- Research Article
- Open Access
A global overview on the diet of the dice snake (Natrix tessellata) from a geographical perspective: foraging in atypical habitats and feeding spectrum widening helps colonisation and survival under suboptimal conditions for a piscivorous snake
© Weiperth et al.; licensee Springer. 2014
- Received: 29 January 2014
- Accepted: 4 July 2014
- Published: 23 July 2014
The dice snake (Natrix tessellata Laurenti, 1768) is generally considered to be a fully or partially piscivorous freshwater snake species. The aim of the study was to make the first global overview on the taxonomy and geographical distribution of the species based on own observations, available databases and the special literature.
Besides freshwaters, N. tessellata turned out to hunt also in marine and terrestrial habitats predating on at least 29 and 15 species, respectively. On the basis of our data and the literature altogether, 113 prey taxa, mostly fish, were listed but 20% of them were invertebrates, amphibians, reptiles and mammals. The importance of non-fish species in the diet was especially pronounced in deserts, high mountains and in dry Mediterranean areas. In spite of the wide feeding spectrum, only fish and amphibians were found to be predominant food items over the whole species' range. Fish dominated the catch of the dice snake in most quantitative studies, except one survey in Turkey, where the ratio of non-fish prey items was over 50%.
The global analysis of the diet of the dice snake revealed a feeding spectrum characteristically changing over the broad distribution area including non-fish prey as well as taxa from marine and terrestrial habitats. The analysis of the feeding spectrum separated four large geographical units with further distinctions in Central and Eastern Europe. Such diversity helps explain why this species was able to colonise a large and diverse Eurasian range.
- Natrix tessellata
- Feeding spectrum
The dice snake (Natrix tessellata Laurenti, 1768) is a Eurasian snake species ranging from Germany and Switzerland to China, Pakistan and Egypt (Gasc et al. ; Ibrahim ; Mebert et al. ) and is well adapted to the aquatic environment (Lahav and Dmi'el ; Nekrasova et al. ). It occurs in aquatic or marshy habitats, including brackish water (Gruschwitz et al. ; Khonjakina ; Tuniyev et al. ) occasionally even inhabiting cities such as Rome and Prague (Velenský et al. ; Vignoli et al. ). The distribution area of the dice snake is partly overlapped with two other aquatic Natrix species. The grass snake (Natrix natrix) lives in Eurasian habitats, often inhabiting similar areas with the dice snake (Gasc et al. ) while the viperine snake (Natrix maura) has sympatric populations in Switzerland and Italy with the dice snake (Metzger et al. ; Scali ). It is listed in Annex II of the Bern Convention () and it also appears in Annex IV of the Habitat Directive of the European Union () but due to its wide distribution and presumably large population size, it is categorised as least concern by IUCN (). However, it is considered to be threatened in a number of western and central European states, with low genetic variation in some populations (Gautschi et al. ; Guicking et al. ) and its world population was also assessed as declining (IUCN ). As such, conservation measures should still be undertaken for this species as habitat destruction, pollution, road traffic, collection and persecution are listed as possible threats.
The dice snake has a large distribution and it occurs in different habitats, which would imply the species can adapt well to local conditions presumably by adopting a wide feeding spectrum. However, it is generally considered to be a diurnal piscivorous snake (Gasc et al. ) despite information that shows the species also eats non-fish prey items such as amphibians and reptiles (see e.g. Beshkov and Dushkov ). A number of publications contain information on the food of the dice snake, with several focusing on local areas (e.g. Luiselli et al.  on Central Italy), but no global overview of the species' dietary preferences has been published.
The aim of this paper is to review the feeding spectrum of the dice snake over its global distribution by comparing the species' prey items in different countries and offer reasons for potential differences in prey item preference based on geography and habitat conditions.
