We studied the structure of spider assemblages in fragments of old coniferous forest in the southern Finnish taiga We sampled spiders with pitfall traps in the interiors and in the edges of the old‐forest patches and in the surrounding managed forests We surveyed assemblages of ground‐dwelling spiders and the relation of species to formerly mentioned three forest‐habitat categories We analysed spider assemblages in relation to vegetation structure as well As in forest spiders there are no habitat specialists, no strict old‐forest species were found However, the spider assemblages of old forests were different from those in the surrounding managed forests The difference was attributable to habitat differences, mainly to reduced tree‐canopy cover in managed forests Large hunting‐spider species (Gnaphosidae, Lycosidae) benefitted from clearcutting and other management measures, whereas the catches of small forest‐living species (Linyphiidae) decreased in plantations and open forests The hunters colonized the edges of old‐forest fragments, and were seldom found in the interior of old forest Size of old‐forest fragment did not affect significantly the spider assemblage The results indicate that a buffer zone of mature forest with closed canopy should be left to surround the old‐growth reserves in order to minimize the edge effect in the fragments

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Carabid beetles (Coleoptera, Carabidae) were collected by using pitfall traps in 68 sites on the Åland Islands, SW Finland The sites were divided into four environmental types 1) cultivated fields and grazed pastures. 2) recently abandoned fields, 3) abandoned, overgrown cultivations, and 4) forests A total of 4901 carabids belonging to 77 species were caught Twenty of the most abundant species were classified into four distributional types according to their occurrence among the various environmental types 1) generalists (five species), 2) field species (five species), 3) species of open habitat (seven species), and 4) forest species (three species) Associations with environmental types were strictest among field species and forest species However, most of the species were found in low numbers outside each preferred environmental type The number of species and species diversity was highest in fields and pastures and lowest in forests, which agrees with previously detected patterns on the mainland Finland Pairwise similarity of the carabid assemblages among the environmental types was highest between the two types of abandoned cultivations The spatial distribution of two carabid species, Pterostichus melanarius and P niger, were examined in detail to ascertain whether any interspecific interaction could help explain their different island‐mainland distribution observed in previous studies

Samples of carabids were collected from two study areas in southern Finnish coniferous forest using continuous pitfall trapping throughout the breeding season. These were compared with samples from combinations of early and late season sampling periods (5+5, 10+10 or 14+14 days in each combination). The same species were abundart in both the smaller samples from combinations of periods and in the whole season samples. There was considerable variation in the total catch of carabids among the 10-day samples (5+5 days) which mainly reflected fluctuation in catch of the abundant species in the early season. About 42% of the total number of species was caught in every 10-day sample, 52% in every 20-day sample, and 61% and 77% in every 28-day sample. Most species not caught during the shorter trapping periods were scarce in the whole season sample (<10 individuals). We suggest that samples obtained by trapping periods of 20 days or more were similar enough to the whole season sample to be used in several types of ecoiogical studies.

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