Temporal patterns in the activity density and sex ratio of isopods (Oniscidea, Isopoda) along an urbanization gradient in Denmark

Urbanization effects on terrestrial isopod (Isopoda, Oniscidea) populations were studied in forested areas along a rural-to-urban gradient including a native beech forest, suburban and urban forest fragments in Sorø, Denmark. The seasonal activity patterns of the dominating species (Oniscus asellus, Philoscia muscorum and Porcellio scaber) indicated differences among the areas, but these patterns were idiosyncratic. There were more females than males in most areas. The seasonal patterns of males and non-gravid females were similar and often bimodal; gravid females showed markedly different, usually unimodal activity patterns. Temporal changes of sex ratios were – in each species – characterized by an early summer activity peak of males, followed by the activity peak of gravid females. We suggest that these trends might indicate a reproduction-driven surface activity of males. The small response of the three isopod species to urbanization may reflect their wide ecological tolerance as well as the “soft management” of the urban park

Trichoniscus nivatus Verhoeff, 1917: A terrestrial isopod species (Crustacea: Oniscidea) new to the Hungarian fauna

This is the first report of the occurrence of Trichoniscus nivatus Verhoeff, 1917 in Hungary. The species was captured in natural habitats in two localities of Somogy county, south-western Hungary. Description of known distribution, and figures of male genitalia are given

Microhabitat associations of land snails in forested dolinas: implications for coarse filter conservation

We determined microhabitat associations for 39 land snail species based on multimodel inference and generalized linear mixed models using a comprehensive and micro-scale data set from the Aggtelek Karst Area, Hungary. Patterns of microhabitat associations were highly nested among microhabitat types (litter, live trees, dead wood, rock) with high number of specialist species in dead wood and in rock microhabitats. Species composition was highly predictable in these microhabitats as opposed to live tree and litter faunas. Species richness was affected by microhabitat, topographic factors and local moisture conditions. Species richness in dead wood and rock microhabitats remained high irrespective of the topographic effects as opposed to litter and live tree microhabitats, where richness decreased with drier microhabitat conditions due to topography. Our results imply that consideration of topographic factors and microhabitat quality as part of coarse filter conservation measures could be beneficial to local land snail populations in the face of changing climate and disturbance regimes

Urban areas as hot-spots for introduced and shelters for native isopod species

Isopod assemblages were studied in Budapest, capital of Hungary. The analyses of literary and field data revealed a high species richness (28 species), compared to the total species number (57) in Hungary. Habitats characteristics for the city were categorized as native forests, urban forests, gardens of Buda, gardens of Pest, public parks, densely built-up areas and botanical gardens. We hypothesized that isolated and diverse habitat patches in the city matrix of Budapest support the introduction and establishment of exotic species and the survival of native ones. The composition of assemblages varied among sampling sites, but were characteristic for the biotope categories. We concluded that forests, parks and gardens play an important role in the survival of native isopod populations. Species numbers were highest in the gardens of Buda and in the botanical gardens (both 17 species). The overall presence of cosmopolitan and disturbance-tolerant species indicates an ongoing homogenization process. Key-words: soil fauna, woodlice, urban biodiversity, species introduction, taxonomic uniformit