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The northern crested newt, great crested newt or warty newt (''Triturus cristatus'') is a
newt A newt is a salamander in the subfamily Pleurodelinae. The terrestrial juvenile phase is called an eft. Unlike other members of the family Salamandridae, newts are semiaquatic, alternating between aquatic and terrestrial habitats. Not all aqua ...
species native to
Great Britain Great Britain is an island in the North Atlantic Ocean off the northwest coast of continental Europe. With an area of , it is the largest of the British Isles, the largest European island and the ninth-largest island in the world. It is ...
, northern and central continental Europe and parts of
Western Siberia Western Siberia or West Siberia (russian: Западная Сибирь, Zapadnaya Sibir'; kk, Батыс Сібір) is a part of the larger region of Siberia that is mostly located in the Russian Federation. It lies between the Ural region a ...
. It is a large newt, with females growing up to long. Its back and sides are dark brown, while the belly is yellow to orange with dark blotches. Males develop a conspicuous jagged crest on their back and tail during the breeding season. The northern crested newt spends most of the year on land, mainly in forested areas in lowlands. It moves to aquatic breeding sites, mainly larger fish-free
pond A pond is an area filled with water, either natural or Artificiality, artificial, that is smaller than a lake. Defining them to be less than in area, less than deep, and with less than 30% Aquatic plant, emergent vegetation helps in disting ...
s, in spring. Males court females with a ritualised
display Display may refer to: Technology * Display device, output device for presenting information, including: ** Cathode ray tube, video display that provides a quality picture, but can be very heavy and deep ** Electronic visual display, output dev ...
and deposit a
spermatophore A spermatophore or sperm ampulla is a capsule or mass containing spermatozoa created by males of various animal species, especially salamanders and arthropods, and transferred in entirety to the female's ovipore during reproduction. Spermatophores ...
on the ground, which the female then picks up with her
cloaca In animal anatomy, a cloaca ( ), plural cloacae ( or ), is the posterior orifice that serves as the only opening for the digestive, reproductive, and urinary tracts (if present) of many vertebrate animals. All amphibians, reptiles and birds ...
. After fertilisation, a female lays around 200 eggs, folding them into water plants. The
larvae A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. T ...
develop over two to four months before metamorphosing into terrestrial juveniles (
eft A newt is a salamander in the subfamily Pleurodelinae. The terrestrial juvenile phase is called an eft. Unlike other members of the family Salamandridae, newts are semiaquatic, alternating between aquatic and terrestrial habitats. Not all aquat ...
s). Both larvae and land-dwelling newts mainly feed on different
invertebrates Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...
. Several of the northern crested newt's former subspecies are now recognised as separate species in the genus ''
Triturus ''Triturus'' is a genus of newts comprising the crested and the marbled newts, which are found from Great Britain through most of continental Europe to westernmost Siberia, Anatolia, and the Caspian Sea region. Their English names refer to thei ...
''. Its closest relative is the Danube crested newt (''T. dobrogicus''). It sometimes forms hybrids with some of its relatives, including the marbled newt (''T. marmoratus''). Although today the most widespread ''Triturus'' species, the northern crested newt was probably confined to small refugial areas in the
Carpathians The Carpathian Mountains or Carpathians () are a range of mountains forming an arc across Central Europe. Roughly long, it is the third-longest European mountain range after the Ural Mountains, Urals at and the Scandinavian Mountains at . The ...
during the
Last Glacial Maximum The Last Glacial Maximum (LGM), also referred to as the Late Glacial Maximum, was the most recent time during the Last Glacial Period that ice sheets were at their greatest extent. Ice sheets covered much of Northern North America, Northern Eu ...
. While the
International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natur ...
lists it as
Least Concern A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. Th ...
species, populations of the northern crested newt have been declining. The main threat is
habitat destruction Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby ...
, for example, through
urban sprawl Urban sprawl (also known as suburban sprawl or urban encroachment) is defined as "the spreading of urban developments (such as houses and shopping centers) on undeveloped land near a city." Urban sprawl has been described as the unrestricted growt ...
. The species is listed as a European Protected Species.


