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AbstractThe present study contains the results of a study on terrestrial isopod (Crustacea: Isopoda: Oniscidea) samples collected by pitfall traps from five different habitats during four different months in different seasons (late spring, early summer, early autumn, and late autumn) during 2012. All sampling plots were located in Kaunas city. As a result, three species were identified: Trachelipus rathkii(Brandt, 1833), Porcellio scaber(Latreille, 1804), and Oniscus asellus(Linnaeus, 1758). All species found had previously been known from Lithuania. T. rathkii, a eurytopic species, dominated in all studied habitats. Low species richness and diversity might be due to a selective nature of the sampling method. Abundance (surface activity) showed a seasonal pattern. The sample size of the superdominant T. rathkiiallowed calculating a temporal sex ratio for this species: females dominated in all habitats and in almost all periods.

We studied abundance and diversity patterns of terrestrial isopod assemblages along a ‘micro-scale’ vertical gradient in sinkholes in the Aggtelek National Park, Hungary. Time restricted manual sampling yielded ten native species, including endemic and rare ones. Along the gradient we found no major differences in species richness and -composition, and abundance decreased from the bottoms to the upper zones of the sinkholes. Species specific habitat preference on a vertical gradient showed two distinct groups by indicator species analysis: occurrence of habitat “generalists” was irrespective of vertical zones while “specialists” were restricted to the bottoms of the dolines. The latter group is formed mainly by rare species. We found that both diversity and evenness of isopod assemblages were highest in the bottom zone. Our results draw the attention to the significance of such common, yet undiscovered surficial depressions that can provide shelters for rare and specialist species and can provide shelter for survival of populations under changing climatic conditions.