Information was gathered from literature sources and personal observations on the diet of the dice snake from its whole range, i.e. from Switzerland in the west to Pakistan and China in the east, and from Germany in the north to Iran in the south. Information from papers only mentioning large, collective groups such as ‘insects’, ‘fish’ or ‘frogs’ as food items without giving species (or genus) level information is discussed in the article (e.g. Brecko et al. ) but was not included in the database, even if their addition would have added new items to the list such as mice (Wang et al. ) or shrews (Radovanović ). No time limit was applied; reports available from the first half of the twentieth century were also used. Besides published records and our observations, citizen science data were also collected by approaching internet databases for photographic evidence of dice snake predation on a given taxa (e.g. http://www.varangy.hu/, http://www.wuerfelnatter.de/). The distribution of different prey classes among different habitats was calculated and information on their frequency in the diet of the dice snake was also summarised. Species with no indication of frequency in the diet were listed under ‘no quantitative data’, whereas the following frequencies were listed when quantitative data was available: under 5% = rare; 5% to 20% = frequent; and >20% = common. Studies including quantitative data were also used for comparison after the relative abundance of prey taxa were calculated. Association analysis with the presence-absence data of the prey taxa of the dice snake were used in non-metric cluster analysis (Goodall ; Podani , ; Williams and Lambert ) to elucidate geographical differences among 18 countries, where appropriate information could be collected. Statistical analysis was made using SYN-TAX 2000 (Podani ). Results were plotted by MS Office 2010 and SYN-TAX 2000 (Podani ).
Species composition of prey taxa
Altogether, 113 animal taxa have been listed as prey for the dice snake belonging to three phyla: Mollusca, Arthropoda and Vertebrata. The ratio of classes among the taxa is 3% Gastropoda, 2% Insecta, 80% Pisces, 10% Amphibia, 3% Reptilia and 2% Mammalia. The complete list of prey species together with the indication of their frequency in the diet, country and habitat recorded is in Additional file 1.
Abundance of prey taxa in the diet of the dice snake
Geographical differences in the feeding spectrum of the dice snake
Data from 18 countries proved that the dice snake feeds on at least 113 prey taxa from six classes. Fish were the most important prey items; the importance of non-fish species in the diet was pronounced in deserts, high mountains and in dry Mediterranean areas. In spite of the wide feeding spectrum, only fish and amphibians were found to be predominant food items over the whole species' range.
Species composition of prey taxa
Due to its excellent swimming and diving abilities and fidelity to freshwater habitats, the dice snake is generally considered to be a piscivorous fish species (Gasc et al. , Kreiner ). However, the global feeding spectrum of the dice snake is surprisingly wide; it also includes a reasonable number of marine and terrestrial species (Figure 1), both fast- and slow-moving animals. For example, reptiles, especially lizards, have been found in the diet of the dice snake for more than 60 years (Göçmen et al. ), and slow aquatic and terrestrial invertebrates, snails and insects were also repeatedly reported (Additional file 1) (Bakiev et al. ; Göçmen et al. ; Wang et al. , ). A key factor determining the actual species composition is that according to current understanding of the species' habitat requirements over much of its range, the dice snake remains in the immediate vicinity of surface waters at a distance of less than 20 metres to the water edge during the active season (Conelli et al. ; Neumann and Mebert ; Velenský et al. ). As a result, the dice snake nearly exclusively feeds on aquatic and/or water-bound animals. The most important prey organisms are fish, especially in the European part of its distribution area, where over 75 species were recorded in the diet and 85% to 100% of food items belonged to this group. There is a clear relationship between fish species preyed upon and the size of water bodies. In seas, the dice snake may cover long distances up to several kilometres to hunt on benthic (Neogobius sp., Parablennius sp., Ponticola sp.) or open water marine (Clupeonella sp., Symphodus sp.,) fish species as it has been observed in the Caspian Sea (Tuniyev et al. ). In large lakes such as Lake Baćina (Hutinec and Mebert ), Lake Balaton (own unpublished data), Lake Prespa (Sterijovski et al. ), Lake Sinoe (Sloboda et al. ) and Lake Geneva (Metzger et al. ), the dice snake mostly eats benthic fish (Neogobius sp., Cottus gobio) and/or fish species hidden in aquatic vegetation stands (Cyprinidae sp., and e.g. Blennius fluviatilis, Lepomis gibbosus, Perca fluviatilis). In large rivers, densely vegetated water courses and lakes, they hunt fish (mainly Cyprinidae sp.), amphibian larvae and adults (mainly Pelophylax and Rana sp.) near the bank (Acipinar et al. ; Filippi et al. ; Gaebele et al. ; Luiselli et al. ; Vlček et al. ; Weiperth et al. ; Zimmerman and Fachbach ). In fishponds, the main prey species of the dice snake were juvenile fish from aquaculture and allochthonous fish species (Acipinar et al. ) with occasional predation on amphibians (tadpoles and froglets) such as in Jordanian fish ponds (Amr and Disi ) (Additional file 1). With decreasing waterbody size, the feeding spectrum of the dice snake considerably changes to include terrestrial species besides fish and amphibians common in the given area (Amr and Disi , ; Bakiev et al. ; Göçmen et al. ; Luiselli et al. ; Žagar et al. ) (Additional file 1). Populations in high mountains (over 1,000 m a.s.l.) may specialise on eating larval and adult amphibians (Cafuta and Krofel 2007; Frotzler et al. ; Tuniyev et al. ; Žagar et al. ) as predominant food. It can also be considerable in arid regions, where the dice snake often lives along temporary water bodies or fish ponds, where only a limited number of fish species are present (Amr and Disi ; Amr et al. ; Göçmen et al. ; Laňka ; Gruschwitz et al. ; Shehab et al. ). As young fish produced in fish farms can become an important element in the diet of the dice snake besides natural conditions, human activity may also influence the spread and survival of this snake (Acipinar et al. ; Göçmen et al. ).
