Marsh frog

Marsh Frog ( Pelophylax ridibundus) of Krk / Croatia

The marsh frog ( Pelophylax ridibundus or Rana ridibunda ) is within the order of Anura to the family of the Real frogs ( Ranidae ). In addition, he is expected to follow appearance, biology and distribution of the water frogs that have recently been questioned by many authors in a separate genus Pelophylax. Within this hard to looking complex of marsh, although deemed to be kind - not like the frog pond, as hybrids - but the exact taxonomic status of Seefrosches is not yet fully understood. Perhaps the species here treated as Pelophylax ridibundus still needs to be split into several types.

Features

The head -body length ranges from 10 to 16 centimeters; Specimens over 10 inches are mostly females. The top is usually olive green or olive-brown, in Central Europe hardly grass green, with distinct dark spots. The wasserfrosch typical green dorsal midline is usually present. The inner thighs are white - gray and black marble ( yellow components usually missing); the paired vocal sacs of the males are dark gray. The conformation similar to its relatives Pool Frog and Frog Pond, albeit with different proportions. Thus, the hind legs and lower legs are very long in relation to the hull. The hock is small and flat.

Reproduction

The males call " oäk, oäk " ( Revierruf ) and loud and sonorous " reck - perky - perky - perky - perky " ( mating call ) in choppy sound sequence, so it sounds like a strong laugh (see epithet ridibundus = the Laughing ). All water frogs call at night and during the day, then above all, in sunshine and in central Europe from April to June.

It is sold in a body of water spawn clumps, which are generally much smaller than in the brown frogs ( cf. grass frog) and remain submerged. The eggs are brownish on the upper side, the lower pole is colored bright yellow. In Central Europe, the spawning is usually found between late April and late May. A single spawn clumps often contains "only" a few hundred eggs; but the females put several bales after the other. Overall, it can produce up to 16,000 eggs per season, a female; the Eidurchmesser is 1.5 to two millimeters.

Older tadpoles, with a greenish ground color and dark speckle pattern falling on by headlong flight reactions. The overall length ranges from 40 to 80 millimeters. A distinction from other Wasserfroschquappen is certainly possible.

Habitat and Distribution

The marsh frog has a very close bond with water. Even juveniles be removed only a few meters from the waters. Seefrösche prefer this larger, more eutrophic waters in the floodplain, such as lakes, backwaters, oxbow lakes, flood channels, quiet stretches of river, Bracks, larger ponds and lakes, sometimes channels and wide trenches. A rich water and riparian vegetation is advantageous, however, should take place no shading by trees. There the animals like to sit on the shoreline and sunbathe. With danger and disorder they immediately jump into the water. Hibernation takes place, unlike most other anurans, mainly aquatic sediment in the water. The species is therefore dependent on oxygen-rich, very rare or long term satisfied Rende waters.

The putative " collective species marsh frog " is particularly common in central and eastern Europe as well as in Middle East and Central Asia. To the west, her complex dissolves into discontinuous sections which coincide strikingly with the great river landscapes. In the northwest German lowlands pure populations of Seefrosches in East Friesland and the Weser march are remarkable: Here comes next Pelophylax ridibundus no other water frog shape. Otherwise rather mixed populations with the pond frog hybrids are common. A large-scale dissemination gap calculated in Mecklenburg- Vorpommern ( Mecklenburg) is striking.

Food

Seefrösche feed on insects, spiders, worms, and even cannibalistic smaller anurans and other dogs as well as their larvae. The tadpoles eat ( filter ) diatoms, green algae, rotifers, protozoa, detritus and the like; later they scrape and soft Wasserpflanzenteilchen. In older specimens but also takes the proportion of animal food (such as small crustaceans, annelids ). Also occurs Laichkannibalismus.

Threats and conservation

Seefrösche because of their relatively stationary lifestyle probably less threatened than many other amphibian species. Even in some fish ponds - which should have reeds entangled bank, however, at least - they can survive better than the other amphibians ( with the exception of the common toad ). At the edge of their distribution area, including in Germany, however, the kind often seems to have no such great ecological power as the center of the distribution. Expression of this is the strong concentration of river valleys and marshes, while large regions in between are uninhabited.

Legal protection status (selection)

• Fauna-Flora -Habitat Directive (FFH Directive): Annex V (Article may be subject to management measures )
• Federal Species Protection Ordinance ( BArtSchV ): specially protected

National Red List classifications (selection)

• Red List Federal Republic of Germany: not threatened
• Red List of Austria: VU (corresponds endangered)
• Red List of Switzerland: NE ( not rated)