Amphibians are an especially important part of ecosystems, however even the third of their species worldwide are facing extinction. 13 species in total can be found in Lithuania and 5 of them are included in the Red Book of Lithuania. Namely: the great crested triton, European tree frog, fire-bellied toad, green toad, natterjack toad. The rising extinction of amphibians is mainly influenced by the lack of proper habitat. In order to guarantee protection of these and other amphibians the Lithuanian Fund for Nature implemented a number of projects for restoration of their habitats. The organisation is involved in protection of the following amphibians:

European tree frog (Hyla arborea)

The European tree frog is the rarest frog in Lithuania. It is one of the smallest frogs in Europe; it grows up to not more than 3–5 cm length. It has adhesive discs at the end of its fingers, therefore these frogs can climb on a vertical surface. Most often tree frogs are bright green but they can change their colour and become even grey as a consequence of weather conditions and other factors, which are not yet fully understood.

Tree frogs breed in the ponds with rich submersed vegetation and shallow zones. The water surface should be not overshaded, allowing it to be heated quickly by the sun. Adult tree frogs spend a lot of time climbing on the vegetation around their aquatic habitat. They hibernate in the burrows, decaying trees, piles of stones and even in cellars.

Fire-bellied toad (Bombina bombina)

The fire-bellied toad matures to a size of 4 cm. It is perfectly adapted to hide in nature – the skin of the back is bright or dark brown, sometimes green, usually with darker spots. The ventral side is mottled with black-and-white patterns with interfering spots of red and orange colour. When trying to scare predators the toad tries to expose its bright coloured belly. The toad arches its back, raising its front and back legs to display the aposematic coloration of its ventral side. This serves as a warning sign to predators since such bright colours are usually typical to poisonous animals.

This species are found in Eastern and Central Europe as well as Eastern and Central Asia. The fire-bellied toads are protected by Appendix II of the Bern Convention and Annexes II and IV of the EU Directive on Habitats. This species have been registered in The Red Book of Lithuania since the year 1989. Currently the toad falls under the 5th (Rs) category, which covers restored species. The fire-bellied toads typically live in more shallow pools of water if compared to crested tritons. Furthermore, a leafy forest growing close to them is not necessary. Toads spend wintertime in places where temperature remains positive. They establish themselves under the rocks or rock piles, tree roots or in the holes made by other animals. Sometimes in order to spend the wintertime the toads visit people and hide from the cold in their basements. The toads find their winter habitats a few hundred meters away from a water body. Population of fire-bellied toads is declining since there are not enough natural habitats suitable for them. The main reason why the toads are facing extinction is plant coverage of small pools of water and increasing number of fish.

Natterjack Toad (Bufo calamita)

Bright yellow stripe stretching down the middle of the back helps to distinguish this toad from common toads. Adult toads can be up to 7 cm in length, they feed on ants and other invertebrates that can be found on the ground. They have relatively short legs as compared to other amphibians, thus they tend to run rather than jump and sometimes are referred to as “running toads”.

Natterjack toads live in sandy soil habitats, where shallow and sun-heated pools of warm water that are not covered with plants can be found. Therefore, they usually can be found in coastal sites, even though they live in other parts of Lithuania as well. This species falls under the 5th category of the Red Book of Lithuania. More data on its distribution is necessary.  
The natterjack toads are active during the night-time as they spend the daytime in their holes. They spend wintertime deep in holes, which they usually dig themselves. Yet sometimes they use holes dug by other animals or rodents. These toads can live up to 17 years.
Northern part of natterjack toad distribution goes through Estonia. This species are facing extinction in its all range, the main reason of it being the destruction of their habitats – planting heaths with forests or using it for agriculture, pollution of shallow pools of water, sand deans covered with forests or their exploitation for tourism industry. 

Green toad (Bufo viridis)

The dorsal side of this toad shows a green marbled pattern. It breeds in small shallow water bodies.These nocturnal toads prey on invertebrates in the fields covered with sparse vegetation. In the daytime they seek shelter. Burrows, decaying trees, piles of stones or cellars are used for hibernation. Among amphibians,green toads are the ones most adapted to living close to humans – sometimes these toads are abundant in ponds and gardens, they can be seen in greenhouses. Still, the main reason, why the green toad is endangered, is – like with all other rare amphibians - alteration, destruction and fragmentation of suitable habitats.

