Endemic Species

An endemic species is any species ( animal , plant , or other biological kingdom ) that inhabits a restricted geographic region and therefore cannot occur naturally outside that area of ​​distribution .

The relationship between the species and its range 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 inhabits the Island of Cozumel (Mexico), and the greater nosy frog only inhabits El Pedregal (Mexico DF).

The area of ​​distribution of an endemic species is one that has adequate conditions for its survival. A river, an ocean or a mountain range are some natural barriers that define 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 geographic 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 an 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 . It is also key to the speciation process , that is, the evolution and origin of the different species , as a consequence of their geographical separation and adaptation to specific environmental conditions.

Differences between an endemic species and a native species

In general, all endemic species are considered native species because they are native to the region in which they inhabit. However, both terms are not synonymous.

Many native species are not range restricted 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” is not only applied 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 central eastern South America, that is, all the palm trees of this genus inhabit only 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.
• quasidemism _ This term is used when the range of the species extends slightly beyond the established limit (for example, a country) due to the continuity of the habitat.
• Semidemism . This term is used when the species is endemic to a country or region only during one time of the year.

According to the history of the species or taxon under study, one can speak of:

• paleoendemism . It refers to a taxon or group of species that originally had a broader area of ​​distribution but is now restricted to a narrower 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 dispersal capacity 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 endemic plants, birds, or mammals to a particular island, continent, or other geographic region.

Some examples of known endemic species are:

• Dragon tree ( Dracaena draco ). It is a very tall tree with rough bark, endemic to the Canary (Spain), Madeira (Portugal) and Cape Verde archipelagos, in northwest 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.
• Guadalupe Junco ( Junco insularis ). It is an endemic bird of Guadalupe Island (Mexico), more precisely of the cypress forest, located 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 threatened amphibians in the country.
• Saint Christopher 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 been reduced by more than 80% in the last 180 years, which is why it is considered an endangered species.
• Vaquita porpoise ( 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 compose it. 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 . Currently it is 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, the inability to disperse and expand into new regions.

Therefore, climate change, the destruction of habitats, the introduction of invasive species, indiscriminate hunting and logging, and pollution, among other factors , have endangered many endemic species throughout the entire planet. .