Common Garlic Toad
| Common Garlic Toad | ||||||||||||
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Common spadefoot toad ( Pelobates fuscus ) |
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| Scientific name | ||||||||||||
| Pelobates fuscus | ||||||||||||
| ( Laurenti , 1768) |
The common spadefoot toad ( Pelobates fuscus ) is a frog and belongs to the genus of European sea-toed toads ( Pelobates ) within the superfamily of toad frogs . With the sharp-edged, horny growths on the soles of their feet, they can very quickly bury themselves in loose soil where they spend the day. Due to its hidden way of life and its scattered distribution, the species is generally little known. In order to draw attention to its endangerment in nature, it was named " Lurch of the Year " 2007.
features
Adult males reach a maximum body length of 6.5 cm, females a maximum of around 8 cm; on average, however, both sexes remain somewhat smaller. The color of the common toad varies depending on its lifestyle, regional occurrence and gender. Usually the animals show irregular dark brown, often elongated, island spots on the upper side on a light gray to beige-brown ground. Almost every animal can be individually distinguished. There can also be reddish or brown warts, and red spots on the flanks. Females are usually more reddish-brown in color, while males tend to have gray or clay-yellow tones. In addition, the latter have thickened humerus glands during the mating season. Some copies are almost completely missing the markings. During the stay in the water, many animals darken and thus have a temporarily poorer contrast pattern.
The belly is whitish in color, often with light to dark gray speckles. Occasionally, albinotic forms also occur. Further distinctive exterior features a helmet-like "apex bump" on the back of the head as well as the vertical slit-shaped pupil as otherwise only under the Central European anurans midwife toad has. The heel hump ( callus internus ) on the soles of the feet of all frogs is particularly enlarged, sharp-edged and hardened in the common garlic toad. It serves the animal as a "grave shovel" (grave callus; compare way of life).
This characteristic - as well as the pupil shape - is shared by the species with its close southern European relatives, the razor foot ( Pelobates cultripes ) and the Syrian red toad ( Pelobates syriacus ), but also with the American red toad (Scaphiopodidae). The color of the grave calluses varies depending on the species - in the common garlic toad they are light brown in color.
The eponymous garlic smell , which is said to be associated with this frog, is only noticeable when there is a strong startle reaction. The secretion given off serves to defend against the enemy. The repertoire of behavior in defending against enemies should also include actively attacking and biting the opponent as well as uttering a startle cry that is similar to a toddler's cry. However, passive behaviors such as inflating the body or crouching down can be observed much more regularly in threatening situations.
Reproduction and Individual Development
( The following phenological data generally refer to the Central European lowlands.)
With the arrival of significantly frost-free, rainy nights (mostly around the end of March), spadefoot toads set off from their winter quarters to the breeding waters. They appear here in normal years with winter weather until February / March in often only a few days delayed from typical "Frühlaichern" as common toad or frog , with males as some are in most amphibian species on average active earlier than females.
The mating calls of the males - females are also capable of making sounds - are very quiet due to the lack of sound bubbles and are also usually uttered under water. As a result, they are only audible to the observer at close range. They sound like "wock .. wock .. wock" or "klock .. klock .. klock". The main calling and spawning time is between the end of March and mid-May. Triggered by extensive rainfall in the height of summer, a second courtship and spawning phase (secondary spawning season) occasionally takes place. In the case of the amplexus , the female is clasped by the male in the lumbar region - this is typical of the more original species of Mesobatrachia and Archaeobatrachia ("primordial frogs").
