Fire Bellied Toad

Tympanic membrane absent. Transversal processes of the vertebra sacralis notably widened. Pupil of the eye triangular. Skin tuberculate. Dorsal tubercles rounded rather than coming to a point. Dorsal surface dark-grayish to almost black, with large dark spots. In pools with opaque water, a sandy bottom and scarce riparian vegetation, the toads sometimes possess a bright-green dorsal coloration with scarce dark-green spots. Belly red or orange, with large bluish-black spots and numerous white points. On the belly, the bright coloration does not exceed the dark coloration in area. The inner surface of the leg is covered with small bright spots, which are not fused. In contrast to the female, the male has internal resonators, a slightly larger head and, during the breeding season, black nuptial pads on the 1st and 2nd fingers and on the inner surface of his forearm.

The species inhabits Central and Eastern Europe. The Central European part of the range is divided by the Carpathian Mountains. The glacial refugia of B. bombina are supposed to be in the steppes bordering the Black and Caspian seas. The western margin of the range runs approximately by Germany (Schlezwig-Holstein, Lower Saxony, Sachsen-Anhalt, Dresden and Gorlitz), Czech Republic, Northeast Austria, Eastern Yugoslavia, Greece, Bulgaria, Romania and Western Turkey. The northern margin of the range runs from the area southwest to the Swedish province of Skane through Denmark to the Baltic Sea through Byelorussia and Central European Russia to Preuralia (Bashkiria) and Urals (Chelyabinsk Province). The southern margin of the range seems to be limited with the mountains of Balkan Peninsula; however, it occurs in Western Turkey (Anatolia: Sakarya River). The toad is known from the Northern Crimea. In the south of the European part of the former Soviet Union it occurs mainly in river valleys, including those in Precaucasia and Precaspian region. Then the range extends through the Southern Urals to the Northern Kazakhstan.The toad inhabits zones of steppe, forest steppe, broad-leaved and mixed forests consisting of different species of trees. In the forest steppe and steppe zones, B. bombina inhabits bushlands, forests and wetlands in floodplains, covered with dense vegetation. It inhabits also open landscapes, using drainage channels as pathways for dispersal. At the southeastern margin of its range, the species lives in permanent freshwater bodies in river valleys surrounded by an arid saline landscape. It is primarily an aquatic animal living in shallow stagnant lakes, ponds, swamps, peatbogs, ditches, flooded rice fields and quarries. Sometimes the toad inhabits semi-flowing waters: springs, irrigation channels, rivers and stream pools. In some areas, however, it seems to live almost entirely in stagnant water bodies. As a rule, the water must be clear. In the Carpathian region, B. bombina lives in wetlands with clearer water than the congeneric B. variegata. However, near the southern margin of the range, in Southeastern Ukraine and Krasnodar Region of Russia, the toad often occurs in chemically polluted waters: settling and sedimentation reservoirs, rice fields, polluted ponds in settlements and cities etc.

In the West Europe this species is significantly declining or extinct in many areas. There it largely depends on conservation of wetland habitats. However, over large areas of the European part of the f. USSR, the Fire-Bellied Toad is a common or numerous amphibian. For example, in Byelorussia its proportion averages 0.4-3.4% of all amphibians. At suitable sites in lowland Ukraine, the toad's abundance reaches 200 individuals per a hectare of pond surface. In central European Russia, the toad's density reaches 20000, and in Precaucasia varies within 0.6-26453 individuals per the same square.The toads prefer relatively warm conditions: they are active at +10 - +30oC, usually +18 - +20oC. Active individuals are found in the daytime, but the maximum calling by males occurs at dusk, whereas during windy or cold weather toad activity decreases. Fire-Bellied Toads stay in the water or near the shore; terrestrial migrations occur mainly at high air humidity, as a rule at night.Hibernation occurs from the end of September or October (sometimes the beginning of November) to late March or April. The toad hibernates in the mud on the bottom of water bodies or on land. The breeding season extends from May to the end of summer. During this time, male vocalizes floating on the water surface, with body flattened. Sometimes he is able to call from under the water. Amplexus is pelvic. The clutch contains 80-300 eggs, sometimes more, deposited in portions. Embryonic and larval development takes 2-2.5 months. Metamorphosis extends from the second half of June to the end of September. As a rule, it peaks in July-August. Recently metamorphosed toadlets stay in the water and near the shore. Sexual maturity is attained in the 2nd-4th year of life, longevity in nature reaches at least 12 years.Tadpoles consume mainly algae and higher plants, lower animals frequently are eaten. Newly metamorphosed toadlets prey mainly on insects (Coleoptera, Hymenoptera, Diptera), as do adults, which consume mainly insects. More than half of their diet of adults may consist of aquatic invertebrates, but terrestrial animals are also numerous. Variation in the proportion of aquatic prey in different samples reflects the extent of terrestrialism the toad in different landscapes and seasons. During the breeding season, feeding is not stopped.When faced with a potential predator, B. bombina exhibits a defensive posture called the unkenreflex. It turns over and curves its bright belly upward, covering the eyes with its palms. Otherwise, it may not turn over but instead curve its body downward, lift up the head, and curve the extremities showing the bright spots on its flanks and on the ventral surface of the extremities. Despite the venomous skin secretions in the Fire-Bellied Toad, many vertebrates regularly consume its adults and juveniles. For example, up to 25% of the diet of Night herons (Nycticorax nycticorax) in Ukraine may consist of Fire-bellied toads.

Destruction of wetlands is the most serious threat to populations. This led to decline or extinction of this species from many areas of the West and Central Europe. Such phenomena are known from Sweden, Germany, Denmark and many other countries. In the former USSR such phenomena were recorded locally, mainly in surroundings of cities, near enterprises, in agricultural landscapes where artificial fertilizers were used, etc. In this region the species is numerous or common and not threatened.

As noted above, the destruction and pollution of habitats are main threats for the species populations. The Fire-Bellied Toad is rare in cities. Nevertheless, at the southern margin of the range (Precaucasia) the toad inhabits even polluted wetlands, such as sedimentation reservoirs, rice fields etc. Some kinds of human activity are profitable for the toad: it uses drainage channels as pathways for dispersal.