The Italian crested newt (Triturus carnifex) is the largest crested newt species in Europe. It is recognized by its light brown to dark grey coloured back with dark spots and yellow-orange abdomen with a distinctive pattern of irregularly shaped dots. Several tiny white spots are visible on the dark throat. The sexual dimorphism is noticeable during the breeding season when males develop a pronounced dorsal crest. Females and young specimens often have a continuous yellow line along their backs and never grow a dorsal crest.
The Italian crested newts spend two-thirds of their lives on land, where they usually hibernate. They come to the breeding sites in late February or early March, where they usually stay for up to three months. During the mating period, the male establishes a temporary territory from which he chases away other males and courts with the females. After the fertilization female lays about 200 eggs, which are individually wrapped in leaves of floating or submerged aquatic plants. The larvae that are laid from the eggs can actively swim in the water and are therefore easy prey for predators, especially fish. Adults are active mainly at night. The Italian crested newt can be frequently found on the bottom of the ponds between aquatic vegetation and only come to the water surface to breathe.
The Italian crested newt has a distribution centred around Italy and Slovenia, parts of Austria, Croatia, Bosna and Hercegovina, Hungary and the Czech Republic. Species occurs only in Slovenian project areas and is widespread in Slovenia.
The Italian crested newt is a resident of a variety of temporary and permanent, stagnant or slow-flowing waters with many aquatic plants that are free of fish. It is often found in anthropogenic habitats such as ponds, stone wells, cisterns and water tanks, quarries and sandpits. For the presence of the Italian crested newt, a sufficient number of suitable aquatic habitats and an appropriate terrestrial habitat such as grasslands, shrubs and borders with many hiding places are important.
The species is threatened by the rapid loss of suitable aquatic and terrestrial habitats. As the Italian crested newt is very sensitive to changes in water quality, agricultural intensification and the pollution of water by pesticides, fertilizers and municipal sewage are among the most important risk factors. Drying up of aquatic habitats and urbanization of the landscape has a negative impact on populations. They are also at risk of introducing fish in water bodies that actively prey on eggs, larvae and adults.
Italian crested newt metapopulation dynamic in Slovenian project areas is highly dependent on connectivity between surrounding terrestrial woodland habitats and ponds in the wetland. Main national roads in project areas are situated on the border between forest and wetland, which makes traffic road mortality a significant threat for them.
Interesting facts about Italian crested newt
As all crested newts, males perform ritualized courtship at underwater leks to wow the females. They congregate and perform elaborate dances, meanwhile wafting pheromones toward females to further entice them. When a female is taken in by a particular male’s display, he creeps away and she follows him. Once she signals her interest by touching his tail, the male deposits a spermatophore (a package of sperm) and guides the female over it. Finally, the female takes up the spermatophore with her cloaca. Eggs are fertilized internally and as the female lays her clutch in the aquatic vegetation, she gently wraps each egg in a leaf.
Crested newts are mostly terrestrial but return to the water each year to breed. The sexual dimorphism is noticeable during the mating season when males have a deeply notched middorsal crest which extends from the level of eyes to the base of the tail. A longitudinal blue-white band can be seen on the tail of males. Females are without crest, but sometimes have a yellow dorsal line, that we can also observe in juveniles.