The spawn , which is wrapped in a spiral around vertical plant stems, differs from that of the real toads (thin cords) as well as that of the frogs (balls or clumps): They are thick gelatin cords about 40-70 cm long and one and a half to two centimeters in diameter. They contain between 1200 and 3400 brown-black eggs. After four to ten days of embryonic development, the tadpoles hatch. The older stages of development are noticeably large and move like a fish, with a total length of 9 to 12 centimeters - exceptionally also over 20 cm - significantly larger than many other frog larvae. When viewed from above, they have eyes that are noticeably far apart (as is usually the case with Central European species only tadpoles of the tree frog ) and have relatively strong, dark horned beaks. They like to swim just below the surface of the water in warm layers of water, so that they can dive down in a flash when alarmed and hide in the mud. Even when they leave the larval water (end of June and in July, sometimes later), i.e. when the metamorphosis is complete , the animals are comparatively large: at 2 to 3.5 cm, they have shrunk considerably compared to the larval stage, but are still a good double long like most other freshly metamorphosed frogs in Europe. Garlic toads can become sexually mature after a year; however, they usually only take part in the reproductive process in the second year after the metamorphosis .
Habitat, way of life
The adult toads, apart from the spawning season, are ground-dwelling land animals. They particularly prefer landscapes with loose, sandy to sandy-loamy topsoil (for example heaths, inland dunes , grasslands, steppes). Here the animals can quickly dig in with their heel hump "shovels" on their hind feet and the specially adapted leg muscles. According to a study from northwest Germany, the burial depths are only between 1.5 and 8 centimeters during the spawning season, depending on the type of soil and the environment, but probably significantly deeper during the rest of the time (around 10 to 60 cm). The excavated caves are used several times by the animals. If the environmental conditions are optimal, the underground daytime hiding spots are literally expanded into a living cave, with the walls being mechanically stabilized and strengthened by the common garlic toad. In very dry summers, there can occasionally be longer periods of inactivity, during which the toads rarely leave their burrow.
As soon as dusk falls, the animals dig their way out of their underground hiding place in order to look for food on the surface. Garlic toads are mainly insectivores. Their diet consists mainly of beetles , field crickets , grasshoppers and smooth caterpillars, but also woodlice , small to medium-sized snails and earthworms . They themselves belong to the prey spectrum of various bird and mammal species. The most important predators are owls such as the tawny owl (for adult toads) and in particular the mallard when devouring spawn and larvae. In addition, herons , storks and birds of prey also appear as predators of tadpoles and adults (see also: red-footed falcon ).
Garlic toads have benefited in many ways from agriculture and its tendency towards ever larger arable land (but compare also: endangerment). The more open, worked ground areas with loose grain, the more frequently the animals migrate into these habitats. Garlic toads particularly like to colonize sandy potato and asparagus fields ("potato toad ").
Small to medium-sized, eutrophic still waters such as ponds and ponds with a minimum depth of around 30 centimeters are preferred as spawning biotopes . They are also happy to colonize so-called secondary biotopes such as gravel, sand or clay pits, but also extensively managed carp pond areas. A bank zone rich in vegetation, for example overgrown with swath cane , cattail or flood turf , meets the needs of the animals. More often, the spawning grounds are located near or even in the middle of cultivated arable land. Toad to hibernate dig up to a meter deep into the ground. Found cavities in the earth, such as mouse holes or mole passages, are preferred as winter quarters and redesigned according to one's own needs. The garlic toads usually avoid topsoils in the fen as well as in the floodplain and floodplain areas - unless the floodplain is interspersed with drifting sand dunes, geest islands or fluvial sand deposits. This is the case, for example, on the middle Elbe , where the species can even be found in very individual places. In optimal habitats, populations of several hundred or even over a thousand toads can sometimes be detected. In general, it can be assumed that the occurrence of the species is not yet fully known due to its hidden, inconspicuous way of life.
distribution
The distribution of the nominate form Pelobates fuscus fuscus mainly includes the lowlands of Central and Eastern Europe. The common spadefoot toad is a continental- pontic species. The westernmost occurrences are on the eastern border of France ( Rhine area ) and in the east of the Netherlands , the northernmost in Denmark and Estonia . In the east the area extends to Kazakhstan and in the south to Upper Italy , northern Serbia and Bulgaria . In Switzerland the species is considered to be extinct or at most has an uncertain status today, in Austria it is scattered outside the Alpine region or rarely found in eastern basin locations ( Styria , Upper Austria , Burgenland , Lower Austria , Vienna ).
