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Great Crested Newt

Who is the great crested newt?

The great crested newt (Triturus cristatus) is a dark lizard-like amphibian measuring more than 14 cm in length. Similarly to that of toads, its skin is scabrous and black or dark grey. The stomach is bright yellow or orange, with black spots.

The animal has received its name after the tall dentate crest that the male develops on its back during breeding season (in April). The great crested newt is often confused with another newt living in Estonia – the smooth newt. While it is considerably smaller than the great crested newt (up to 11 cm) and has smooth light brown skin, the confusing factor lies in the fact that male animals also develop a tall crest during breeding season. It is possible to tell the males of the two species apart by knowing that the smooth newt’s crest runs straight from the back to the tail, while that of the great crested newt is interrupted on the base of the tail with an incision and then continues along the tail.

The male develops a tall dentate crest during breeding season

Life cycle

In late March and April the adult newts leave their hibernating sites and return to water bodies to breed. An original courtship ritual takes place here: the male shows off by “dancing” in front of the female, shaking its bent tail and pointing it at her. The female lays up to 400 small white eggs, attaching them singly to the underside of water plant leaves. The leaves are folded around the egg so that the eggs are firmly hidden (siia võiks panna määrajas kasutatud pildi volditud lehega). After breeding, adults progressively leave the ponds. The larvae stay in the breeding ponds until July-August, in Finland even till October.

Great crested newt larva

Habitat

The great crested newt is an amphibian living in very close contact with water. It prefers small lakes, forest ditches, village and sauna ponds, beaver floodings and water bodies situated in quarries.  The great crested newt makes rather high demands on the water bodies: it prefers small water bodies with clean and clear water, at least partly exposed to the sun, with shallow water plants (water mint, pondweed) and without fish. These water bodies should also be situated in groups close to one another no more than 500 metres apart, which is the distance that the great crested newt is capable of crossing on dry land.

Besides water bodies the great crested newt also needs terrestrial habitats and suitable hibernation areas. Great crested newts can be spotted on dry land (meadows, deciduous forests, gardens) in the second half of the summer. At daytime they hide under rocks, tree stubs or stumps or dig into moss. Only in the dark of night do they come out to feed.

The great crested newt prefers to hibernate in various dens, below stumps and stone piles, but it can often be found in cellars as well.

In Estonia the great crested newt often lives in sauna ponds and quarries

Distribution

Great crested newt distribution in Estonia

The great crested newt is mainly found in Northern and Central Europe, north of the Alps. It is absent from Ireland and most of Scandinavia. Its distribution area extends to Finland in the north, Russia and the Ukraine in the east, finally reaching South-East Asia.

In the past century the great crested newt was dispersedly present in all of mainland Estonia. It was particularly numerous in South-East and South Estonia, where in addition to natural water bodies found in abundance in domed landscape, each farm had several smaller water sources, such as flax soaking holes, cattle watering spots and sauna ponds. As the water bodies were situated close to one another, they formed a network of sorts, which constituted an extremely favourable living environment for the great crested newt.

The social and economic changes that took place in the second half of the XX century had a considerable impact on nature as well. Flax-growing and cattle-keeping decreased significantly. Former flax soaking holes and cattle watering spots grew over or were redesigned into fish ponds.  Many small water bodies filled up with brushwood, silted up and finally withered away. The distribution areas of several amphibian species began to diminish and their number went into a rapid decline. The same happened to the great crested newt. This species can still be found today in Võru, Põlva and Valga counties, but the preserved localities are situated far away from one another and the number of individuals is small. As for the rest of Estonia, single preserved sites are known to be situated in the Pandivere uplands and in Järva and Jõgeva counties.

Threats

The lack of small water bodies suitable for breeding constitutes the main reason for the decrease in the great crested newt’s numbers.

Overgrowth of water bodies

When water bodies are no longer in use (due to ceased flax-growing, decreased cattle-keeping, deserted farms) they grow over with tall water plants and finally with brushwood. Piling of plant parts causes silting and water bodies start lacking in oxygen, which hinders spawn and tadpole development. In time these water bodies become completely overgrown with brushwood and finally disappear.

Populating water bodies with fish

Although smaller fish do not eat adult great crested newts, they are fond of their spawn and tadpoles. As great crested newt tadpoles mainly feed in the open parts of water bodies, they constitute easy prey for fish while they swim around.

The rapidly breeding crucian carps root up bottom sediments, destroy water plants, thus throwing the ecosystem of small water bodies out of balance. Clear pond water fills up with greenish algae and becomes opaque and lacking in oxygen.

A water body full of brushwood and algae hinders spawn development

Drainage of water bodies

Small water bodies situated in the middle of fields and meadows are drained and filled up to facilitate agricultural vehicles. This practice was common in Estonia mainly during the second half of the past century in the times of collective farming, while the threat still persists in the rest of Europe in areas with intensive farming.

Destruction of pond clusters

A great crested newt population is at its most viable when it can populate several water bodies situated close to one another. When only a single pond remains, the whole population depends on it. If something happens to that pond, the whole population perishes.

Intensive farming

Breeding ponds are often situated in the middle of fields and cultivated grasslands. Pesticide toxins and fertilisers affect amphibians, including the great crested newt both directly and indirectly. Fertiliser pellets sticking to the animal’s skin are absorbed through the skin and poison the great crested newt. Pesticides have a direct impact as toxins as well as an indirect fatal impact through food.

The accumulation of fertilisers in water bodies decreases water quality and triggers the thriving of water plants, as a result of which ponds rapidly grow over and become unsuitable for breeding.

Breeding pond in an area of intensive farming

Intensive forest management

The great crested newt often forages and hibernates in deciduous and mixed forests. Unlike coniferous forests, they have more light, more food and hibernation sites. Clearing these forests and replacing them with spruce plantations deteriorates great crested newt habitats – a tendency, which is particularly visible in Finland.

How to help the great crested newt?

Our everyday actions have an involuntary impact on many living beings – we either create suitable living conditions for them or destroy them. In reality, every pond or puddle owner can do things to help the great crested newt and other amphibians.

• "Preserve small ponds and puddles and keep the pond banks from growing over with brushwood and the pond from filling up. This way, in addition to preserving the diverse water biota we maintain the beauty of the whole landscape and create a more pleasant living environment for ourselves as well.
• "Do not populate water bodies with fish. If you still wish to grow fish, always keep some ponds free of them. We can always find compromises between our wishes and the nature’s needs.
• "Restore small water bodies. If it is possible, you will have contributed to the preservation of nature’s diversity more than you know.
• "Do not cultivate the area surrounding ponds situated in the middle of fields. A stretch of at least 5 metres impedes (decreases the amount of) fertilisers from finding their way into the water body and provides the amphibians with a necessary feeding area just on the edge of the water body.

By managing water bodies we create favourable conditions for the great crested newt