Abundance of prey taxa in the diet of the dice snake
Several publications include estimates on the frequency of different prey organisms of the dice snake, including estimates for various habitats. Wang et al. (, ), for example, investigated 200 individuals and listed fish as the main food item in large, reed covered water bodies, insects, tadpoles and adult amphibians in temporarily water-covered rice paddies and connecting canals among them, and fish, tadpoles, insects and rodents (primarily mice) along streams in other agricultural areas in north-eastern China.
From the summary of detailed quantitative studies at half the sites only fish species were found in the dice snake (Figure 2); this result is characteristic for the species inhabiting permanent streams and large water bodies or rivers in Austria, Croatia, Romania and northern Turkey (Acipinar et al. ; Hutinec and Mebert ; Sloboda et al. ; Zimmerman and Fachbach ). Contradictory results were found on prey selection. For example, in Styrean waters, there was no complete overlap between the abundance of the different species in fish communities and in the diet of the dice snake (Zimmerman and Fachbach ), while in the Danube Delta, the number of snake-caught gobiid species was reflective of the abundance of the respective species in bottom habitats (Sloboda et al. ). Though the feeding spectrum of the studies was wide, fish were also the most abundant prey species at the other sites including the Mediterranean (Bakiev et al. ; Filippi et al. ; Luiselli et al. ). In one case, however, other food items (insects, amphibians, reptiles and mammals) in total were more numerous than fish (Göçmen et al. ). Though the number of these studies is limited, they support the general conclusion that over much of its range, the dice snake primarily feeds on fish, while in arid areas (see also Frotzler et al. ) and, according to Cafuta and Krofel (2007), also in high mountains, its diet may shift towards amphibians and other prey items.
Geographical differences in the feeding spectrum of the dice snake
The feeding spectrum of the dice snake differs among different regions, the analysis of the results revealed four main groups (Figure 4). The group separated most from other branches includes Asian countries with dice snake populations in highly arid regions (Iran, Syria, Jordan). The list of prey species in these countries is short, with snakes predominantly feeding on fish and amphibians from permanent rivers and alien fish species kept in fish farms (Amr and Disi ; Amr et al. ; Shehab et al. ). Fish ponds also function as refugia over the driest periods but at the same time the dice snake is under great predation pressure there due to the large number of aquatic birds present (Amr and Disi ; Bakaloudis et al. ; Shehab et al. ).
The second group in the cluster includes countries with the highest number of Ponto-Caspian gobiid species (e.g. Neogobius, Parablennius, Ponticola). Marine fish species are also common and amphibian predation was recorded in all countries of the Romanian-Bulgarian-Georgian-Azerbaijani branch (Additional file 1) as well (Fautz ; Schülter ; Sloboda et al. ; Tuniyev et al. ).
Central and Eastern European countries formed a common group with Russia. There are several fish with very large distribution areas among the prey species there such as Alburnus alburnus, Squalius cephalus, Rutilus rutilus, Cyprinus carpio, Gobio gobio, Perca fluviatilis (Additional file 1). The Czech - Polish branch include countries with limited amphibian consumption (Rehak ; Švab ; Vlček et al. ), while high mountain populations (Austria, Switzerland, Slovenia) feeding on locally characteristic fish species and also on amphibians are on another sub-branch.
