Northern crested newt
| Northern crested newt | ||||||||||||
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Northern crested newt ( Triturus cristatus ) |
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| Triturus cristatus | ||||||||||||
| ( Laurenti , 1768) |
The northern crested newt ( Triturus cristatus ) - in the German-speaking world it is usually simply referred to as crested newt - is a species of amphibian belonging to the tail amphibian order . Within the genus Triturus , this species, together with five others, previously treated as subspecies, forms the super-species of crested newts .
features
The northern crested newt is a fairly large, powerful newt with a broad head. The males reach a length of ten to a maximum of 18 centimeters, the females from eleven to a maximum of 20 centimeters. The upper side is gray-black in color, with indistinct darker points or spots; the skin appears slightly granular warty. The flanks are intensely whitish granulated in the transition to the ventral side. The belly is yellow or orange with black spots. This pattern of spots even enables individual differentiation of the animals in field biological studies. During the mating season, the males develop a high, strongly serrated skin crest on the back and tail, which is interrupted at the tail root (in contrast to the pond newt ). Characteristic of the males is also a mother-of-pearl-silvery band ("milk stripes") on the tail sides and a more domed, black cloaca . The females only have a low caudal fin border. With them, the orange color of the abdomen continues over the cloaca on the lower edge of the tail. Completely black crested newts are also said to occur in Northern Europe. After staying in the water, in late summer the water habit, especially the conspicuous skin fringes of the males, is largely regressed and gives way to a more inconspicuous land dress.
Reproduction and Individual Development
The adult animals migrate from their mostly terrestrial winter quarters to the breeding waters at night when frost-free weather begins . However, subadult specimens in particular also overwinter in bodies of water. The spawning season in Central Europe is concentrated in April and May. Large spawning societies in optimal habitats comprise several hundred adult individuals. The courtship ritual takes place as follows (quotation from Nöllert & Nöllert 1992; omissions or insertions in brackets):
- The male swims in front of the partner and leans his body in an arc against the head region of the female. It makes a slight "cat hump" and moves its tail in waves. Then it reinforces the hunchback position until it is almost in a handstand in front of the partner. It flaps its tail strongly in the direction of the female (also fanning out pheromones ) and touches its head and flank region. If the female responds to the advertisement, she moves towards her partner, who then turns 90 degrees, lifts her tail and presents the opened cesspool to the female . The male gradually moves away from the female, who follows him and finally touches the lower edge of the tail with the tip of the snout. In response to this signal, the male releases the spermatophore (sperm packet), but “marches” on until the cloacal region of the female is roughly above the spermatophore. Then the male stops moving forward by standing across in front of the female. (...) The female is repeatedly pushed back by him through body thrusts or light tail strokes in order to increase the probability of sperm ingestion (through the female's cesspool). (...)
The males occupy certain courtship areas, which they defend against invading other males with threatening gestures.
A female lays several hundred (mostly 200–350) eggs; These are placed individually with the help of the hind legs in leaves of aquatic plants that have been folded into "bags". The flood plumes ( Glyceria fluitans ) that occur in many ponds play an important role . Due to their yellowish color and larger diameter (about two millimeters), they can be easily distinguished from other newt eggs. The embryonic lasts depending on the water temperature and pH of the water five to 30, in average about 15 days.
Larvae
The larvae grow from ten millimeters to eight centimeters in size during their four-month development period. They differ from other newt larvae in their greater body length, 15–16 visible rib furrows, their long limbs and a tail that is darkly spotted at the edge, broadly lined and very long, pointed. They also swim more in open water ( nectic or pelagic behavior), while mountain newt larvae , for example, live more on the bottom of the water ( benthic behavior). As is customary with newts, the front limbs appear first, then the rear ones later - with the frog tadpoles it is the other way round. Sometimes larvae that developed late also overwinter in the water. Occasionally neoteny (or pedomorphism) also occurs: these larvae do not metamorphose at all ; they retain their larval characteristics, for example the outer gill tufts, and still become sexually mature. They stay in the water their whole life.
Young animals
Normal young animals that go ashore need two to three years before they are sexually mature and take part in the reproductive process themselves. But sometimes they take part in the spring hikes to the waters beforehand.
Occurrence
distribution
The northern crested newt is widespread from western France and the British Isles across Central Europe and southern Scandinavia to western Russia . In Germany there is an almost widespread distribution - there are only larger gaps in the extreme northwest ( East Friesland , coastal marshes ), in areas used for intensive agriculture and poorly landscaped areas, in some low mountain ranges and in the high mountain areas. In Switzerland and Austria , the occurrences are also mostly limited to lower elevations north of the main Alpine ridge. Large areas in both countries are not populated by this species, as this is where the southern limit of distribution runs. In the area around Vienna and to the east of it, the Danube crested newt is the typical crested newt, in other parts of the country it is more the Alpine crested newt . Triturus cristatus is mentioned in detail for the states of Vorarlberg , Salzburg , Lower Austria and Upper Austria (there isolated species records up to 1750 m above sea level ).