The main areas of distribution in Germany are mainly in the lowlands of all north-eastern federal states (= north-eastern German lowlands) and in Lower Saxony (especially in the eastern half). In addition, there are certain accumulation of sites in northern Bavaria (especially: Franconian pond landscape) and in the Upper Rhine lowlands of Baden-Württemberg and southern Hesse . Otherwise, occurrences of this species are only found inconsistently in Germany or are completely absent, especially in the low mountain range regions dominated by weathered rocks.
Systematics
The common spadefoot toad and three other closely related species of the European sea-toed toad ( Pelobates ) usually form an independent family Pelobatidae in recent systematic reviews within the historically "medium-wide" development of the frog suborder Mesobatrachia (which some authors do not separate from the Archaeobatrachia ). Previously, the family Pelobatidae was further defined and also included the American paddock toads and the Asiatic toad frogs . Based on comparative DNA examinations, these are now each regarded as separate families and only grouped together taxonomically in the form of the superfamilies of the toad frogs (Pelobatoidea) and the Pelodytoidea (together with the mud divers ) . Other authors understand the families subsumed in Pelobatoidea and Pelodytoidea partly only as subfamilies.
The disjunct common spadefoot toad in the Italian Po Valley - earlier also in the extreme south of Switzerland - were temporarily treated as a separate subspecies Pelobates fuscus insubricus Cornalia, 1873 (Italian common spadefoot). However, this taxonomic status is now being questioned. In the main distribution area, a western and an eastern form of the common toad are also distinguished; some authors even give the eastern species its own category. At least it seems justified to differentiate this as a further subspecies from the nominate form. The eastern subspecies is called Pelobates fuscus vespertinus and occurs eastwards from eastern Ukraine and the European part of Russia.
Fossil evidence
The earliest fossil finds of the common toad in Central Europe date from the Upper Pliocene , about two million years ago. For the Ice Age ( Pleistocene ) there is widespread, but not very frequent evidence, mainly from areas with loess soils . Post-Ice Age warm phases were associated with intensive reforestation - in the case of the “steppe species” of the common garlic toad, this has even led to a decline in the meantime. Fossilized skeletal remains (but also "modern" for example, in Owls gewöllen be) quite well assign the spadefoot, because it has distinctive features in the bone structure. These include hump-like ossification of the skin on the roof of the skull and butterfly-shaped widenings and transverse processes on the lumbar vertebrae .
Hazard and protection
Garlic toads, like all Central European amphibians, suffer above all from the destruction or impairment of small bodies of water in the cultural landscape through the filling up or entry of garbage and environmental toxins. The flooding of fertilizers also pollutes many bodies of water and contributes to their premature silting up through eutrophication . However, in this respect the common garlic toads seem to be somewhat less sensitive than species such as the tree frog . If people put fish in small bodies of water that would not naturally occur there, this usually leads to a collapse of amphibian populations, as their spawn and larvae are eaten by most fish. In extensive carp pond farms with near-natural reed areas, garlic toads can survive quite well and also build up larger populations. This then sometimes happens to the annoyance of pond owners, who perceive the large tadpoles as a nuisance, perhaps also as a food competitor for their carp. Therefore, the completely harmless tadpoles, which feed on suspended organic matter and occasionally carrion and injured conspecifics, are still being combated.
The settlement of arable land is associated with considerable dangers for the common garlic toads. They can be injured or killed by agricultural machines during tillage, suffer lethal skin burns from artificial fertilizers, be affected when sewage sludge and liquid manure are spread and be poisoned by pesticides directly or indirectly via the food chain . In addition, the spadefoot toad is endangered by road traffic when migrating, for example if a road runs between the winter quarters and the spawning water.
While the populations of the species in area centers (such as in Germany, for example in Brandenburg and Saxony-Anhalt ) are often still assessed as safe, regional tendencies to decline are also noticeable, especially at the margins of distribution. In North Rhine-Westphalia the species is now considered "critically endangered".