Countries with Mediterranean climate (Croatia, Italy, Turkey) form the final group with freshwater tolerating marine fish species and cosmopolitan fish species in the diet of the dice snake. This area is characterised with the most diverse feeding spectrum including snails, insects, reptiles and mammals (Additional file 1, Figure 3) related to the drying out of many water bodies during summer. During extremely hot summers, the dice snake was also observed to hunt at night, also far away from surface waters, which furthers the potential feeding spectrum of this snake (see e.g. Moller , who observed over a period of several weeks a large dice snake which ‘unusually’ hunted geckos at night).
Snakes have strikingly different feeding spectra ranging from strictly egg-eating species with limited distribution (see e.g. Dandge ) to generalist species living over large areas (Gregory and Isaac ). The dice snake is present in over 20 countries on three continents, which is, unlike what has been suggested earlier on the basis of observations from the western-central part of its distribution area, partly the result of its generalist feeding strategy leading to a good adaptive ability if the potential prey spectrum changes (Acipinar et al. ; Reshetnikov et al. ). It is also supported by its anatomy enabling this snake to hunt effectively in both aquatic and terrestrial environments (Bilcke et al. , ; Brecko et al. ; Ghira et al. ; Wassenbergh et al. ). As such, a wide feeding spectrum had been expected as a result of this study. On the one hand, the global comparison supported the assumption that the dice snake is a piscivorous snake; it stressed the importance of fish in the diet. On the other hand, it revealed the complexity of the feeding spectrum including invertebrates, amphibians, reptiles and mammals and good adaptability to the effect of climate, altitude and even human activity, which explains why this species could colonise a large and diverse Eurasian range. Also, it elucidated the ability of this snake to survive under suboptimal conditions at the edge of its distribution, enter atypical habitats in natural areas such as high mountains as well as in human-dominated landscapes, such as rice paddies by shifting its diet even towards terrestrial or marine prey species.
Abiotic environmental parameters are known to have an important, but limited power in determining reptile distributions on a larger scale; other factors such as resources are also important (Guisan and Hofer ). As far as feeding spectra are concerned, the dice snake was considered to be in an intermediate position among the three Natrix species inhabiting the Palearctic. In a comparative study with the closely related grass snake (Natrix natrix), Luiselli and Rugiero () found the dice snake to have a narrower feeding spectrum than the grass snake, which also has a broader distribution (Gasc et al. ). The latter species more plastically changing its diet and populations near to each other within relatively short distances may specialise on different food (Luiselli et al. ). What is more, the presence of the dice snake did not have any apparent effect on the food types eaten by grass snakes because grass snakes consumed fish when sympatric with N. tessellata (Luiselli et al. ). The diet of the third species, the viperine snake, Natrix maura, shows a considerable overlap with that of the dice snake but with some exceptions (see e.g. the observations of Scali, ), and due to other factors as fertility and size, the dice snake is able to outcompete the viperine snake (Metzger et al. ).
This study altered the hypothesis that the diet of the dice snake consists of fish from freshwater habitats as indicated by several authors. While this is still the majority of the diet, the feeding spectrum characteristically changed over the broad distribution of the species including non-fish prey as well as taxa from marine and terrestrial habitats as well. The dice snake is rather opportunistic in preying on fish, in total it was proved to eat at least 87 fish taxa, but it also takes other prey, primarily amphibians, when fishes are regionally not constantly available. The analysis of the feeding spectrum separated four large geographical units with further distinctions in Central and Eastern Europe. Such diversity helps explain why this species was able to colonise a large and diverse Eurasian range.
The authors thank Andrew Hamer and the anonymous reviewers for improving an earlier version of the manuscript.
