prey, supports different temperatures and salinity conditions, and reproduces quickly. This affects many native species, such as the spotted handfish, and economic activities, such as salmon farming and oyster production.
References
- Begon, M., Harper, J.L., & Townsend, C.R. (1995). Ecology: individuals, populations and communities (Trans. M. Costa). Blackwell Scientific Publications. (Original work published in 1987).
- Lowe, S., Browne, M., Boudjelas, S and De Poorter M. (2004). 100 of the World's Most Harmful Invasive Alien Species. A selection from the Global Invasive Species Database. Invasive Species Specialist Group (GEEI), Species Survival Commission (SSC) of the World Conservation Union (IUCN).Iucngisd
- Martins, A. (November 4, 2019). 7 of the invasive species that are causing the most damage in Latin America. BBC News World. BBC
- National Ocean Service. (sf). What is an invasive species? National Oceanic and Atmospheric Administration. OceanService
- Mexican Biodiversity. (January 20, 2023). Invasive alien species. National Commission for the Knowledge and Use of Biodiversity. Biodiversity
- World Wildlife Fund Chile. (June 5, 2021). Native, Endemic and Exotic: three important concepts that you should know. WWF
- Rafferty, J.P. (March 5, 2023). Invasive species. Encyclopedia Britannica. Britannica
- Nunez, C. (sf). What is an invasive species? National Geographic Spain. National Geographic
- Hanan Alipi, AM and Mondragón Pichardo, J. (August 29, 2009). Eichhornia crassipes (Mart.) Solms. Water lily. In H. Vibrans (Ed.), Weeds of Mexico. Conabius
- Biodiversity Information System. (sf). Eichhornia crassipes. National Parks Administration. SIB
- Global Invasive Species Database. (2023). Species profile: Pueraria montana var. lobata. Retrieved April 10, 2023 from Iucngisd
- Global Invasive Species Database. (2023). Species profile: Cyprinus carpio. Retrieved April 10, 2023 from Iucngisd
- Global Invasive Species Database. (2023). Species profile: Rhinella marina. Retrieved April 10, 2023 from Iucngisd
- Global Invasive Species Database. (2023). Species profile: Oryctolagus cuniculus. Retrieved April 10, 2023 from Iucngisd
- Global Invasive Species Database. (2023). Species profile: Sturnus vulgaris. Retrieved April 10, 2023 from Iucngisd
- Global Invasive Species Database. (2023). Species profile: Batrachochytrium dendrobatidis. Retrieved April 10, 2023 from Iucngisd
- Global Invasive Species Database. (2023). Species profile: Anoplophora glabripennis. Retrieved April 10, 2023 from Iucngisd
- Global Invasive Species Database. (2023). Species profile: Herpestes javanicus. Retrieved April 10, 2023 from Iucngisd
- Global Invasive Species Database. (2023). Species profile: Asterias amurensis. Retrieved April 10, 2023 from Iucngisd