Ábrahám Levente (szerk.): Válogatott tanulmányok VI. - Natura Somogyiensis 19. (Kaposvár, 2010)
HORVÁTH GY., HERCZEG R., TAMÁSI K. & SALI N.: Nestedness of small mammal assemblages and role of indicator species in isolated marshland habitats
HORVÁTH ET AL.: SMALL MAMMALS 293 0.55 0.5 0.45 0.4 I 0.35 1 °" 3' 5 0-250.20.15 0.1 0.05 0 Mlcromys minutus ** # Sortx minutus * * Microtia arvaJis * * Apodemus flavicollis * Apodemus sylvaticus * Microtia oeconomus ' Arvicola terrestris" K£ 1 Crocidura suaveolens * Neomys fodiens * Rattus rattus ' My odes glareolus ' ' • KO 1 Fig. 3: Dendrogram of the habitats in 2005 (Bray-Curtis-index, UPGMA). Species possessing significant maximum indicator values are marked (*: P < 0.05, **: P < 0.01) fodiens) and black rat (R . rattus) seemed to be indicator species. While the lesser whitetoothed shrew indicated habitat alteration occurring because of human disturbances (regular mowing) in the area of Keleti-berek between 2001-2004, the two other species indicated the higher water level of the canal-flanked Ingói-berek (Fig. 3). Receiving significant indicator value in case of the bank vole (M glareolus) appeared as an unexpected result through the analysis, because this species can not be considered as a character species regarding marshland habitats. The IndVal values of the bank vole were not expoundable for a group of habitats based on the quantitative data, but for a single habitat - Rózsa-berek (R 1) - where it appeared as a rare species of the small mammal community (Fig. 3). The recorded presence of bank vole in the small mammal assemblage of the examined mosaic-like sedgy habitats was due to the isolated willow groups. Contrary to species characterized by lower character values there were three species that received higher IndVal values than 55 % (M minutus, M. arvalis, A. sylvaticus), however only the highest value for the harvest mouse (M minutus) (68.82 %) can be considered as a symmetrical indicator species among them. Since the harvest mouse was present in the habitat patches of Keleti-berek and the Halász-rét, therefore it appeared as a character species of one habitat group of the Kis-Balaton marshland area. On the fourth level of the habitat hierarchy the two Apodemus species (A. flavicollis, A. sylvaticus) showed up in the disturbed habitats of Keleti-berek, and the bank vole indicated altered habitat quality due to the disturbances (Fig. 3). On the basis of the 2006 trapping data some species occurred in smaller proportion in more habitats. Among others we received smaller abundance values for the water shrews (N. fodiens, N. anomalus) and the lesser white-toothed shrew (C. suaveolens), however in terms of faunistical and nestedness analyses these are valuable information. In this