Taxonomy

The northern crested newt was described as ''Triton cristatus'' by
Josephus Nicolaus Laurenti Josephus Nicolaus Laurenti (4 December 1735, Vienna – 17 February 1805, Vienna) was an Austrian naturalist and zoologist of Italian origin. Laurenti is considered the auctor of the class Reptilia ( reptiles) through his authorship of ' (176 ...
in 1768. As
Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, t ...
had already used the name ''Triton'' for a genus of sea snails ten years before,
Constantine Samuel Rafinesque Constantine Samuel Rafinesque-Schmaltz (; October 22, 1783September 18, 1840) was a French 19th-century polymath born near Constantinople in the Ottoman Empire and self-educated in France. He traveled as a young man in the United States, ultima ...
introduced the new genus name ''Triturus'' in 1815, with ''T. cristatus'' as
type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen( ...
. Over 40 scientific names introduced over time are now considered as
synonyms A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are ...
, including ''Lacertus aquatilis'', a ''
nomen oblitum In zoological nomenclature, a ''nomen oblitum'' (plural: ''nomina oblita''; Latin for "forgotten name") is a disused scientific name which has been declared to be obsolete (figuratively 'forgotten') in favour of another 'protected' name. In its p ...
'' published four years before Laurenti's species name. Hybrids resulting from the cross of a crested newt male with a marbled newt (''Triturus marmoratus'') female were mistakenly described as distinct species ''Triton blasii'', and the reverse hybrids as ''Triton trouessarti''. ''T. cristatus'' was long considered as a single species, the "crested newt", with several subspecies. Substantial genetic differences between these subspecies were, however, noted and eventually led to their recognition as full species, often collectively referred to as "''T. cristatus''
species complex In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...
". There are now seven accepted species of crested newts, of which the northern crested newt is the most widespread.


Description

The northern crested newt is a relatively large newt species. Males usually reach total length, while females grow up to . Rare individuals of have been recorded. Other crested newt species are more stockily built; only the Danube crested newt (''T. dobrogicus'') is more slender. Body shape is correlated with skeletal build: The northern crested newt has 15 rib-bearing
vertebrae The spinal column, a defining synapomorphy shared by nearly all vertebrates, Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristi ...
, only the Danube crested newt has more (16–17), while the other, more stocky ''Triturus'' species have 14 or less. The newts have rough skin, and are dark brown on the back and sides, with black spots and heavy white stippling on the flanks. The female has a yellow line running along the lower tail edge. The throat is mixed yellow–black with fine white stippling, the belly yellow to orange with dark, irregular blotches. During the aquatic breeding season, males develop crest up to high, which runs along the back and tail but is interrupted at the tail base. It is heavily indented on the back but smoother on the tail. Also during breeding season, the male's
cloaca In animal anatomy, a cloaca ( ), plural cloacae ( or ), is the posterior orifice that serves as the only opening for the digestive, reproductive, and urinary tracts (if present) of many vertebrate animals. All amphibians, reptiles and birds ...
swells and it has a blue–white flash running along the sides of the tail. Females do not develop a crest.


