Coextinction
Encyclopedia
Coextinction of a species
is the loss of a species as a consequence of the extinction
of another. The term was originally used in the context of the extinction of parasitic insects following the loss of their specific hosts. The term is now used to describe the subsequent loss of any interacting
species, including predators with their prey, and specialist herbivore
s with their food source. Coextinction is especially common when a keystone species
goes extinct.
The most often cited example is that of the extinct passenger pigeon
and its parasitic bird lice
Columbicola extinctus and Campanulotes defectus. Recently, C. extinctus was rediscovered on the band-tailed pigeon
, and C. defectus was found to be a likely case of misidentification of the existing Campanulotes flavus. However, even though the passenger pigeon lice story has a happy ending (i.e. rediscovery), coextinctions of other parasites, even on the passenger pigeon, may have occurred. Several louse species—such as Rallicola extinctus
, a huia
parasite - probably became extinct together with their hosts.
In a 2004 paper in Science
, ecologist
Lian Pin Koh and colleagues discuss coextinction, stating
Koh et al. also define coendangered as taxon
One example is the near extinction of the genus Hibiscadelphus
as a consequence of the disappearance of several of the Hawaiian honeycreeper
s, its pollinator
s. There are several instances of predators and scavengers dying out following the disappearance of species which represented their source of food: for example, the coextinction of the Haast's Eagle
with the moa
.
Coextinction may also occur on a local level: for example, the decline in the red ant Myrmica sabuleti
in southern England
, caused by habitat loss, resulted in the local extinction of the Large Blue butterfly, which is dependent on the ant as a host for the larvae. In this case the ant avoided local extinction, and the butterfly has been reintroduced.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
is the loss of a species as a consequence of the extinction
Extinction
In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...
of another. The term was originally used in the context of the extinction of parasitic insects following the loss of their specific hosts. The term is now used to describe the subsequent loss of any interacting
Biological interaction
Biological interactions are the effects organisms in a community have on one another. In the natural world no organism exists in absolute isolation, and thus every organism must interact with the environment and other organisms...
species, including predators with their prey, and specialist herbivore
Herbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...
s with their food source. Coextinction is especially common when a keystone species
Keystone species
A keystone species is a species that has a disproportionately large effect on its environment relative to its abundance. Such species play a critical role in maintaining the structure of an ecological community, affecting many other organisms in an ecosystem and helping to determine the types and...
goes extinct.
The most often cited example is that of the extinct passenger pigeon
Passenger Pigeon
The Passenger Pigeon or Wild Pigeon was a bird, now extinct, that existed in North America and lived in enormous migratory flocks until the early 20th century...
and its parasitic bird lice
Bird louse
Bird louse refers to any chewing louse of order Phthiraptera which parasitizes warm-blooded animals, especially birds. Bird lice may feed on feathers, skin, or blood. They have no wings, and ther biting mouth parts distinguish them from true lice, which suck blood.Almost all domestic birds are...
Columbicola extinctus and Campanulotes defectus. Recently, C. extinctus was rediscovered on the band-tailed pigeon
Band-tailed Pigeon
The Band-tailed Pigeon, Patagioenas fasciata, is a medium-sized bird of the Americas. Its closest relatives are the Chilean Pigeon and the Ring-tailed Pigeon, which form a clade of Patagioenas with a terminal tail band and iridescent plumage on their necks.It ranges from British Columbia, Utah, and...
, and C. defectus was found to be a likely case of misidentification of the existing Campanulotes flavus. However, even though the passenger pigeon lice story has a happy ending (i.e. rediscovery), coextinctions of other parasites, even on the passenger pigeon, may have occurred. Several louse species—such as Rallicola extinctus
Rallicola extinctus
Rallicola extinctus is an extinct species of phtilopterid louse. This parasite was only known to live on the now extinct Huia and is thought to have become extinct with its host. It was initially placed in its own separate genus, Huiacola, which means "Huia inhabitant". It was endemic to New...
