Ábrahám Levente (szerk.): Válogatott tanulmányok V. - Natura Somogyiensis 17. (Kaposvár, 2010)
LANSZKI, J., MÓROCZ, A. & CONROY, J. W. H.: A vidra (Lutra lutra) kora tavaszi táplálék-összetétele a Gemenci Tájegység (Duna-Dráva Nemzeti Park, Magyarország) természetes élőhelyein
322 NATURA SOMOGYIENSIS 1997, ROCHE 1998, KLOSKOWSKI 1999, TAASTROM & JACOBSEN 1999, RUIZ-OLMO et al. 2001, COPP & ROCHE 2003, REMONTI et al. 2008). In contrast with these, some studies performed along productive salmon rivers in Scotland showed that, at least in some times of the year, otters consumed primarily large-sized catadromous spawning fish, which were readily available at that time ( CARSS et al. 1990). A significant difference was found in the distribution of fish guilds preyed upon by otters living in the different areas (x 2i2 = 402.90, P<0.001). However, the most frequent fish prey were eurytopic species (>69%, Fig. 4a), but consumption of stagnophilic fish species was also considerable in two areas (HK: 9.1% and ND: 7.2%, first cluster on Fig. 4b). There was also one area where consumption of reophilic fish species was considerable (HS: 24.5%) and in this it differed from all other areas. Despite the proximity of the Danube River, otters consumed reophilic fish in relatively low ratios, as was also found on oxbow lakes of the Drava River (LANSZKI & SALLAI 2006) and, depending on area, consumed considerable numbers of euritopic fish. Significant area-dependent difference (x 2 5 = 52.05, P<0.001) was found in the distribution of fish origin (Fig. 5a). Consumption of native and non-native fish species was approximately 50-50% in three areas (HS, ND és BD, first cluster on Fig. 5b), while in two areas, consumption of non-native fish was greatest (TD: 86.0% and HK: 73.8%, second cluster in Fig. 5b) and in one area the consumption of native fish (DD: 98.0%, third cluster on Fig. 5b) was greatest. Although, in some areas otters consumed largely native species, taken as a whole main the fish eaten by otters were, from nature conservation point of view, the problematic non-native species. In summary, the main food of otters living on all six oxbow lakes in the Gemenc Area was fish. On the basis of diet composition, the feeding habits of otters differed between these areas, this may have arise from different environmental conditions. It draws attention to the necessity of differential habitat management of the sensitive valley flat. The results may be useful in the conservation of the Eurasian otter and management of the habitats in flood-plain of the Danube River. Acknowledgements Thanks to Zoltán Sallai for the fish data.
