Lanszki József - Ábrahám Levente (szerk.): Vadon élő vidrák Magyarországon - Natura Somogyiensis 14. (Kaposvár, 2009)
WILD LIVING OTTERS IN HUNGARY (SUMMARY)
Wild living otters in Hungary The present book features the Eurasian otter (Lutra lutra) as investigated between 1991 and 2008 in Hungary. The main topics and results are the following: Distribution and factors influencing occurrence of otters The aim of the study was to test a new otter survey method recommended by the IUCN/OSG, and supplemented with Hungarian experiences, on the catchments of the Dráva, Kapós, Koppány and lower part of the Danube River. The survey was performed between December 2006 and 2008. Evidence of otter presence was found in 344 out of 390 localities examined. Otters inhabited all the studied stagnant waters but occurred more rarely in smaller streams (76%). Occurrence (provable) of otters declined statistically along narrow water courses (especially <1 m), in shallow water (<30 cm), in less natural habitats, at bridges formed from pipes or bridges without a shoulder (berm), with increasing intensity of waste deposition, water pollution, road traffic, size of settlement, and disturbance. By using similar survey methods a more accurate picture can be drawn concerning the status and population dynamics of otters and the factors affecting their occurrence in Hungary. Results may be utilized in the otter action plan and in the habitat management plans. Relative spraint density and genetic structure of otter along the Drava River in Hungary In this study we used genetic based approaches to estimating population size and structure of the Eurasian otter along the Drava River in Hungary, and compared these results to traditional survey based methods. The relative spraint density of otter was estimated based on the number of fresh (D f ) and total number (D t ) of spraints collected on standard routes over a two-year period. Nine microsatellite loci were screened, generating 17 individual otter genotypes composed of 45 different alleles. The expected heterozygosity ranged from 0.53 to 0.89 and observed heterozygosity from 0.25 to 0.92. The mean density (Dg) estimated over six different sites was 0.17 individuals per km of shoreline. A close correlation was found between the number of genotypes and spraint counts along a standard route (fresh spraints: r P =0.85, P<0.01; total spraints r P =0.76, P<0.05). All genotypes found within the 50 km-long study area were closely related (D m ranged between 0.08 and 0.21). Genetic structure of otters from two fishpond systems in Hungary Little is known about the genetic structure and population size of the elusive and nocturnal Eurasian otter living by fishponds. The aim of this study was to determine these parameters (genetic structure and population size) on two areas (30-ha Al and 83-ha A2) in Hungary using non-invasive sampling methods for molecular testing (collecting fresh spraints on standard routes monthly over a two-year period). Nine microsatellite loci were screened, generating 18 and 15 individual otter genotypes composed of high number of alleles (47 different) with males being the dominant sex. In the area Al all otters were detected only once, and so most of these were presumed to be transient, while on the A2 area most otters were resident forming two families. The estimated otter density was three times higher on area A 1 (possessing higher fish availability) than on area A2.
