Endangered Species

We explain what endangered species are, the reasons why they are in danger and some examples of these species.

Polar bear - endangered species
Internationally attempts are made to protect species in danger of extinction.
Summary of Contents

What is an endangered species?

An endangered species is one in which all its individuals are at risk of disappearing from the face of the Earth. This occurs when the total number of individuals is so low that it is not enough to sustain the continuity of the species.

Since the emergence of life on Earth, the evolution and natural selection have caused new species to appear and others to become extinct. However, throughout history there have been five mass extinctions: the last occurred 65 million years ago and wiped out the dinosaurs.

These mass extinctions have involved the loss of a high percentage of biodiversity in a short period of geological time (which can span thousands of years). All of them occurred due to natural causes, such as volcanism, climate changes or the impact of asteroids.

Currently, many researchers believe that We are facing the sixth mass extinction, but in this case due to human causes. The fragmentation and degradation of ecosystems, pollution, indiscriminate hunting and logging, and the introduction of invasive species are some of the human actions that threaten biodiversity.

Therefore, it can be said that the species that are in danger of extinction today are species threatened directly or indirectly by human activities.

Although living beings make efforts to adapt to changes in environmental conditions, Human beings have modified the planet in a more radical and rapid way (especially since the Industrial Revolution) than any other species or phenomenon in history.

Internationally, attempts are made to protect different species in danger of extinction and reverse their situation. For this, its study, evaluation and communication of information is important. At both the federal and global levels, lists of protected species are drawn up and classified according to their level of threat.

The International Union for Conservation of Nature (IUCN) is the international organization with the greatest power on the subject and has drawn up The Red List of Threatened Species. According to this organization, 28% of the species evaluated are at greater or lesser risk of becoming extinct.

Efforts to preserve and recover endangered species are based on the ecological impact of its disappearance cannot be estimated since it can cause the extinction of other species, alter ecosystems and affect the services they provide to humanity (for example, pollination, flood control, water and air purification, pest control, etc.).

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Examples of endangered species

Of the nine subspecies of tiger that exist, three are already extinct.

According to the IUCN, 41% of the amphibians evaluated are at risk of extinction. The same is true for 27% of mammals, 21% of reptiles, 37% of sharks and rays, 28% of crustaceans and 13% of birds. Regarding plants, 34% of conifers and 69% of cycads evaluated are at risk of extinction.

Some of the main endangered species in the world are:

  • The polar bear (Ursus maritimus) The exact number of individuals in the wild is unknown (between approximately 20,000 and 25,000), but polar melting as a result of global warming and environmental pollution harms their endocrine system, their reproduction, and their diet. It is classified as a vulnerable species.
  • The tiger (panthera tigris) In the last 100 years, its population has decreased by 97% and today it is estimated that there are around 3,200 individuals in the wild, which are threatened by illegal trade and the destruction of their habitat. It is classified as an endangered species.
  • The blue whale (Balaenoptera musculus) The largest animal on the planet was on the verge of extinction at the beginning of the 20th century, due to intensive hunting, lack of food and pollution, among other reasons. Currently, although the population is recovering (it is estimated that there are between 10,000 and 25,000 specimens), it is still classified as an endangered species.
  • The hawksbill turtleEretmochelys imbricata) It is one of the most threatened turtle species due to the destruction of its habitat, the loss of the coral reefs where it feeds, and the illegal trade in meat, eggs, and shells. It is classified as a critically endangered species.
  • The Orinoco crocodile (Crocodylus intermedius) This species endemic to the Orinoco River basin (Venezuela and Colombia) is one of the largest crocodiles. Its population is severely fragmented and declining. It is classified as a critically endangered species.
  • The mountain gorilla (Gorilla beringei beringei) There are around 1,000 individuals of this subspecies left, which is a victim of indiscriminate hunting, war, deforestation of its habitat and the transmission of human diseases. It is classified as a critically endangered species.
  • The dragon treeDracaena draco) This species is fragmented among the Canary Islands. Its population has been in decline for many years and it is estimated that there are only around 1,800 individuals. It is classified as an endangered species.

Risk of extinction

Currently, many species are more or less close to extinction. According to studies by the International Union for Conservation of Nature, more than 42,100 species are at some level of threat.