- Acipinar H, Gaygusuz O, Tarkan AS, Gürsoy CAZ: Presence of an invasive fish species, Carassius gibelio (Bloch, 1782) in the diet of dice snake, Natrix tessellata (Laurenti, 1768). J Fish Aquat Sci 2006,1(2):213–217. 10.3923/jfas.2006.213.217View ArticleGoogle Scholar
- Ahmadzadeh F, Konrad M, Saeedeh A, Elham R, Goli LA, Böhme W: Ecological and biological comparison of three populations of dice snakes ( Natrix tessellata) from the southern Caspian Sea coast, Iran. Mertensiella 2011, 18: 403–413.Google Scholar
- Amr ZS, Disi AM: Diet of some snakes from Jordan. Amphibia-Reptilia 1998, 19: 436–439. 10.1163/156853898X00106View ArticleGoogle Scholar
- Amr ZS, Disi AM: Systematics, distribution and ecology of the snakes of Jordan. Vertebr Zool 2011,61(2):179–266.Google Scholar
- Amr ZS, Mebert K, Hamidan N, Baker MA, Disi A: Ecology and conservation of the dice snake ( Natrix tessellata ) in Jordan. Mertensiella 2011, 18: 393–400.Google Scholar
- Bakaloudis DE, Vlachost CG, Holloway GJ: Habitat use by short-toed eagles Circaetus gallicus and their reptilian prey during the breeding season in Dadia Forest (north-eastern Greece). J Appl Ecol 1998, 35: 821–828. 10.1111/j.1365-2664.1998.tb00001.xView ArticleGoogle Scholar
- Bakiev A, Kirillov AA, Mebert K: Diet and parasitic helminths of dice snakes from the Volga Basin, Russia. Mertensiella 2011, 18: 325–329.Google Scholar
- Bern Convention (1999) Law on ratification of convention of conservation of free living European flora and fauna and their natural habitats (Ur. l. RS 17/99). ᅟ, ᅟGoogle Scholar
- Beshkov VA, Dushkov DT: Materials on the batrachophagy and herpetophagy of snakes in Bulgaria. Ekologyia (Sofia) 1981, 9: 43–50.Google Scholar
- Bilcke J, Herrel A, Damme RV: Correlated evolution of aquatic prey-capture strategies in European and American natricine snakes. Biol J Linn Soc 2006, 88: 73–83. 10.1111/j.1095-8312.2006.00608.xView ArticleGoogle Scholar
- Bilcke J, Herrel A, Aerts P: Effect of prey- and predator size on the capture success of an aquatic snake. Belgian J Zool 2007,137(2):191–195.Google Scholar
- Brecko J, Herrel A, Damme RV: The relationships between head morphology and diet in the dice snake ( Natrix tessellata ). Mertensiella 2011, 18: 20–29.Google Scholar
- Bressi N: Erpetofauna delle foci del Fiume Isonzo, e note eco-etologiche sull’erpetofauna dell’ isola della Cona (Friuli-Venezia Giulia, Italia Nord-orientale). Atti Mus Civ Stor Nat Trieste 1995, 46: 179–229.Google Scholar
- Cafuta V, Krofel M, (2007) Report on field work of the group for reptiles. In: Stanković, et al. (ed) Biology student research camp Lovrenc na Pohorju, (2005) Biology Student Society. Ljubljana, pp ᅟ:81–88Google Scholar
- Carlsson M, Karvemo S, Tudor M, Sloboda M, Mihalca AD, Ghira I, Bel L, Modry D: Monitoring a large population of dice snakes at Lake Sinoe in Dobrogea, Romania. Mertensiella 2011, 18: 237–244.Google Scholar
- Conelli AE, Nembrini M, Mebert K: Different habitat use of dice snakes, N atrix tessellata , among three populations in Canton Ticino, Switzerland – a radiotelemetry study. Mertensiella 2011, 18: 100–106.Google Scholar
- Dandge PH: Food and feeding habits of Elachistodon westermanni Reinhardt, 1863. Hamadryad 2008,32(1):86–88.Google Scholar
- Council Directive 92/43/EEC of 21. May 1992 on the Conservation of Natural Habitats and of Wild Fauna and Flora (the Habitats Directive), ᅟ; 1992.Google Scholar
- Fautz R: The flounder, Platichthys flesus , as prey of the dice snake, Natrix tessellata , in Turkey. Zool Middle East 1986, 1: 118–119. 10.1080/09397140.1986.10637532View ArticleGoogle Scholar
