Ecology:
Bombina bombina is a species, which needs two several aquatic different habitat types and also few terrestrial habitat types. Bombina bombina can only bred in water, so it is completely dependent on water bodies.
Bombina bombina breed both smaller and bigger ponds (50-5000 m2) in Lithuania, Poland and Germany with submerged and floating plant cover. The terrestrial habitat depends on what the local conditions offer and often the terrestrial habitat type and its capacity for feeding and hibernation also have a high influence on the population’s viability and population size. Foraging ponds can have all types of water quality except the acidic one. It’s not unusual that these ponds have muddy bottom and have very eutrophic water or are partly overgrown or shadow covered. Ponds rich in structures with different vegetation zones and dead wood and tree trunks.
Hibernation places are on dryer terrestrial habitats that never floods d ring spring and that are frost free during winter. It can be forest, hedgerows, stone fences and stone piles and house cellars, Bombina bombina migrates between these habitat components and thus its possible with 5 to 6 migrations between habitat components from early spring to late fall. Some time one pond can contain all the necessary pond habitat components which limits the migration.
Bombina bombina feeds on invertebrates and their larvae. In March or April after hibernation the Bombina bombina seek a pond for sun basking and feeding. In May and June the breeding and egg laying takes place in carefully selected ponds, where the males forms large chorus, when they call for the females. After calling season the frogs disperse in to feeding grounds and ponds are often not enough for the larger populations who also seek food in moist terrestrial habitats as fens and meadows. In the End of August or in September the frogs seek towards a hibernation places that can not be flooded by water in winter time. Often they feed during warm days in September and October near the hibernation place.
Population trends:
Nearly everywhere the European lowland populations of this species are declining, mainly due to anthropogenic habitat deterioration. Hence, conservation measures are in urgent need all over its range.
In Lithuania, Bombina bombina is a declining and threatened species. Locally its still common and one of the areas its common it the area where Emys orbicularis lives. Bombina bombina could face a strong decline in near future if Lithuanian landscape will develop as Danish landscape developed after Denmarks entry into the EU in 1972, or as Brandenburg developed after its entry into EU.
In Poland, Bombina bombina is a declining and threatened species. Locally it is still common and some of the areas Emys orbicularis have viable populations of Bombina bombina. However last 10 years monitoring in the agriculture landscape around Bialowieza show many local extinctions in only 10 years time as agriculture intensifies in some cases (moraine soils) or completely stops in other cases (River valleys and floodplains).
In Germany, Bombina bombina is in danger to extinct in several states as Schleswig-Holstein and Niedersachsen and in decline in all former states of East Germany (e.g. Brandenburg). The loss of ponds and overgrowing of ponds and intensive agriculture are the main cause.
