Yellow-bellied toad ( Bombina variegata ), young
|( Linnaeus , 1758)|
The yellow-bellied toad ( Bombina variegata ), also Bergunke , belongs within the class of amphibians to the " primitive " family Bombinatoridae (in many overviews will still be the Scheibenzünglern provided) and to the species of toads . The small, pointed black frog has an inconspicuous colored upper side, while the belly side has a bright yellow warning color. The species also occurs regionally in Central Europe and prefers loamy puddles and small pools as a habitat.
The size of the males and females is between 35 and 56 millimeters; in Central Europe, however, head-trunk lengths of more than 45 mm are rarely observed. The upper side is clay to gray-brown, with narrow, darker gland complexes and washed-out light spots sometimes being visible in the neck area. The underside, including the insides of the limbs, fingers and toes, is an intense light yellow to orange in color and interspersed with lead-gray to black spots or areas. Usually the yellow component is more than half of the area (occasionally animals with almost completely yellow undersides appear; but completely black ones have also been observed). Because the pattern on the underside is different for each animal, this enables individual differentiation - for example in the context of zoological studies. Yellow-bellied toads have a stocky body that is not quite as flattened as the related fire-bellied toad ( Bombina bombina ), and a rounded snout. The pupil is heart-shaped, the eardrum is not externally recognizable. The top has numerous warts with raised black horn spines.
The yellow-bellied toad is a inhabitant of the mountain and hill country in central and southern Europe. Specifically, the distribution extends from France via Belgium, the southern tip of the Netherlands (Limburg), southern and central Germany, Switzerland, Austria, Italy north of the Po (further south the Apennine yellow-bellied toad is found ), the Czech Republic, Slovakia, the extreme southern edge Poland, Romania, Bulgaria, the states of the former Yugoslavia and Albania to Greece. In the low mountain ranges of central and southern Germany, but also in the Upper Rhine Plain, it is quite common, but in many places it is only present in scattered populations. The northern limit of the current total distribution is in the Lower Saxony Weser-Leinebergland ( district of Schaumburg ), see also the BfN distribution map .
In the east and south of the distribution area (e.g. Czech Republic, Eastern Austria, northern Balkan Peninsula), the area of the yellow-bellied toad partially overlaps that of the red-bellied toad. Here it can occasionally come to hybridization between the two species, whereby the resulting hybrids have characteristics of both parents.
Habitat and way of life
The yellow-bellied toad is one of the amphibians with close ties to water. Originally, the species was a typical inhabitant of the stream and river meadows. Here it settled the temporary small bodies of water that are constantly emerging depending on the floodplain dynamics. In its civilizing substitute biotopes, too, it temporarily prefers water-bearing small and micro bodies of water on loamy ground, such as tractor tracks, puddles and small moats. Most of them are poor in vegetation and free from competing species and predators. The rapid warming of the waters ensures that the spawn and larvae develop quickly. You can find this pioneering species today mainly in quarries, clay or gravel pits and on military training areas.
The high mobility of the young animals favors the spontaneous colonization of newly emerging habitats. On land the animals look for hiding places under stones, dead wood and in systems of gaps and crevices in rocks. Predominantly at twilight and nocturnal, they hunt for insects (beetles, ants, two-winged birds, etc.). Their predators include back swimmers, oar bugs, dragonfly larvae, newts and sticklebacks (for the tadpoles) as well as birds such as magpies and blackbirds (for the young and old animals).
When in danger, the yellow-bellied toad sometimes takes the so-called boat position. She makes a hollow back so that the edges of her intensely colored belly and the insides of her limbs are visible from above (compare: Toad reflex ). This is to warn predators of the skin poison that they secrete in this situation. The poison is not dangerous for humans, but it is very irritating to the mucous membranes.
Reproduction and Individual Development
The mating calls of the males can be heard in late spring and early summer as a dull but melodious "uh ... uh ... uh". Since the species, unlike the fire-bellied toad, has no sound sockets , the calls are only very quiet. The sound sequences are repeated more than 40 times per minute and thus significantly more numerous than with the fire-bellied toad. Calling and spawning activities (up to three periods per year) are often stimulated by heavy rainfall, because often only then are the preferred micro bodies of water available. The males do not cling to the females behind the front legs as in the case of the real toads or most frogs, but rather in the hip region.
The eggs are attached by the couple in loose clumps of 2 to 30 eggs to submerged blades of grass and similar structures; a female can produce 120 to 170 eggs annually. The eggs are medium brown on the upper side and light brown on the lower pole and have a diameter of 1.5 to two millimeters, the jelly shells are five to eight millimeters. The main spawning season in Central Europe extends from May to June.
The tadpoles hatch after two to three days. The upper fin edge of the older larvae, which was last no more than 55 millimeters long, reaches no more than the middle of the trunk; the end of the tail, which is quite short in relation to the body, is rounded. The animals have a dirty gray base color. The duration of larval development depends on the ambient temperature and is usually between 41 and 67 days. The converted metamorphic blanks (young tokens) then have a length of 12 to 16 millimeters. After one or two hibernations, young animals reach sexual maturity and take part in the reproductive process themselves. A toad lived to be 27 years old in captivity.