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The IUCN Red List classifies the assessed species into nine categories. To do this, it takes into account different criteria: the size of the population (considered as all mature individuals of the species), its fragmentation, the decrease in the population during the last ten years or the last three generations and the distribution area, among others. others.

The categories in which the IUCN classifies species are:

  • Extinct (Ex) It means that there is no living specimen of the species left, that is, no individual has been found in the known or expected habitat after exhaustive exploration. For example: the last giant tortoise of Pinta (Chelonoidis abingdonii) was collected from the wild in 1972.
  • Extinct in the Wild (EW) It means that the remaining specimens live only in culture, in captivity or as a naturalized population, but the species is no longer found in its natural habitat. For example: the Kihansi toad (Nectophrynoides asperginis).
  • Critically Endangered (CR) It means the species faces an extremely high risk of extinction in the wild. For example: the San Martín marmoset monkey (Plecturocebus oenanthe), of which it is estimated that its population has decreased by 80% in the last 25 years.
  • In Danger (EN) It means that the species faces a very high risk of extinction in the wild. For example: the cactus Discocactus ferricolawhich lives in only three places and its population has decreased by 30% over the last 30 years.
  • Vulnerable (VU) It means that the species faces a high but not immediate risk of extinction in the wild. For example: the Monterey cypress (Cupressus macrocarpa) has a very fragmented and declining population.
  • Near Threatened (NT) It means that the species does not meet the requirements to be at risk of extinction, but could be in the near future. For example: pudú (Pudu puda), whose population of almost 10,000 individuals is in decline due to forest loss, predation and the introduction of species.
  • Least Concern (LC) It means that the species is not at risk of apparent extinction, given that its numbers are stable or even growing. For example: the white frog (Boana crepitans).
  • Data deficient (DD). It means that there is not enough data on the distribution or condition of the population to catalog the species. Therefore, more studies are required to know if it is threatened or not.
  • Not evaluated (NE) It means that the species has not yet been classified according to the IUCN evaluation criteria.

Each country can draw up its own list of species, with its own categories. For example, the United States classifies those that may become extinct throughout all or much of their range as “endangered species,” and those that may become extinct in the near future as “threatened species.”

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On the other hand, in Mexico four categories are used for species at risk. These are:

  • Probably extinct in the wild (E) It means that the native species has disappeared in the national territory, but it is known that there are specimens in confinement or outside of Mexico. For example: the imperial woodpecker and the San Quentin kangaroo rat.
  • In danger of extinction (P). It means that the range or population size of a species has been severely reduced, putting its genetic variability and therefore its survival at risk. It matches the IUCN CR and EN categories. For example: the Guatemalan fir and the black howler monkey.
  • Threatened (A) It means that the species may be in danger of extinction in the short or medium term due to the reduction of its population or the deterioration of its habitat. It matches the IUCN VU category. For example: the Yucatecan parrot and the mazayel mushroom.
  • Subject to special protection (PR) It means that the species could become threatened by factors that harm its viability, so it is necessary to promote its recovery and conservation. It matches the IUCN least risk categories. For example: the Las Marías cinnamon hummingbird and the Sonoran green toad.

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References

  • World Wildlife Fund. (sf). What does “endangered species” mean? WorldWildLife
  • World Wildlife Fund. (March 21, 2022). What is the sixth mass extinction and what can we do about it? WorldWildLife
  • Rodríguez, H. (March 13, 2023). Animals in danger of extinction. National Geographic Spain. National Geographic
  • Jane Goodall Argentina Institute. (January 16, 2018). What is the point of saving endangered species? Jane Goodall
  • Mexican Biodiversity. (July 21, 2022). Risk categories in Mexico. National Commission for the Knowledge and Use of Biodiversity. Biodiversity
  • Aquae Foundation. (September 23, 2021). 10 species in danger of extinction. FoundationAquae
  • The National Wildlife Federation. (sf). Endangered species. NWF
  • Animal Welfare Institute. (sf). List of endangered species. Retrieved April 13, 2023 from AWIonline
  • International Union for Conservation of Nature. (2022). The IUCN Red List of Threatened Species. Version 2022-2. IUCNredlist
  • “Endangered species” on Wikipedia.
  • “Animals in danger of extinction” in Natural Geographic.
  • “Endangered species” in The National Wildlife Federation.
  • “Endangered species” on Animal Planet.
  • “List of endangered species” in Animal Welfare Institute.

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