Range

The northern crested newt is the most widespread and northerly crested newt species. The northern edge of its range runs from
Great Britain Great Britain is an island in the North Atlantic Ocean off the northwest coast of continental Europe. With an area of , it is the largest of the British Isles, the largest European island and the ninth-largest island in the world. It is ...
through southern
Fennoscandia __NOTOC__ Fennoscandia ( Finnish, Swedish and no, Fennoskandia, nocat=1; russian: Фенноскандия, Fennoskandiya) or the Fennoscandian Peninsula is the geographical peninsula in Europe, which includes the Scandinavian and Kola penins ...
to the
Republic of Karelia The Republic of Karelia (russian: Респу́блика Каре́лия, Respublika Kareliya; ; krl, Karjalan tašavalta; ; fi, Karjalan tasavalta; vep, Karjalan Tazovaldkund, Ludic: ''Kard’alan tazavald''), also known as just Karelia (ru ...
in
Russia Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-eigh ...
; the southern margin runs through central France, southwest
Romania Romania ( ; ro, România ) is a country located at the crossroads of Central, Eastern, and Southeastern Europe. It borders Bulgaria to the south, Ukraine to the north, Hungary to the west, Serbia to the southwest, Moldova to the east, a ...
,
Moldavia Moldavia ( ro, Moldova, or , literally "The Country of Moldavia"; in Romanian Cyrillic: or ; chu, Землѧ Молдавскаѧ; el, Ἡγεμονία τῆς Μολδαβίας) is a historical region and former principality in Centra ...
and
Ukraine Ukraine ( uk, Україна, Ukraïna, ) is a country in Eastern Europe. It is the second-largest European country after Russia, which it borders to the east and northeast. Ukraine covers approximately . Prior to the ongoing Russian invas ...
, heading from there into central Russia and through the
Ural Mountains The Ural Mountains ( ; rus, Ура́льские го́ры, r=Uralskiye gory, p=ʊˈralʲskʲɪjə ˈɡorɨ; ba, Урал тауҙары) or simply the Urals, are a mountain range that runs approximately from north to south through western ...
. The eastern extent of the great crested newt's range reaches into
Western Siberia Western Siberia or West Siberia (russian: Западная Сибирь, Zapadnaya Sibir'; kk, Батыс Сібір) is a part of the larger region of Siberia that is mostly located in the Russian Federation. It lies between the Ural region a ...
, running from the
Perm Krai Perm Krai (russian: Пе́рмский край, r=Permsky kray, p=ˈpʲɛrmskʲɪj ˈkraj, ''Permsky krai'', , ''Perem lador'') is a federal subject of Russia (a krai) that came into existence on December 1, 2005 as a result of the 2004 re ...
to the
Kurgan Oblast Kurgan Oblast (russian: Курга́нская о́бласть, ''Kurganskaya oblast'') is a federal subject of Russia (an oblast). Its administrative center is the city of Kurgan. In June 2014, the population was estimated to be 874,100,Kurga ...
. In western France, the species co-occurs and sometimes hybridises (see section ''Evolution'' below) with the marbled newt (''Triturus marmoratus''). In southeast Europe, its range borders that of the Italian crested newt (''T. carnifex''), the Danube crested newt (''T. dobrogicus''), the
Macedonian crested newt ''Triturus macedonicus'', the Macedonian crested newt, is a newt species of the crested newt species complex in genus ''Triturus'', found in the Western Balkan peninsula (Bosnia-Herzegovina, Albania, North Macedonia, north-western Greece and sout ...
(''T. macedonicus'') and the Balkan crested newt (''T. ivanbureschi'').


