Efforts to save endangered species may, paradoxically, lead to conservation-induced extinction of other species. This mostly threatens the parasite and pathogen species that are highly host-specific to critically endangered hosts. When the last individuals of a host species are captured for the purpose of captive breeding and reintroduction programs, they typically undergo anti-parasitic treatments to increase survival and reproductive success. This practice may unintentionally result in the extinction of the species antagonistic to the target species, such as certain parasites. It has been proposed that the parasites should be reintroduced to the endangered population. A few cases of conservation-induced extinction have occurred in parasitic
lice
Louse ( : lice) is the common name for any member of the clade Phthiraptera, which contains nearly 5,000 species of wingless parasitic insects. Phthiraptera has variously been recognized as an order, infraorder, or a parvorder, as a result o ...
.
Examples
* Parasite: ''
Colpocephalum californici
''Colpocephalum californici'', the California condor louse, was a species of chewing louse which parasitized the critically endangered California condor. It became extinct when the remaining California condors were deloused and treated with pesti ...
'' – host:
California condor
The California condor (''Gymnogyps californianus'') is a New World vulture and the largest North American land bird. It became extinct in the wild in 1987 when all remaining wild individuals were captured, but has since been reintroduced to nor ...
[Dunn RR 2009. Coextinction: anecdotes, models, and speculation. In Holocene Extinctions (ed. S.T. Turvey), pp. 167–180. Oxford University Press, Oxford, UK.]The parasite most probably became extinct when the last individuals of its only host species were captured for a captive-breeding program; all parasites found were deliberately killed in an attempt to assist the host's survival.
* Parasite: ''
Rallicola pilgrimi'' – host:
little spotted kiwi
The little spotted kiwi or little grey kiwi (''Apteryx owenii'') is a small flightless bird in the kiwi family Apterygidae. It is the smallest species of all five kiwis, at about , about the size of a bantam. It is endemic to New Zealand, and in ...
[Buckley TR, Palma RL, Johns PM, Gleeson DM, Heath ACG, Hitchmough RA, Stringer IAN 2012. The conservation status of small or less well known groups of New Zealand terrestrial invertebrates. ''New Zealand Entomologist'' 35: 137–143.]The parasite most probably became extinct when the last individuals of its only host species were captured and, after routine veterinary antiparasitic treatments, re-introduced into predator-free islands.
* Parasite: ''
Rallicola guami
''Rallicola'' is a genus of chewing louse. It is an ectoparasite of rails and other birds. It was named by Thomas Harvey Johnston and Launcelot Harrison in 1911. There are two subgenera aside from the nominotypical subgenus: ''Aptericola'', whos ...
'' – host:
Guam rail
The Guam rail (''Hypotaenidia owstoni'') is a species of flightless bird, endemic to the United States territory of Guam, where it is known locally as the ''Ko'ko bird. The Guam rail disappeared from southern Guam in the early 1970s and was exti ...
The only known host species of this parasite exists exclusively in captivity and kept under veterinary control. No information about the fate of the parasite, likely extinct.
* Parasite: ''
Linognathus petasmatus'' – host:
scimitar-horned oryx
The scimitar oryx (''Oryx dammah''), also known as the scimitar-horned oryx and the Sahara oryx, is a ''Oryx'' species that was once widespread across North Africa. In 2000, it was declared extinct in the wild on the IUCN Red List.
A captive bre ...
The host specificity of this parasite is uncertain. Either it was specific to the scimitar-horned oryx and became extinct during captive breeding of the host, or – alternatively – it may be specific to the
addax
The addax (''Addax nasomaculatus''), also known as the white antelope and the screwhorn antelope, is an antelope native to the Sahara Desert. The only member of the genus ''Addax'', it was first described scientifically by Henri de Blainvil ...
and possibly still surviving in the wild.
*Parasite: ''
Felicola isidoroi
''Felicola isidoroi'', the Iberian lynx louse, was a species of trichodectid chewing louse. It was known only from a single specimen, a male, and likely died out when the last survivors of its host species, the Iberian lynx, were taken into capt ...
'' – host:
Iberian lynx
The Iberian lynx (''Lynx pardinus'') is a wild cat species endemic to the Iberian Peninsula in southwestern Europe. It is listed as Endangered on the IUCN Red List. In the 20th century, the Iberian lynx population had declined because of overhun ...
.
[Pérez, J.M.; Sánchez, I. & Palma, R.L. (2013). The dilemma of conserving parasites: the case of ''Felicola (Lorisicola) isidoroi'' (Phthiraptera: Trichodectidae) and its host, the endangered Iberian lynx (''Lynx pardinus''). ''Insect Conservation and Diversity'' 6: 680–686.]As with ''Colpocephalum californici'', likely became extinct when the last individuals of its host species were taken into captivity and deloused.
Erroneous example
* The
trichodectid louse of the
black-footed ferret
The black-footed ferret (''Mustela nigripes''), also known as the American polecatHeptner, V. G. (Vladimir Georgievich); Nasimovich, A. A; Bannikov, Andrei Grigorovich; Hoffmann, Robert S. (2001)''Mammals of the Soviet Union''Volume: v. 2, pt. 1 ...
has been mentioned in the literature several times
[Gompper ME, Williams ES 1998. Parasite conservation and the black-footed ferret recovery program. '']Conservation Biology
Conservation biology is the study of the conservation of nature and of Earth's biodiversity with the aim of protecting species, their habitats, and ecosystems from excessive rates of extinction and the erosion of biotic interactions. It is an int ...
'' 12: 730–732. as a parasite that became extinct during the captive breeding program of the host. However, this parasite most probably never existed as a separate species from ''
Neotrichodectes minutus''.
See also
*
Cobra effect
A perverse incentive is an incentive that has an unintended and undesirable result that is contrary to the intentions of its designers. The cobra effect is the most direct kind of perverse incentive, typically because the incentive unintentionall ...
, the general phenomenon of a solution to a problem making the problem worse
*
Conservation biology of parasites
A large proportion of living species on Earth live a parasitic way of life. Parasites have traditionally been seen as targets of eradication efforts, and they have often been overlooked in conservation efforts. In the case of parasites living in t ...
References
External links
The Iberian lynx and its unique louse
{{Extinction
Conservation biology
Extinction
Neologisms