EUROPEAN JOURNAL OF ECOLOGY EJE 2016, 2(2): 44-63, doi: 10.1515/eje-2016-0015 Is new spread of the European beaver in Pannonian basin an evidence of the species recovery? 1* 2, 3 4 5 6 1Institute of Biology and Alexander Čanády , Peter Krišovský Bálint Bajomi , Attila Huber , Dávid Czabán , Milan Olekšák Ecology, Faculty of Sci- ence, P.J. Šafárik Univer- sity, Šrobárova 2, SK-041 54 Košice, Slovakia ABSTRACT Corresponding author, Abstract: During fieldwork from 6 June to 20 July 2016, the first records of the European beaver (Castor fiber) E-mail: alexander. [email protected] in south-eastern Slovakia were made. Beavers are mainly nocturnal animals, and as such, they are rarely ob- served; therefore, our observations were based on searching for beaver presence signs: damaged trees, dams, 2 The East Slovak Mu- signs of food consumption (chewed/felled trees) and footprints in the mud. The southern part of the Košická seum Košice, Námestie kotlina basin, from the city of Košice down to the state border and the surrounding villages in Hungary, was Maratónu mieru 2, SK- 040 01 Košice, Slovakia checked. We found two beaver locations via feeding signs in the vicinity of the Slovakia–Hungary state border, at the villages of Milhosť (Miglécnémeti) and Buzica (Buzita), in Slovakia. According to our calculations, the pre- 3 Independent scholar, sent total beaver population in Hungary is between 4,000 and 5,000 and 14,600–18,300 beavers with potential H-1118, Tűzkő utca 1., support. For Slovakia, we estimated the potential population size to be 7,700–9,600. Our findings in northern VI. em. 19., Budapest, Hungary Pannonian lowland (Slovakia–Hungary border) are an important evidence of beaver expansion. Although we don’t know the exact origin of investigated population, these new records indicate the possibility of merging the 4 Aggtelek National Park populations of different origin, which could enable gene flow and increase the genetic diversity. This could lead Directorate, H-3758 to improved recovery of species and its stabilisation in nature. However, it is necessary to carry out a detailed Jósvafő, Tengerszem oldal 1., Hungary investigation of the presence of beaver in these regions in future. 5 Department of Wildlife Biology and Ethology, Kaposvár University, KEYWORDS H-7400, Kaposvár, Guba Sándor u, Hungary Castor fiber, south-eastern Slovakia, Hungary, migration, first record, rewilding, comeback, spread © 2016 A. Čanády et al. 6 Slovak Karst National This is an open access article distributed under the Creative Commons Attribution-NonCommercial-NoDerivs license Park Administration, Biely kaštieľ 188, SK-049 51 Brzotín, Slovakia INTRODUCTION shown that the beaver is currently established in all countries The European beaver (Castor fiber) was a common species in within the species’ former natural range in continental Europe, the rivers of Europe and northern and eastern Asia until the with the exceptions of Portugal, Italy and the southern Balkans. late 19th century (Nolet & Rosell 1998; Halley & Rosell 2002, The continuous population ranges from Germany through Po- 2003; Halley et al. 2012). By the beginning of the 20th centu- land, the Baltic States, Belarus and Ukraine to central Siberia in ry, the global population had been reduced to eight isolated the Russian Federation. A second large disjunctive population populations: in the Rhone Delta (France), on the middle Elbe and smaller scattered isolated populations through the rest of (Germany), in south Norway (Telemark), in the Dnieper river mainland Europe are located in Norway and Sweden. Isolated system in Belarus and the Ukraine, in the Voronezh-Don-sys- reintroduced populations have also been recorded in distinct tem (Russia), in the Konda and Sosva rivers (East Ural region, locations outside the former Soviet Union, for example, in Po- Russia), on the upper Yenisei and Azas rivers (Russia, Tuva Re- land (Dzięciołowski & Gozdziewski 1999). public) and in the Bulgan river (Mongolia/China). Nevertheless, In Slovakia, beaver was exterminated during 19th in recent decades, protection, natural spreading and reintro- century, mainly because of hunting for meat, fur and casto- ductions have resulted in a rapid recovery in the numbers and reum with the shot in 1858 at Žitný Ostrov. The species be- range of this species, particularly in continental Europe and, gan to gradually spread again in 1977 from Austria and since recently, also in Great Britain (Halley & Rosell 2002; Halley et 1981 from Poland (Valachovič 2012). The author summarised European Journal of Ecology European Journal of Ecology al. 2012; Stringer & Gaywood 2016). Halley et al. (2012) have all published and unpublished data and estimated that the oc- EUROPEAN JOURNAL OF ECOLOGY currence of beaver has been recorded in about 11.6% of the consumption (chewed/felled trees), footprints in the mud, and territory of Slovakia. This is very important because the beaver so on along the Torysa and Hornád (Hernád in Hungarian) riv- was absent from