Habitat

Outside of the breeding season, northern crested newts are mainly
forest A forest is an area of land dominated by trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function. The United Nations' ...
-dwellers. They prefer deciduous woodlands or groves, but conifer woods are also accepted, especially in the far northern and southern ranges. In the absence of forests, other cover-rich habitats, as for example
hedgerows A hedge or hedgerow is a line of closely spaced shrubs and sometimes trees, planted and trained to form a barrier or to mark the boundary of an area, such as between neighbouring properties. Hedges that are used to separate a road from adjoini ...
,
scrub Scrub(s) may refer to: * Scrub, low shrub and grass characteristic of scrubland * Scrubs (clothing), worn by medical staff * ''Scrubs'' (TV series), an American television program * Scrubs (occupation), also called "scrub tech," "scrub nurse," ...
, swampy meadows, or
quarries A quarry is a type of open-pit mine in which dimension stone, rock, construction aggregate, riprap, sand, gravel, or slate is excavated from the ground. The operation of quarries is regulated in some jurisdictions to reduce their environ ...
, can be inhabited. Preferred aquatic breeding sites are stagnant, mid- to large-sized, unshaded water bodies with abundant underwater vegetation but without fish (which prey on larvae). Typical examples are larger
ponds A pond is an area filled with water, either natural or artificial, that is smaller than a lake. Defining them to be less than in area, less than deep, and with less than 30% emergent vegetation helps in distinguishing their ecology from tha ...
, which need not be of natural origin; indeed, most ponds inhabited in the United Kingdom are human-made. Examples of other suitable secondary habitats are ditches, channels, gravel pit lakes, or garden ponds. Other newts that can sometimes be found in the same breeding sites are the smooth newt (''Lissotriton vulgaris''), the palmate newt (''L. helveticus''), the
Carpathian newt The Carpathian newt, or Montandon’s newt, (''Lissotriton montandoni'') is a species of salamander in the family Salamandridae found in Czech Republic, Poland, Romania, Slovakia, and Ukraine. The total length of adults of this species is around ...
(''L. montadoni''), the
alpine newt The alpine newt (''Ichthyosaura alpestris'') is a species of newt native to continental Europe and introduced to Great Britain and New Zealand. Adults measure and are usually dark grey to blue on the back and sides, with an orange belly and thro ...
(''Ichthyosaura alpestris'') and the marbled newt (''Triturus marmoratus''). The northern crested newt is generally a lowland species but has been found up to in the
Alps The Alps () ; german: Alpen ; it, Alpi ; rm, Alps ; sl, Alpe . are the highest and most extensive mountain range system that lies entirely in Europe, stretching approximately across seven Alpine countries (from west to east): France, ...
.


Population Structure, Speciation, and Phylogeny


Hybridization

In certain areas of France, the northern crested newt and the marbled newt overlap, and hybrids are present. As the northern crested newt's population grows, and marbled newt population struggles, these hybrids have been shown to possess good qualities of both. They have more fecundity than the two newts however have a hard time keeping their eggs alive.


Life cycle and behaviour

Like other newts, ''T. cristatus'' develops in the water as a larva and returns to the water each year for breeding. Adults spend around seven months of the year on land. After larval development in the first year, juveniles pass another year or two before reaching maturity; in the north and at higher elevations, this can take longer. The larval and juvenile stages are the riskiest for the newts, while survival is higher in adults. Once the risky stages passed, adult newts usually have a lifespan of seven to nine years, although individuals have reached 17 years in the wild. Adult newts begin moving to their breeding sites in spring when temperatures stay above , usually in March. In the aquatic phase, crested newts are mostly nocturnal and, compared to smaller newt species, usually prefer the deeper parts of a water body, where they hide under vegetation. As with other newts, they have to occasionally move to the surface to breathe air. The aquatic phase serves not only for reproduction, but also offers more abundant prey, and immature crested newts frequently return to the water in spring even if they do not breed. During the terrestrial phase, the newts use hiding places such as logs, bark, planks, stone walls, or small mammal burrows; several individuals may occupy such refuges at the same time. Since the newts generally stay very close to their aquatic breeding sites, the quality of the surrounding terrestrial habitat largely determines whether an otherwise suitable water body will be colonised. Great crested newts may also climb vegetation during their terrestrial phase, although the exact function of this behaviour is not known at present. The juvenile
eft A newt is a salamander in the subfamily Pleurodelinae. The terrestrial juvenile phase is called an eft. Unlike other members of the family Salamandridae, newts are semiaquatic, alternating between aquatic and terrestrial habitats. Not all aquat ...
s often disperse to new breeding sites, while the adults in general move back to the same breeding sites each year. The newts do not migrate very far: they may cover around in one night and rarely disperse much farther than . Over most of their range, they
hibernate Hibernation is a state of minimal activity and metabolic depression undergone by some animal species. Hibernation is a seasonal heterothermy characterized by low body-temperature, slow breathing and heart-rate, and low metabolic rate. It most ...
in winter, using mainly subterranean hiding places, where many individuals will often congregate.