, a huia
Huia
The Huia was the largest species of New Zealand wattlebird and was endemic to the North Island of New Zealand. Its extinction in the early 20th century had two primary causes. The first was rampant overhunting to procure Huia skins for mounted specimens, which were in worldwide demand by...
parasite - probably became extinct together with their hosts.
In a 2004 paper in Science
Science (journal)
Science is the academic journal of the American Association for the Advancement of Science and is one of the world's top scientific journals....
, ecologist
Ecology
Ecology is the scientific study of the relations that living organisms have with respect to each other and their natural environment. Variables of interest to ecologists include the composition, distribution, amount , number, and changing states of organisms within and among ecosystems...
Lian Pin Koh and colleagues discuss coextinction, stating
"Species coextinction is a manifestation of the interconnectedness of organisms in complex ecosystemEcosystemAn ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....
s. The loss of species through coextinction represents the loss of irreplaceable evolutionEvolutionEvolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
ary and coevolutionary history. In view of the global extinction crisis, it is imperative that coextinction be the focus of future research to understand the intricate processes of species extinctions. While coextinction may not be the most important cause of species extinctions, it is certainly an insidious one." (Koh et al. 2004)
Koh et al. also define coendangered as taxon
Taxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...
"likely to go extinct if their currently endangered hosts [...] become extinct."
One example is the near extinction of the genus Hibiscadelphus
Hibiscadelphus
Hibiscadelphus is a genus of Malvaceae from the subfamily Malvoideae endemic to Hawaii. It was known by the Native Hawaiians as hau kuahiwi which means "mountain Hibiscus". The Latin name means "brother of Hibiscus"...
as a consequence of the disappearance of several of the Hawaiian honeycreeper
Hawaiian honeycreeper
Hawaiian honeycreepers are small, passerine birds endemic to Hawaii. Some authorities still categorize this group as a family Drepanididae, but in recent years, most authorities consider them a subfamily, Drepanidinae, of Fringillidae, the finch family...
s, its pollinator
Pollinator
A pollinator is the biotic agent that moves pollen from the male anthers of a flower to the female stigma of a flower to accomplish fertilization or syngamy of the female gamete in the ovule of the flower by the male gamete from the pollen grain...
s. There are several instances of predators and scavengers dying out following the disappearance of species which represented their source of food: for example, the coextinction of the Haast's Eagle
Haast's Eagle
Haast's Eagle was a species of massive eagles that once lived on the South Island of New Zealand. The species was the largest eagle known to have existed. Its prey consisted mainly of gigantic flightless birds that were unable to defend themselves from the striking force and speed of these eagles,...
with the moa
Moa
The moa were eleven species of flightless birds endemic to New Zealand. The two largest species, Dinornis robustus and Dinornis novaezelandiae, reached about in height with neck outstretched, and weighed about ....
.
Coextinction may also occur on a local level: for example, the decline in the red ant Myrmica sabuleti
Myrmica sabuleti
Myrmica sabuleti is a species of ant. The species is indigenous to Europe and most colonies are polygynous. The Large Blue butterfly caterpillar parasitically prey on the species as it hatchess on thyme buds and then tricks the ants into believing it is one of their own larvae, ants then carry it...
in southern England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
, caused by habitat loss, resulted in the local extinction of the Large Blue butterfly, which is dependent on the ant as a host for the larvae. In this case the ant avoided local extinction, and the butterfly has been reintroduced.
See also
- DodoDodoThe dodo was a flightless bird endemic to the Indian Ocean island of Mauritius. Related to pigeons and doves, it stood about a meter tall, weighing about , living on fruit, and nesting on the ground....
and TambalacoqueTambalacoqueTambalacoque , also called the Dodo Tree, is a long-lived tree in the family Sapotaceae, endemic to Mauritius. The Dodo Tree is valued for its timber....
, for a supposed case of near-coextinction that turned out to be much more complex