Common spadefoot toad (Pelobates fuscus)

A spadefoot toad has a smooth skin with marbled pattern. Its pupils are vertical like those of cats. Its hind feet are equipped with spadelike welts, used for digging itself into the earth. Spadefoot toads are nocturnal, during the day they hide underground. If they feel threatened, they can burrow themselves quickly, even at night. In spring, during the breeding period, the males call under the water, trying to attract females. Their voices resemble a muffled thumping. Spadefoot toads can be spotted easiest, when they are in their tadpole stage. Among all tadpoles found in Lithuania, they are the biggest – up to 17 cm length. Occasionally they come up to take a gulp of air in the open water. Adult spadefoot toads are only 6–8 cm long.

Moor Frog (Rana arvalis)

Foto: Vilius Pakevičius
This frog is one of the so-called “brown” frogs. Two species of such “brown” frogs can be found in Lithuania: the moor and grass frog. To distinguish one from another is not that simple. They can be distinguished by their voice and face, whereas specialists can distinguish them from the scoop on the back leg. They spawn in small still water bodies. The males during the spawn time develop a conspicuous blue colouration. After the spawn these frogs go to the land and can be found in fields, meadows and forests. In general, they are found in places not higher than 100 meters above the sea level. The moor frogs are facing extinction in Western and Northern Europe. They are still rather common in Lithuania.

Pool frog (Rana lessonae)

3 species of the so called “green” frogs can be found in Lithuania. One of them is these frogs – small and big pool frogs as well as lake frogs – most of their lives spend in water. The little pool frog, as it can be seen from its name, is the smallest one from the “green” frogs, yet it is hard to tell it apart from other two species when it is seen in the pool. During the spawn time it can be distinguished by its voice and the colour of resonators – little pool frogs have white resonators, whereas other similar species (big pool frogs and lake frogs) have grey ones. There are other not so remarkable features that are difficult to notice for an untrained eye – such as, eyes of the small pool frogs are more yellow than those of the other “green” frogs, moreover its body sides also have more yellow colour. These frogs spawn and live in the sun-warmed pools of water that are covered with flora, perennial pools. Usually they spend wintertime in water as well.

Great Crested Newt (Triturus cristatus)

2 species of newts are found in Lithuania: the common newts (Triturus vulgaris) and crested newts (T. cristatus). Among newts living in Lithuania the crested one is the biggest – adults can grow up to 16-17 cm of length including the tail, yet more often they are up to 12-14 cm length. The skin of the great crested newt is warty. Looking at it from above darker black spots can be seen on a black or dark brown background and only their undersides are covered with small white dots. Ventral side is bright – yellow or orange with black spots. Asymmetrical spots that are on the belly help easily distinguish the great crested tritons from the common ones, since their ventral spots are symmetrical. During the breeding season males are distinguished by their jagged crest.

Typical habitat size of the great crested newt is 25 – 1500 m². Tritons can live in slightly bigger slack waters, yet usually they are not capable of withstanding competition of fish living there. Fish eat larvae of tritons and their population cannot be restored. The great crested triton, being a rather large animal, typically lives in water pools deeper than 0.5 meters. However, shallow, half-a –meter deep waters are no less important since water there is usually warmer and this induces faster development of larvae.
There’s a lack of data concerning distribution of the great crested triton in the territory of Lithuania. It is only clear that distribution of this species in our country is uneven and their number is not as big as that of the common triton. Usually crested tritons are found in Southeastern part of Lithuania. Crested tritons were included in the Red Book of Lithuania in 1991. Currently they fall under the 4th (I) category. Furthermore, these species are protected by Appendix II of the Bern Convention and Annexes II and IV of the EU Directive on Habitats.

In Lithuania tritons are facing extinction due to plant coverage of ponds, reduced number of natural meadows, cutting of forests surrounding the ponds. Certain actions of people also have a great negative impact. Usually, fish, which eat larvae of tritons, are placed in ponds.