Diet and predators

Northern crested newts feed mainly on invertebrates. During the land phase, prey include
earthworm An earthworm is a terrestrial invertebrate that belongs to the phylum Annelida. They exhibit a tube-within-a-tube body plan; they are externally segmented with corresponding internal segmentation; and they usually have setae on all segments. ...
s and other
annelids The annelids (Annelida , from Latin ', "little ring"), also known as the segmented worms, are a large phylum, with over 22,000 extant species including ragworms, earthworms, and leeches. The species exist in and have adapted to various ecolo ...
, different
insects Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs ...
,
woodlice A woodlouse (plural woodlice) is an isopod crustacean from the polyphyleticThe current consensus is that Oniscidea is actually triphyletic suborder Oniscidea within the order Isopoda. They get their name from often being found in old wood. ...
, and
snails and slugs The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. Ther ...
. During the breeding season, they prey on various aquatic invertebrates, and also
tadpoles A tadpole is the larval stage in the biological life cycle of an amphibian. Most tadpoles are fully aquatic, though some species of amphibians have tadpoles that are terrestrial. Tadpoles have some fish-like features that may not be found ...
of other amphibians such as the
common frog The common frog or grass frog (''Rana temporaria''), also known as the European common frog, European common brown frog, European grass frog, European Holarctic true frog, European pond frog or European brown frog, is a semi-aquatic amphibian ...
or
common toad The common toad, European toad, or in Anglophone parts of Europe, simply the toad (''Bufo bufo'', from Latin ''bufo'' "toad"), is a frog found throughout most of Europe (with the exception of Ireland, Iceland, and some Mediterranean islands), in ...
, and smaller newts. Larvae, depending on their size, eat small invertebrates and tadpoles, and also smaller larvae of their own species. The larvae are themselves eaten by various animals such as carnivorous invertebrates and water birds, and are especially vulnerable to predatory fish. Adults generally avoid predators through their hidden lifestyle but are sometimes eaten by
herons The herons are long-legged, long-necked, freshwater and coastal birds in the family Ardeidae, with 72 recognised species, some of which are referred to as egrets or bitterns rather than herons. Members of the genera ''Botaurus'' and ''Ixobrychu ...
and other birds, snakes such as the
grass snake The grass snake (''Natrix natrix''), sometimes called the ringed snake or water snake, is a Eurasian non- venomous colubrid snake. It is often found near water and feeds almost exclusively on amphibians. Subspecies Many subspecies are recogn ...
, and mammals such as
shrew Shrews (family Soricidae) are small mole-like mammals classified in the order Eulipotyphla. True shrews are not to be confused with treeshrews, otter shrews, elephant shrews, West Indies shrews, or marsupial shrews, which belong to diffe ...
s,
badgers Badgers are short-legged omnivores in the family Mustelidae (which also includes the otters, wolverines, martens, minks, polecats, weasels, and ferrets). Badgers are a polyphyletic rather than a natural taxonomic grouping, being united by th ...
and hedgehogs. They secrete the poison
tetrodotoxin Tetrodotoxin (TTX) is a potent neurotoxin. Its name derives from Tetraodontiformes, an order that includes pufferfish, porcupinefish, ocean sunfish, and triggerfish; several of these species carry the toxin. Although tetrodotoxin was discove ...
from their skin, albeit much less than for example the North American Pacific newts (''Taricha''). The bright yellow or orange underside of crested newts is a
warning coloration Aposematism is the Advertising in biology, advertising by an animal to potential predation, predators that it is not worth attacking or eating. This unprofitability may consist of any defences which make the prey difficult to kill and eat, suc ...
which can be presented in case of perceived danger. In such a posture, the newts typically roll up and secrete a milky substance.