Legal protection status (selection)
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Fauna-Flora-Habitat Directive (FFH-RL): Annex IV (species to be strictly protected)
- Subspecies P. f. insubricus : Appendix II (special protected areas are to be designated)
- Federal Nature Conservation Act (BNatSchG): strictly protected
National Red List classifications (selection)
- Red List Federal Republic of Germany: 3 - endangered
- Red list of Austria: EN (corresponds to: highly endangered)
- Red list of Switzerland: DD (data deficient = insufficient data situation)
nomenclature
Outdated scientific synonyms are Bufo fuscus Laurenti, 1768 (first description), Rana fusca Freyhans, 1779 and Bombina marmorata Koch, 1828. Johann Georg Wagler introduced the taxonomically correct scientific name Pelobates fuscus in 1830. This name was derived from the Greek ( ho pelos = mud, bainein = to go) and the Latin ( fuscus = dark brown, dark gray). Little to hardly used German-language trivial names are "garlic toad", "garlic frog toad", "brown toad frog", "land toad", "water toad" or "brown" or "marbled limber". In English the species is called "Common Spadefoot", in French "Pélobate brun", in Dutch "Knoflookpad", in Italian "Pelobate bruno", in Polish "Grzebiuszka ziemna".
Sources and further information
Individual evidence
- ↑ Karen Jahn: Observations on the burial depth of Pelobates fuscus during the spawning season. - Zeitschrift für Feldherpetologie 4 (1997, Issue 1), pp. 165-172. ISBN 3-933066-00-X
- ↑ for example: Viktor Wendland: The garlic toad (Pelobates fuscus) in Berlin and the surrounding area. - Milu, 2, pp. 332-339 (1967).
- ↑ Andreas Nöllert: The garlic toad. - Neue Brehm-Bücherei, Ziemsen-Verlag, Wittenberg, 2nd edition 1990, 103 pages ISBN 3-7403-0243-7 ; there also quotes from further references to this statement.
- ↑ Andreas Krone (ed.): The garlic toad (Pelobates fuscus) - distribution, biology, ecology and protection. RANA, special issue 5, Rangsdorf 2008, ISBN 978-3-9810058-6-8
- ↑ M. García-París, DR Buchholtz & G. Parra-Olea: Phylogenetic relationships of Pelobatoidea re-examined using mtDNA. - Molecular Phylogenetics and Evolution 28 (2003), pp. 12-23.
- ↑ Alain Dubois: Amphibia Mundi. 1.1. An ergotaxonomy of recent amphibians. - Alytes, Intern. Journal of Batrachology, Vol. 23, 2005, pp. 1-24.
- ↑ Kurt Grossenbacher: On the characterization and current situation of the Italian garlic toad, Pelobates fuscus insubricus. P. 17–28 in: Andreas Krone (Ed.): The garlic toad (Pelobates fuscus) - distribution, biology, ecology and protection. RANA, special issue 5, Rangsdorf 2008, ISBN 978-3-9810058-6-8
- ↑ Axel Kwet & Andreas Nöllert: The garlic toad - from Rösel von Rosenhof to the Froschlurch of the year 2007. P. 5–16 in: Andreas Krone (ed.): The garlic toad (Pelobates fuscus) - distribution, biology, ecology and protection. RANA, special issue 5, Rangsdorf 2008, ISBN 978-3-9810058-6-8
- ↑ Gottfried Böhme: On the historical development of the Herpetofaunen of Central Europe in the Ice Age (Quaternary). - In: Rainer Günther (Ed.): The amphibians and reptiles of Germany. - G. Fischer-Verlag, Jena, 1996, pp. 30-39. ISBN 3-437-35016-1
- ↑ Bernd Stöcklein: Investigations on amphibian populations on the edge of the Central Franconian pond landscape with special consideration of the common toad (Pelobates fuscus Laur.). - PhD. at the Univ. Erlangen-Nürnberg, 1980, 192 pp.