- Filippi E, Capula M, Luiselli L, Agrimi U: The prey spectrum of Natrix natrix (Linnaeus, 1758) and Natrix tessellata (Laurenti, 1768) in sympatric populations. Herpetozoa 1996,8(3/4):155–164.Google Scholar
- Frotzler N, Davitashvili N, Mebert K: Distribution of the dice snake ( Natrix tessellata ) in Georgia (Transcaucasia) and comparative notes on the genus Natrix . Mertensiella 2011, 18: 357–364.Google Scholar
- Gaebele T, Potyó I, Weiperth A, Guti G, Puky M: Abundant prey or optimal microhabitat? Natrix tessellata stays hidden in safe areas in a diverse floodplain along the Danube at Göd, Hungary. North-Western J Zool 2013,9(2):374–382.Google Scholar
- Atlas of Amphibians and Reptiles in Europe. Collection Patrimoines Naturels 29. Societas Europaea Herpetologica, Muséum National d’Histoire Naturelle & Service du Patrimoine Naturel. Paris, France; 1997.Google Scholar
- Gautschi B, Widmer A, Joshi J, Koella JC: Increased frequency of scale anomalies and loss of genetic variation in serially bottlenecked populations of the dice snake, Natrix tessellata . Conserv Genet 2002,3(3):235–245. 10.1023/A:1019924514465View ArticleGoogle Scholar
- Ghira I, Butănescu D, Marosi B: Feeding behavior of the dice snake ( Natrix tessellata ). Herpetologica Romanica 2009, 3: 1–7.Google Scholar
- Göçmen B, Çiçek K, Yildiz MZ, Atatur MK, Dinçaslan YE, Mebert K: A preliminary study on the feeding biology of the dice snake, Natrix tessellata, in Turkey. Mertensiella 2011, 18: 365–369.Google Scholar
- Goodall DW: Objective methods for the classification of vegetation I. The use of positive interspecific correlation. Aust J Bot 1953, 1: 39–63.Google Scholar
- Gregory PT, Isaac LA: Food habits of the grass snake in southeastern England: is Natrix natrix a generalist predator? J Herpetol 2004,38(1):88–95. 10.1670/87-03AView ArticleGoogle Scholar
- Gruschwitz M, Lenz S, Mebert K, Laňka V: Natrix tessellata (Laurenti, 1768) - Wurfelnatter. In Bohme W (ed) Handbuch der Reptilien und Amphibien Europas. Bd. 3/Schlangen II, AULA-Verlag, Wiesbaden, Germany; 1999:581–644.Google Scholar
- Guicking D, Herzberg A, Wink M: Population genetics of the dice snake ( Natrix tessellata ) in Germany: implications for conservation. Salamandra 2004,40(43/4):217–234.Google Scholar
- Guisan A, Hofer U: Predicting reptile distributions at the mesoscale: relation to climate and topography. Journal of Biogeography 2003, 30: 1233–1243. 10.1046/j.1365-2699.2003.00914.xView ArticleGoogle Scholar
- Hutinec JB, Mebert K: Ecological partitioning between dice snakes ( Natrix tessellata ) and grass snakes ( Natrix natrix ) in southern Croatia. Mertensiella 2011, 18: 225–233.Google Scholar
- Ibrahim AA: New records of the dice snake, Natrix tessellata , in the Suez Canal zone and Sinai. Amphibian Reptile Conservation 2012,6(2):2–4.Google Scholar
- IUCN Red list of threatened species. Version 2012.2, ᅟ; 2012.Google Scholar
- Kammel W, Mebert K: Effects of rehabilitation of the polluted river system Mur in Styria, Austria, and construction of hydroelectric power plants on fish fauna and distribution of the dice snake. Mertensiella 2011, 18: 188–195.Google Scholar
- Karvemo S, Carlsson M, Tudor M, Sloboda M, Mihalca AD, Ghiram I, Bel L, Modry D: Gender differences in seasonal movement of dice snakes in Histria, southeastern Romania. Mertensiella 2011, 18: 245–254.Google Scholar
- Khonjakina ZP: Materialy po rasprostraneniju i biologii vodjanogo uzha v Dagestane. Spornik nauchnykh soobscheniy kaf. zool. DGU Сб, Makhachkala; 1969.Google Scholar
- Kireev VA: Fauna of Kalmykia – amphibians and reptiles. Kalmykia Publisher, Elista, Russia; 1983.Google Scholar