Slovakia for 150 years. Since 1977, the south- ers and its tributaries in the period from 6 June to 20 July 2016. western population has grown dynamically in the catchments The research was done by walking next to the water. First, the of the Morava and Danube rivers. In contrast, the beaver only southern part of the Košická kotlina basin, away from the city of appeared more recently in north-eastern Slovakia in 1981. Košice in the direction of the Hungarian border, was examined. Valachovič (2012) summarised several older findings from east- In addition to the direct search, we also had conversations with ern Slovakia and showed the first occurrence on the Ondava local residents. Overall, 18 municipalities and their surround- river; then on the Poprad, Topľa, Dunajec and Cirocha rivers, ings were checked (Belža, Čaňa, Geča, Kokšov-Bakša, Nižná and, finally, on the upper part of the Laborec river. All observa- Myšľa, Krásna nad Hornádom, Bohdanovce, Košická Polianka, tions confirmed that the species predominantly inhabits low- Sady nad Torysou, Olšovany, Nižná Hutka, Vyšná Hutka, Ždaňa, lands in the region. Moreover, the beaver occupies about 30% Trstené pri Hornáde, Perín-Chym, Buzica, Komárovce and Veľká of the potentially suitable parts of Slovak territory (about 56% Ida). We also checked the surroundings of watercourses in of Slovakia’s entire territory), and restoration of the population nine Hungarian villages (Abaújvár, Telkibánya, Bózsva, Pálháza, runs in two phases (Valachovič 2012; Halley et al. 2012). The Mikóháza, Tornyosnémeti, Hidasnémeti, Hernádszurdok and first phase includes rapid growth of newly colonised territories, Zsujta). up to the nearest barrier. The second phase, which began ap- In addition to direct searches for the beaver pres- proximately in 1999, includes a rise in the population size, dur- ence signs, we tried to determine the number of individuals ing which the beavers increase their population by also colonis- by the number of bitten or gnawed trees (Dyakov 1975). This ing suboptimal localities. In this phase, the population size has method is based on the total number of completely (felled) and started to grow exponentially. incompletely gnawed trees and their dimensions (diameter of The history of extinction and re-settlement was ob- the trunk) and then calculating the index which determine the served in Hungary as well. The distribution in Hungary shows approximate number of individuals. Finally, we have estimated that the beavers became extinct in 1865, mostly because of potential total beaver population in Hungary and Slovakia from overhunting, and were absent from Hungarian fauna for 130 beaver families, that is, territories. years. They appeared again in the Szigetköz area (Bajomi 2011a, b). Similarly, several authors (Boszér 2001; Bera 2007; Bera & Gruber 2007; Bajomi 2011a, b; Bajomi et al. 2016) showed that 2. RESULTS AND DISCUSSION these animals probably wandered here from a population suc- From all the above-mentioned and controlled areas in Slovakia, cessfully established by reintroduction in Austria. In 1988, bea- only 22 damaged purple willow (Salix purpurea) trees from vers were also found near Lake Tisza. This small population was the autumn and winter seasons were found with completely later augmented with seven more animals by the staff of the gnawed trunks on the shore of a lake formed by a former gravel Hortobágy National Park Directorate. Later, authorities realised quarry near Milhosť (Figures 1a, b and 2). We used the method that the reintroduced specimens were actually Canadian bea- of Dyakov (1975) to estimate the population size of beaver and vers (Castor canadensis). For this reason, the last living animals confirmed the presence of approximately 3 individuals, which (some had already died) were trapped by park rangers. More- is consistent with the presence of one family (Table 1). More- over, between 1996 and 2008, more than 200 beavers were over, gnawed trees, including five gnawed willows (all were reintroduced in the areas of Gemenc and Hanság and in area 16.0 cm in diameter), were also found at the confluence of two next to the Tisza and Dráva rivers. Most of these beavers came streams, Szartos-patak stream and Sokoliansky potok stream from Bavaria and Germany, and some animals from Austria. (Figure 1b). This record is very important because it is prob- In the present study, we provide the first knowledge ably the gateway to the water surface of the lake or forms a of the occurrence of the species in south-eastern Slovakia, on new migration route northwards or southwards. The damaged the Slovakia–Hungary state border. We discuss whether these trees were not only from the autumn and winter seasons, but occurrences at the state border represent the beginning of the we also found freshly gnawed willow branches, which is the spread with potential gene flow, for example, mixing of two evidence for the survival of beavers in the studied area. These populations between Hungary and Slovakia.