A threat to the occurrence of the yellow-bellied toad comes primarily from habitat losses, such as those caused by the backfilling of ponds, the expansion of unpaved forest paths and back alleys, but also through natural succession (especially the encroachment) of the pioneer biotopes. As a result of spatial isolation , i.e. fragmentation of the habitats (for example through roads or intensive agriculture), occurrences are separated from one another. This restricts the genetic exchange between the populations and the immigration from outside, which ultimately endangers the viability of the isolated populations.
Legal protection status (selection)
- Fauna-Flora-Habitat-Guideline (FFH-RL): Appendices II and IV (special protection areas are to be designated / species to be strictly protected)
- Federal Nature Conservation Act (BNatSchG): strictly protected
- Classification as a type of responsibility for Germany within the National Strategy for Biodiversity of the Federal Government
National Red List classifications (selection)
- Red List Federal Republic of Germany: 2 - highly endangered
- Red List of Austria: EN (corresponds to: endangered cat. A.3)
- Red list of Switzerland: EN (corresponds to: highly endangered)
To support small populations, artificial reproductive waters, such as buried concrete pools, can help. These are installed in a narrow strip along a ditch or stream. Investigations showed that the artificial small bodies of water were accepted by the toads after just a few days and remained occupied throughout the summer and were used for spawning.
- Birgitt Gollmann, Günter Gollmann, Kurt Grossenbacher: Bombina variegata (Linnaeus 1758) - yellow-bellied toad. In: Kurt Grossenbacher (Ed.): Handbook of the reptiles and amphibians in Europe. Volume 5 / I Froschlurche (Anura) I (Alytidae, Bombinatoridae, Pelodytae, Pelobatidae), pp. 303-361. ISBN 978-3-89104-006-5 .
- Andreas & Christel Nöllert: The amphibians of Europe. - Franckh-Kosmos, Stuttgart 1992. ISBN 3-440-06340-2 .
- Klaus Lörcher: Comparative bio-acoustic studies on the red and yellow-bellied toad, Bombina bombina (L.) and Bombina v. variegata (L.). In: Oecologia (Berlin), Volume 3, 1969, pp. 84-124.
- Hans Joachim Obert: The spermatogenesis of the yellow-bellied toad (Bombina variegata variegata L.) in the course of the annual activity period and the correlation to mating call activity (Discoglossidae, Anura). Journal for microscopic anatomical research, Volume 90, 1976, pp. 908-924.
- Ernst Schmid: The call apparatus of the red and yellow-bellied toad and the midwife toad Bombina bombina (L.), Bombina v. variegata (L.), Alytes o. obstetricans (Laur.) (Anura, Discoglossidae). Zoological Yearbooks, Anatomy Department, Volume 98, 1977, pp. 171-180.
- Hans Schneider: The mating calls of native frogs (Discoglossidae, Pelobatidae, Bufonidae, Hylidae). Journal of Animal Morphology and Ecology. Volume 57, 1977 pp. 119-136.
- Hans Schneider, Fawzy Hussein, Mamdouh Saad Ahmed Akef: Comparative bio-acoustic studies in the yellow-bellied toad, Bombina variegata (L.), and relationships of European and Asian species and subspecies of the genus Bombina (Anura, Amphibia). Bonn zoological contributions, Volume 37, 1986, pp. 49-67.
- Hans Schneider: Bioacoustics of the Froschlurche - native and related species. With audio CD. Supplement to the Zeitschrift für Feldherpetologie 6. Laurenti Verlag, Bielefeld 2005. ISBN 3-933066-23-9 .
- Eleni Vasara, Theodora S. Sofianidou, Hans Schneider: Bioacoustic analysis of the yellow-bellied toad in northern Greece (Bombina variegata scabra L., Anura, Discoglossidae). In: Zoologischer Anzeiger, Volume 226, 1991, pp. 220-236.
- Lurch of the year 2014: The yellow-bellied toad ( Memento from December 27, 2013 in the Internet Archive ) (accessed December 5, 2013)
- Yellow-bellied toad in the Schaumburg district ( Memento from February 22, 2014 in the Internet Archive )
- Yellow-bellied toad distribution in Germany
- Yellow-bellied toad at www.wisia.de
- Species in particular responsibility of Germany ( memento of August 2, 2017 in the Internet Archive ) on the homepage of the Federal Agency for Nature Conservation, accessed on June 3, 2016
- Online overview at www.amphibienschutz.de
- Kurz, M. & Zehm, A. (2015): Securing the population of the yellow-bellied toad through artificial spawning grounds. - ANLiegen Natur 37/1, pp. 12–13, Laufen.
- Photos of the yellow-bellied toad at www.herp.it
- Yellow-bellied toad - Bombina variegata (LINNAEUS, 1758) ( Memento from September 19, 2010 in the Internet Archive )
- Images ( Memento from August 4, 2012 in the Internet Archive )
- Information and pictures at www.amphibienschutz.de
- Calling yellow-bellied toad (video)
- Bombina variegata in the endangered Red List species the IUCN 2007. Posted by: Kuzmin et al, 2004. Retrieved on 12 May 2006..