Habitat
Spawning waters are mostly perennial , i.e. permanently water-bearing small ponds and ponds in rather loamy, less often sandy soils that are exposed to solar radiation for at least several hours a day. They often have both an open water zone and a richly weed reed and underwater vegetation and are eutrophic (but not overly eutrophic!). Since this structure is also preferred by other amphibians, waters with occurrences of the northern crested newt are often characterized by particularly species-rich amphibian communities (associations of different species).
In the vicinity of the water bodies, suitable land habitats must be present with good spatial interlinking, for example grassland interspersed with woodlands, fens , deciduous forests and fringing biotopes such as bank margins, hedges and the like. Very valuable habitat structures sometimes develop in abandoned excavation pits. The animals like to seek protection under stones and lying dead wood and spend the day resting there.
Food and predators
During their mostly nocturnal activity , adult crested newts eat earthworms , slugs , insects and their larvae. Sometimes they even prey on a smaller relative, for example a pond newt. The food is swallowed whole. You can often see newts of various species eating frog spawn. An important component of the food spectrum of aquatic crested newts are various leeches and the tadpoles of frogs. The newt larvae also feed “predatory”; this includes planktonic small crustaceans (including " water fleas ") and insect larvae, which they prey unselectively, ie according to availability.
Combed newts are in turn eaten by various species of birds ( e.g. herons ), snakes (including grass snakes ), mammals ( species of marten , possibly shrews ) and by predatory fish ( e.g. pike , perch ). Their eggs are a popular food for various aquatic animals; the larvae have to watch out for yellow fire beetles and their larvae, various water bugs , dragonfly larvae and fish .
To ward off enemies, crested newts use, among other things, terrifying positions in which they bend over and show the orange underside. They can also secrete a sour-smelling, milky skin secretion that can cause irritation of the mucous membranes in humans. When catching newts, sounds were occasionally heard that were described as “squeaking” or “cracking”. It is unclear whether these are defense or alarm sounds and how they are generated (compare also: fire salamander ).
Hazard and protection
Like all Central European amphibians, crested newts suffer primarily from the destruction or impairment of small bodies of water in the cultivated landscape through the filling up or entry of garbage and environmental toxins (especially pesticides from agriculture). The flooding of fertilizers also pollutes many bodies of water and contributes to their premature silting up through eutrophication . If people put fish in small bodies of water that would not naturally occur there, this usually leads to a collapse of amphibian populations, as their spawn and larvae are eaten by most fish. An excessive number of trees close to the shore also devalues the spawning waters if too little solar radiation can penetrate the water surface.
As "part settlers" with habitats that vary according to the season, crested newts and other species also react sensitively to changes in the landscape in the wider area surrounding the water. The deforestation of hedges and other field trees leads to the loss of summer and winter habitats . Intensive land use as well as the construction and operation of roads have a separating effect between the partial habitats, so that there can no longer be a sufficient spatial exchange of individuals. One speaks of a fragmentation or islanding of the habitats (compare also: European tree frog ). Crested newts and other amphibians suffer considerable losses from road traffic in many places in densely populated Central Europe, in particular when migrating from winter quarters to spawning waters.
Like all amphibians native to Europe, crested newts and their stages of development must not be caught, but must be left in their natural habitat.
Legal protection status (selection)
- Habitats Directive : Annexes II and IV (special protected areas are to be designated / species to be strictly protected)
- Federal Nature Conservation Act (BNatSchG): strictly protected
National Red List classifications (selection)
- Red list of the Federal Republic of Germany: V - warning list
- Red list of Austria: EN (corresponds to: highly endangered)
- Red list of Switzerland: EN (corresponds to: highly endangered)
swell
literature
- Wolf-Rüdiger Grosse, Rainer Günther: Kammolch, Triturus cristatus (Laurenti, 1768). P. 120–141 in: Rainer Günther (Ed.): Die Amphibien und Reptilien Deutschlands. G. Fischer, Stuttgart 1996, ISBN 3-437-35016-1 .
- Andreas Krone (Hrsg.): Der Kammolch (Triturus cristatus). Dissemination, Biology and Protection. RANA special issue 4, Rangsdorf 2001, ISBN 3-9807627-4-2 .
- Andreas Nöllert, Christel Nöllert: The amphibians of Europe. Kosmos-Franckh, Stuttgart 1992, ISBN 3-440-06340-2 .
- Burkhard Thiesmeier, Alexander Kupfer: The crested newt . A water dragon in danger. Zeitschrift für Feldherpetologie, Supplement 1, Laurenti-Verlag, Bochum 2000, ISBN 3-933066-06-9 .
Individual evidence
- ↑ Kammmolch at www.wisia.de
- ↑ Federal Agency for Nature Conservation (ed.): Red list of endangered animals, plants and fungi in Germany 1: Vertebrates. Landwirtschaftsverlag, Münster 2009, ISBN 978-3-7843-5033-2
- ↑ Online overview at www.amphibienschutz.de
Web links
- Information about the northern crested newt in Austria at www.herpetofauna.at ( Memento from August 29, 2011 in the Internet Archive )
- Information about crested newts in Switzerland at www.karch.ch
- Photos of the northern crested newt at www.herp.it
- Triturus cristatus in the Red List of Threatened Species of the IUCN 2009. Posted by: Jan Willem Arntzen u. a., 2008.
- Profile of the crested newt at www.ffh-gebiete
