The Yellow-bellied Toad (Bombina variegata)
The Yellow-bellied Toad (Bombina variegata) is a typical pioneer species in dynamic habitats that are rich in structure. This species can reach sizes up to 6 cm. It has a flattened body and the warty upper side is light to dark shades of grey-brown with partly dark-brown to olive-brown shadings. The distinguishing mark of this anuran species is the individual yellow-black/grey pattern of the underside and the heart-shaped pupils.
The northern distribution boundary of the Yellow-bellied Toad runs across Germany. Germany offers nearly 15% of the whole distribution range and therefore has a particular responsibility to protect this species. Here, the core area of the distribution of the Yellow-bellied Toad is located in Bavaria and Baden-Wuerttemberg, where it can be found in many areas. However, populations in the northern part of the distribution range in Germany are highly isolated from each other.
© DGHT registered association. (Ed. 2014): Dissemination atlas of amphibians and reptiles in Germany, based on data from the federal state authorities, expert working groups and NABU federal state expert committees of the federal states as well as the Federal Agency for Nature Conservation.
In general, Yellow-bellied Toads live in dynamic habitats, which offer a high diversity in structure. For reproduction, this species is dependent on unshaded, shallow waterbodies with spare vegetation. Originally, these waterbodies arose from flood dynamics along rivers of the low mountain regions as well as floodplains of rivers, where flooding regularly generated new waterbodies. Nowadays, this species is mostly restricted to secondary habitats where human activity regularly generates new pools, such as stone, gravel, sand and clay pits as well as military training grounds,
During breeding season, males are easily distinguished from females due to their nuptial pads. These nuptial pads serve to adhere to the female in the inguinal region during mating. Mating season continues from April to August. In this period, an adult female lays approximately 100 to 200 eggs, which are attached separately or in clumps consisting of 10 – 20 eggs to dead vegetation, to blades of grass dangling into water or to the soil of shallow, unshaded pools. Following the principle of distribution of risk, females spread their spawn in several waterbodies.
The dramatic decline of the Yellow-bellied Toad is predominantly attributed to the disturbance and loss of habitat respectively. Moreover, the remaining populations are often highly isolated so that a migration of single specimens for genetic exchange is not possible.
Due to the high population decreases in Germany, the Yellow-bellied Toad is in a bad state of preservation and therefore listed in annexes II and IV of the fauna-flora-habitas Directive. In addition, referring to the Red List, this species is categorized as “critically endangered” in Germany and “threatened with extinction” in Lower Saxony, North Rhine-Westphalia and Thuringia.
Literature reference: Gollmann B, Gollmann G (2012): Die Gelbbauchunke von der Suhle bis zur Radspur. Laurenti-Verlag, Bielefeld.