- ↑ For example: Christian Fischer: Population and area losses of natterjack toads (Bufo calamita) and garlic toads (Pelobates fuscus) in East Frisia (NW Lower Saxony). - Journal for field herpetology, Laurenti-Verlag, Bochum, vol. 6 (1999), pp. 95-101.
- ↑ Isabella Draber: Protection of the common garlic toad in Münsterland: Investigations on larvae and juveniles of the common garlic toad (Pelobates fuscus) as part of a Life + project in Münstrerland (North Rhine-Westphalia) . Osnabrück University of Applied Sciences, Osnabrück 2015.
- ↑ Garlic toad at www.wisia.de
- ↑ Federal Agency for Nature Conservation (ed.): Red list of endangered animals, plants and fungi in Germany 1: Vertebrates. Landwirtschaftsverlag, Münster 2009, ISBN 978-3-7843-5033-2
- ↑ Online overview at www.amphibienschutz.de
literature
- Andreas Krone (Ed.): The garlic toad (Pelobates fuscus) - distribution, biology, ecology and protection. RANA, special issue 5, Rangsdorf 2008, ISBN 978-3-9810058-6-8 .
- Norbert Menke, Christian Göcking & Arno Geiger: The garlic toad (Pelobates fuscus) - distribution, biology, ecology, protection strategies and breeding. LANUV-Fachberichte 75, 2016, 279 S. full text as pdf
- Robert Mertens: The amphibians and reptiles of the Rhine-Main area. - Verlag Kramer, Frankfurt / M., 1975.
- Burkhard Müller: Bio-acoustic and endocrinological investigations on the common toad Pelobates fuscus fuscus (Laurenti, 1768) (Salientia: Pelobatidae). In: Salamandra. Volume 20, 1984, pp. 121-142.
- Andreas Nöllert: The garlic toad. Neue Brehm-Bücherei, Ziemsen-Verlag, Wittenberg, 2nd edition 1990, 103 pages ISBN 3-7403-0243-7 .
- Andreas Nöllert, Rainer Günther: Garlic Toad - Pelobates fuscus (Laurenti, 1768). In: Rainer Günther (Ed.): The amphibians and reptiles of Germany. G. Fischer-Verlag, Jena / Stuttgart / Lübeck / Ulm 1996, ISBN 3-437-35016-1 , pp. 252-274.
- Peter Sacher: Multi-year observation of a population of the common spadefoot toad (Pelobates fuscus). - Hercynia NF Vol. 24 (1987), pp. 142-152.
- Hans Schneider: The mating calls of native frogs (Discoglossidae, Pelobatidae, Bufonidae, Hylidae). In: Journal for Morphology and Ecology of Animals. Volume 57, 1966, pp. 119-136.
- 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 . Audio samples 10–11.
- Ulrich Sinsch: Gravel as secondary habitats for threatened amphibians and reptiles. In: Salamandra, Volume 24, Issue 2/3, 1988, pp. 161-174.
Web links
- In case of danger: dig in or distribute headbuttons ( memento of March 11, 2008 in the Internet Archive ) at NABU .de
- Photos of the common garlic toad on www.herp.it (incl. Ssp. Insubricus )
- Common Garlic Toad (Pelobates fuscus) (Laurenti, 1768) ( Memento from April 4, 2008 in the Internet Archive )
- Pelobates fuscus in the endangered Red List species the IUCN 2006. Posted by: Kuzmin, S. et al , 2004. Retrieved on 10 May 2006..
Forest Lizard (2006) | Common Garlic Toad (2007) | European tree frog (2008) | Dice Snake (2009) | Pond newt (2010) | Wall Lizard (2011) | Common Toad (2012) | Smooth Snake (2013) | Yellow-bellied toad (2014) | European pond turtle (2015) | Fire Salamander (2016) | Slow Worm (2017) | Common Frog (2018) | Mountain Newt (2019)