- Krasawtzev BA: O pitanii nekotorykh zmej v Dagestane. Izv. 1 i 2 Severo Kavkazskogo Ped, Instituta. Bd. 2/P, Ordzhonikidze; 221.Google Scholar
- Kreiner G: The snakes of Europe: all species from west of the Caucasus Mountains. Frankfurt am Main, Edition Chimaria; 2007.Google Scholar
- Lahav S, Dmi'el R: Skin resistance to water loss in colubrid snakes: ecological and taxonomical correlations. Ecoscience 1996,3(2):135–139.Google Scholar
- Laňka V: Variabilitat und Biologie der Würfelnatter ( Natrix tessellata ). Acta Universitatis Carol Biol 1978, 1975–1976: 167–207.Google Scholar
- Luiselli L, Rugiero L: Food niche partitioning by water snakes (Genus Natrix ) at a freshwater environment in Central Italy. Journal of Freshwater Ecology 1991,6(4):439–444. 10.1080/02705060.1991.9665323View ArticleGoogle Scholar
- Luiselli L, Filippi E, Capulla M: Geographical variation in diet composition of the grass snake ( Natrix natrix ) along the mainland and an island in Italy: the effect of habitat type and interference with potential competitors. The Herpetological Journal 2005,15(4):221–230.Google Scholar
- Luiselli L, Capizzi D, Filippi E, Anibaldi C, Rugiero L, Capula M: Comparative diets of three populations of an aquatic snake ( Natrix tessellata , Colubridae) from Mediterranean streams with different hydric regimes. Copeia 2007, 2: 426–435. doi:10.1643/0045–8511(2007)7[426:CDOTPO]2.0.CO;2 10.1643/0045-8511(2007)7[426:CDOTPO]2.0.CO;2View ArticleGoogle Scholar
- Märtson M, Taittonen M, Alanen M, Reunanen M: Vipera berus adder bite in the water, complicated by rapid shock. A case history. Eur J Pediatr Surg 2001, 5: 358–360. 10.1055/s-2001-18545View ArticleGoogle Scholar
- Mebert K, Conelli AE, Nembrini M, Schmidt BR: Monitoring and assessment of the distribution of the dice snake in Ticino, southern Switzerland. Mertensiella 2011, 18: 117–130.Google Scholar
- Mebert K, Masroor R, Chaudhry MJI: The dice snake, Natrix tessellata (Serpentes: Colubridae) in Pakistan: analysis of its range limited to few valleys in the Western Karakoram. Pakistan J Zool 2013,45(2):395–410.Google Scholar
- Metzger C, Christe P, Ursenbacher S: Diet variability of two convergent natricine colubrids in an invasive-native interaction. Mertensiella 2011, 18: 86–93.Google Scholar
- Moller T: Zur Herpetofauna im Suden Bulgariens. Aquar. Terrar. Zeitschrift Stuttgart 1990,43(7):431–434.Google Scholar
- Musilová R, Zavadil V: Užovka podplamatá v České republice. Zoo Rep Mag Pro Přátala Zoo Brno 2011, 1: 1–4.Google Scholar
- Nekrasova OD, Gavris GG, Kuybida VV: Changes in the northern border of the home range of the dice snake, Natrix tessellata (Reptilia, Comunridae), in the Dnipro Basin (Ukraine). Vestnik Zool 2013,47(5):67–71.Google Scholar
- Neumann C, Mebert K: Migration behavior of endangered dice snakes ( Natrix tessellata ) at the River Nahe, Germany. Mertensiella 2011, 18: 39–48.Google Scholar
- Podani J: Bevezetés a többváltozós biológiai adatfeldolgozás rejtelmeibe. Scientia Kiadó, Budapest; 1997.Google Scholar
- Podani J: SYN-TAX 2000. Computer program for data analysis in ecology and systematics. Scientia Kiadó, Budapest; 2001.Google Scholar
- Radovanović M: Vodozemci i gmizavci naše zemlje. Naučna Knjiga, Beograd, Serbia; 1951.Google Scholar
- Rehak I: Natrix tessellata (Laurenti, 1768). Baruš V, Oliva O (eds) Užovka podplamata, Fauna ČSFR. Plazi-Reptilia svazek 26, Academia, Praha; 1992.Google Scholar
- Reshetnikov AN, Sokolov SG, Chikhlyaev IV, Fayzulin AI, Kirillov AA, Kuzovenko AK, Protasova EN, Skomorokhov MO: Direct and indirect interactions between an invasive alien fish ( Perccottus glenii ) and two native semi-aquatic snakes. Copeia 2013,2013(1):103–110. 10.1643/CE-12-007View ArticleGoogle Scholar
