We explain what an endemic species is and some examples. Also, invasive, native and endangered species.
What is an endemic species?
An endemic species is any species (animal, plant or other biological kingdom) that lives in a restricted geographical region and, therefore, cannot be found naturally outside that distribution area.
The relationship between the species and its distribution area is called endemism and is independent of geographic scale. It can refer to a specific place, such as a lake, an island, a country or a continent, or also to a certain type of climate or relief.
For example, the jaguar lives from Mexico to northern Argentina, so it can be said that it is endemic to the Neotropics. On the other hand, the pygmy raccoon has a more limited distribution since it lives on the Island of Cozumel (Mexico), and the greater snooping frog only lives in El Pedregal (Mexico City).
The distribution area of an endemic species is one that has the appropriate conditions for its survival A river, an ocean or a mountain range are some natural barriers that delimit these restricted areas and prevent endemic species from dispersing to other sites. In fact, the islands are the places with the most endemic species due to their geographical isolation.
Any disturbance of the habitat in which an endemic species lives can bring it to the brink of extinction, due to its high degree of adaptation to the conditions of the region and the impossibility of dispersing. This can occur, for example, when a pathogen or invasive species enters the environment, or when its climate or physiognomy is altered.
Endemism is fundamental in the composition of the planet's biodiversity, since it allows the variety of species and the proliferation of life. Furthermore, it is key to process of speciation, that is, the evolution and origin of the different species as a consequence of their geographical separation and adaptation to specific environmental conditions.
See also: Adaptation of living beings
Differences between an endemic species and a native species
Generally, all endemic species are considered native species because they are native to the region in which they live. However, both terms are not synonymous.
Many native species do not have a restricted distribution as they may have dispersed from their original range. This may have occurred naturally or by human action. In that case, the species is considered exotic in the region where it was introduced.
On the other hand, the term “endemic” not only applies to the species, but can also be used for higher or lower taxa, such as genera, families or subspecies. For example, the genus Butia is endemic to east-central South America, that is, all palm trees of this genus live only in this region.
Types of endemism
Endemisms can be classified taking into account the distribution or history of the species or taxon.
Depending on the distribution of the species under study we can talk about:
- Microendemism. This term is used when the species has a very restricted area of distribution.
- Quasi-demism. This term is used when the species' range extends slightly beyond the established boundary (e.g. a country) due to continuity of habitat.
- Semi-endemism. This term is used when the species is endemic to a country or region only during one time of the year.
Depending on the history of the species or taxon under study, we can speak of:
- Paleoendemism. It refers to a taxon or group of species that originally had a broader area of distribution but that today is restricted to a more limited area.
- Neoendemism. It refers to a more recent taxon (in evolutionary terms) that is restricted to a certain area but could expand.
Examples of endemic species
The size of the species and their ability to disperse are usually related to their endemism. That is why many species of insects, amphibians and reptiles are endemic.
However, there are also invertebrates and fish endemic to a particular river, lake or other body of water, as well as plants, birds or mammals endemic to a particular island, continent or other geographical region.
Some examples of known endemic species are:
- dragon tree (Dracaena draco). It is a tall tree with rough bark, endemic to the Canary Islands (Spain), Madeira (Portugal) and Cape Verde archipelagos, northwest of Africa. There is also a subspecies of this tree endemic to Morocco. It is considered a threatened species.
- Iberian lynx (Lynx pardinus). It is a carnivorous mammal endemic to the Iberian Peninsula. It is the most endangered feline species in the world, although conservation efforts are achieving the recovery of its populations.
- Junco de Guadalupe (Junco insularis). It is a bird endemic to Guadalupe Island (Mexico), more precisely to the cypress forest, located in the north of the island. Its population is very small, which makes it vulnerable to extinction.
- Loa Frog (Telmatobius dankoi). It is an amphibian that has a microendemic distribution, since it is only found in Las Vertientes de Calama, in the Antofagasta Region (Chile). It is one of the most endangered amphibians in the country.
- St. Kitts giant tortoise (Chelonoidis chathamensis). It is a large reptile that is endemic to San Cristóbal, one of the islands of the Galapagos archipelago (Ecuador). Its population has decreased by more than 80% in the last 180 years, which is why it is considered an endangered species.
- sea cow (Phocoena sinus). It is a marine mammal that has the most restricted distribution, since it is only found in the biosphere reserve created in the Gulf of California. This species is considered critically endangered.
Endangered species
The death of an entire species is called extinction, that is, the disappearance of all the individuals that make it up. Endangered species are those that are at risk of disappearing in the near future. These species are often protected by environmental organizations and international treaties.
Throughout the history of planet Earth, and as a result of climatic, geological and chemical changes in the ecosystem, five mass extinctions occurred, evidenced in the geological fossil record. It is currently considered that we are facing a sixth mass extinction, as a direct and indirect consequence of human activities.
In general, endemic species are vulnerable to extinction. This is due, on the one hand, to their high degree of adaptation to the conditions of the place where they live. And on the other hand, the inability to disperse and expand into new regions.
Therefore, climate change, habitat destruction, the introduction of invasive species, indiscriminate hunting and logging, and pollution, among other factors, have put many endemic species across the planet in danger of extinction.
References
- Heimbuch, J. (February 10, 2022). What's the difference between native and endemic species? treehugger
- Burlakova, LE, Karatayev, AY, Karatayev, VA, May, ME, Bennett, DL, and Cook, MJ (2011). Endemic Species: Contribution to community uniqueness, effect of habitat alteration, and conservation priorities. Biological Conservation144(1), 155-165. Doi.org
- World Wildlife Fund Chile. (June 5, 2021). Native, Endemic and Exotic: three important concepts that you should know. WWF
- Mexican Biodiversity. (March 13, 2023). Distribution of species. National Commission for the Knowledge and Use of Biodiversity. Biodiversity
- Mexican Biodiversity. (April 26, 2022). Endemic species. National Commission for the Knowledge and Use of Biodiversity. Biodiversity
- Federal Attorney for Environmental Protection. (March 9, 2020). Endemic species in Mexico. Government of Mexico.
- Noguera Urbano, EA (2017). Endemism: differentiation of the term, methods and applications. Mexican zoological act33(1). Scielo.org.mx
- Velazco, SJE and Insaurralde, JA (2020). Butia, a genus endemic to South America. In NI Hilgert, ML Pochettino and JE Hernández Bermejo (Eds.). NUS palm trees in southern South America (pp. 117-122). Ibero-American Program of Science and Technology for Development. Cyted
- Arbolapp Canarias. (sf). Dracaena draco. Arbolppcanarias
- World Wildlife Fund Spain. (sf). Iberian lynx, the most endangered feline on the planet, is moving away from extinction. WWF
- Ministry for the Ecological Transition and the Demographic Challenge. (sf). Doñana: The Iberian lynx (Lynx pardinus), the large Mediterranean cat. Mytec
- Roth, A. (September 17, 2019). The vaquita porpoise is on the verge of extinction. National Geographic Latin America. Nationalgeographicla
- Arteaga, A and Guayasamin, JM (2020). Chelonoidis chathamensis. In A. Arteaga, L. Bustamante, J. Vieira and JM Guayasamin (Eds.) Reptiles of Ecuador: life in the middle of the world. Indo-America Technological University. Doi.org