Courtship and reproduction

Northern crested newts, like their relatives in the genus ''Triturus'', perform a complex
courtship display A courtship display is a set of display behaviors in which an animal, usually a male, attempts to attract a mate; the mate exercises choice, so sexual selection acts on the display. These behaviors often include ritualized movement ("dances"), v ...
, where the male attracts a female through specific body movements and waves
pheromones A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavi ...
to her. The males are territorial and use small patches of clear ground as leks, or courtship arenas. When successful, they guide the female over a
spermatophore A spermatophore or sperm ampulla is a capsule or mass containing spermatozoa created by males of various animal species, especially salamanders and arthropods, and transferred in entirety to the female's ovipore during reproduction. Spermatophores ...
they deposit on the ground, which she then takes up with her
cloaca In animal anatomy, a cloaca ( ), plural cloacae ( or ), is the posterior orifice that serves as the only opening for the digestive, reproductive, and urinary tracts (if present) of many vertebrate animals. All amphibians, reptiles and birds ...
. The eggs are fertilised internally, and the female deposits them individually, usually folding them into leaves of aquatic plants. A female takes around five minutes for the deposition of one egg. They usually lay around 200 eggs per season. Embryos are usually light-coloured, 1.8–2 mm in diameter with a 6 mm jelly capsule, which distinguishes them from eggs of other co-existing newt species that are smaller and darker-coloured. A genetic particularity shared with other ''Triturus'' species causes 50% of the embryos to die. Larvae hatch after two to five weeks, depending on temperature. As in all salamanders and newts, forelimbs develop first, followed later by the back legs. Unlike smaller newts, crested newt larvae are mostly nektonic, swimming freely in the water column. Just before the transition to land, the larvae resorb their external gills; they can at this stage reach a size of . Metamorphosis into terrestrial
eft A newt is a salamander in the subfamily Pleurodelinae. The terrestrial juvenile phase is called an eft. Unlike other members of the family Salamandridae, newts are semiaquatic, alternating between aquatic and terrestrial habitats. Not all aquat ...
s takes place two to four months after hatching, again depending on temperature. Survival of larvae from hatching to metamorphosis has been estimated at a mean of roughly 4%. In unfavourable conditions, larvae may delay their development and overwinter in water, although this seems to be less common than in the small-bodied newts.


Evolution

The northern crested newt sometimes hybridises with other crested newt species where their ranges meet, but overall, the different species are reproductively isolated. In a case study in the Netherlands, genes of the introduced Italian crested newt (''T. carnifex'') were found to introgress into the
gene pool The gene pool is the set of all genes, or genetic information, in any population, usually of a particular species. Description A large gene pool indicates extensive genetic diversity, which is associated with robust populations that can surv ...
of the native northern crested newt. The closest relative of the northern crested newt, according to
molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...
analyses, is the Danube crested newt (''T. dobrogicus''). In western France, the northern crested newt's range overlaps with that of the marbled newt (''T. marmoratus''), but the two species in general prefer different habitats. When they do occur in the same breeding ponds, they can form hybrids, which have intermediate characteristics. Hybrids resulting from the cross of a crested newt male with a marbled newt female are much rarer due to increased mortality of the larvae and consist only of males. In the reverse cross, males have lower survival rates than females. Overall, viability is reduced in these hybrids and they rarely
backcross Backcrossing is a crossing of a hybrid with one of its parents or an individual genetically similar to its parent, to achieve offspring with a genetic identity closer to that of the parent. It is used in horticulture, animal breeding, and produ ...
with their parent species. Hybrids made up 3–7% of the adult populations in different studies. Little
genetic variation Genetic variation is the difference in DNA among individuals or the differences between populations. The multiple sources of genetic variation include mutation and genetic recombination. Mutations are the ultimate sources of genetic variation, b ...
was found over most of the species' range, except in the
Carpathians The Carpathian Mountains or Carpathians () are a range of mountains forming an arc across Central Europe. Roughly long, it is the third-longest European mountain range after the Ural Mountains, Urals at and the Scandinavian Mountains at . The ...
. This suggests that the Carpathians was a refugium during the
Last Glacial Maximum The Last Glacial Maximum (LGM), also referred to as the Late Glacial Maximum, was the most recent time during the Last Glacial Period that ice sheets were at their greatest extent. Ice sheets covered much of Northern North America, Northern Eu ...
. The northern crested newt then expanded its range north-, east- and westwards when the climate rewarmed.