- Scali S: Ecological comparison of the dice snake ( Natrix tessellata ) and the viperine snake ( Natrix maura ) in Northern Italy. Mertensiella 2011, 18: 131–144.Google Scholar
- Schiemenz H: Die Kreuzotter. Die Neue Brehm Bucherei. A, Ziemens Verlag, Wittenberg, Lutherstadt, Germany; 1987.Google Scholar
- Schülter U: Die Herpetofauna der bulgarischen Schwarzmeerküste - Teil 3: Schlangen. Elaphe 2006,14(2):59–66.Google Scholar
- Shehab AH, Masri AA, Zuhair S, Amr ZS: The dice snake ( Natrix tessellata ) in Syria: distribution, trade and conservation. Mertensiella 2011, 18: 388–392.Google Scholar
- Sloboda M, Mihalca AD, Falka I, Petrželková KJ, Carlsson M, Ghira I, Modry D: Are gobiid fish more susceptible to predation if parasitized by Eustrongylides excisus ? An answer from robbed snakes. Ecol Restor 2010, 25: 469–473. 10.1007/s11284-009-0676-4View ArticleGoogle Scholar
- Sterijovski B, Ajtić R, Tomović L, Djordjević S, Djurakić M, Golubović A, Isailović CJ, Ballouard JM, Desmont D, Groumpf F, Bonnet X: Natrix tessellata on Golem Grad, FYR of Macedonia: a natural fortress shelters a prosperous snake population. Mertensiella 2011, 18: 298–301.Google Scholar
- Švab M: Ekologie Užovky Podplamate (Natrix tessellata) ve Střednich Čechach. Zoologie, Praha, Czech Republic, M.S. Kat; 2003.Google Scholar
- Tuniyev B, Tuniyev S, Kirschey T, Mebert K: Notes on the dice snake, Natrix tessellata, from the Caucasian Isthmus. Mertensiella 2011, 18: 343–356.Google Scholar
- Velenský M, Velenský P, Mebert K: Ecology and ethology of dice snakes ( Natrix tessellata ) in the city district Troja, Prague. Mertensiella 2011, 18: 157–175.Google Scholar
- Velikov I: Dice snake feeds on spiny invasive fish. Mertensiella 2011, 18: 447.Google Scholar
- Vignoli L, Mocaer I, Luiselli L, Bologna MA: Can a large metropolis sustain complex herpetofauna communities? An analysis of the suitability of green space fragments in Rome. Anim Conserv 2009, 12: 456–466. 10.1111/j.1469-1795.2009.00273.xView ArticleGoogle Scholar
- Vlček P, Najbar B, Jablonski D: First records of the dice snake ( Natrix tessellata ) from the North-Eastern part of the Czech Republic and Poland. Herpetology Notes 2010, 3: 23–26.Google Scholar
- Wang G, Qi W, Ma M, Wang H, Lei J: Population ecology of Natrix tessellata (Laurenti, 1768) (in Chinese). Arid Zone Res 1987,28(2):35–40.Google Scholar
- Wang G, Fan Y, Zhai RX: Distribution and ecology of snakes in Xinjiang (in Chinese). Arid Zone Res 2005,22(2):181–185.Google Scholar
- Wassenbergh SW, Brecko J, Aerts P, Stouten I, Vanheusden G, Camps A, Damme RV, Herrel A: Hydrodynamic constraints on prey-capture performance in forward-striking snakes. J R Soc Interface 2010,2010(7):773–785. 10.1098/rsif.2009.0385View ArticleGoogle Scholar
- Weiperth A, Potyó I, Puky M: Diet composition of the dice snake ( Natrix tessellata Laurenti, 1768) (Reptilia: Columbridae) in the Danube River Catchment area. Acta Zool Bulg Suppl 2014, 7: 51–56.Google Scholar
- Williams WL, Lambert JM: Multivariate methods in plant ecology. I. Association analysis in plant community. J Ecol 1960, 47: 83–101.Google Scholar
- Žagar A, Krofel M, Govedič M, Mebert K: Distribution and habitat use of dice snakes, Natrix tessellata , in Slovenia. Mertensiella 2011, 18: 193–202.Google Scholar
- Zimmerman P, Fachbach G: Verbreitung und Biologie der Würfelnatter, Natrix tessellata tessellata (Laurenti, 1768), in der Steiermark (Österreich). Herpetozoa 1996,8(3/4):99–124.Google Scholar
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