Threats and conservation

The northern crested newt is listed as species of
Least Concern A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. Th ...
on the
IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biol ...
, but populations are declining. It is rare in some parts of its range and listed in several national red lists. The major reason for decline is
habitat destruction Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby ...
through urban and agricultural development, affecting the aquatic breeding sites as well as the land habitats. Their limited dispersal makes the newts especially vulnerable to
fragmentation Fragmentation or fragmented may refer to: Computers * Fragmentation (computing), a phenomenon of computer storage * File system fragmentation, the tendency of a file system to lay out the contents of files non-continuously * Fragmented distributi ...
, i.e. the loss of connections for exchange between suitable habitats. Other threats include the introduction of fish and crayfish into breeding ponds, collection for the pet trade in its eastern range, warmer and wetter winters due to
global warming In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate variability and change, Climate change in a broader sense also includes ...
,
genetic pollution Genetic pollution is a controversial term for uncontrolled gene flow In population genetics, gene flow (also known as gene migration or geneflow and allele flow) is the transfer of genetic material from one population to another. If the ra ...
through hybridisation with other, introduced crested newt species, the use of
road salt Sodium chloride , commonly known as salt (although sea salt also contains other chemical salts), is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. With molar masses of 22.99 and 35.45 g/ ...
, and potentially the pathogenic fungus '' Batrachochytrium salamandrivorans''. The northern crested newt is listed in
Berne Convention The Berne Convention for the Protection of Literary and Artistic Works, usually known as the Berne Convention, was an international assembly held in 1886 in the Swiss city of Bern by ten European countries with the goal to agree on a set of le ...
Appendix II as "strictly protected". It is also included in Annex II (species requiring designation of special areas of conservation) and IV (species in need of strict protection) of the EU habitats and species directive, as a European Protected Species. As required by these frameworks, its capture, disturbance, killing or trade, as well as the destruction of its habitats, are prohibited in most European countries. The EU habitats directive is also the basis for the
Natura 2000 Natura 2000 is a network of nature protection areas in the territory of the European Union. It is made up of Special Areas of Conservation and Special Protection Areas designated under the Habitats Directive and the Birds Directive, respectiv ...
protected areas, several of which have been designated specifically to protect the northern crested newt. Preservation of natural water bodies, reduction of fertiliser and pesticide use, control or eradication of introduced predatory fish, and the connection of habitats through sufficiently wide corridors of uncultivated land are seen as effective conservation actions. A network of aquatic habitats in proximity is important to sustain populations, and the creation of new breeding ponds is in general very effective as they are rapidly colonised when other habitats are nearby. In some cases, entire populations have been moved when threatened by development projects, but such translocations need to be carefully planned to be successful. Strict protection of the northern crested newt in the United Kingdom has created conflicts with local development projects, but the species is also seen as a
flagship species In conservation biology, a flagship species is a species chosen to raise support for biodiversity conservation in a given place or social context. Definitions have varied, but they have tended to focus on the strategic goals and the socio-economi ...
, whose conservation also benefits a range of other amphibians. Government agencies have issued specific guidelines for the mitigation of development impacts.


References

{{Taxonbar, from=Q138539 Triturus Amphibians of Europe Fauna of the United Kingdom Amphibians described in 1768 Taxa named by Josephus Nicolaus Laurenti Articles containing video clips