The Tisza River Basin is an important area as it is a green corridor in which there are highly endangered habitats and a high level of biodiversity. The patterns in the species richness of invertebrates and the environmental conditions affecting these patterns are poorly studied in the grassy habitats in the lower reaches of the Tisza River Basin. The present study focuses on the effects of flooding, habitat and landscape features on the species richness of orthopterans at 24 grassland sites in two different landscapes. The relations between the explanatory variables and the pattern of diversity of orthopterans with different life-history traits were studied, using ordination and Generalized Linear Mixed Models. Although the influential factors for the different trait groups differed, we suggest that landscape features are the most important in shaping orthopteran assemblages, whereas habitat characteristics and flooding have comparatively little effect. Habitat characteristics affected only the non-xerophilous and Ensifera species and only the species richness of non-xerophilous orthopterans in flooded and non-flooded sites differed. We emphasize that even in countries where there are still considerable areas of high value natural grasslands, such as Hungary, non-protected meadows, linear grassy habitats (dikes, ditch banks, road verges, etc.) need more attention and should be given higher priority in the conservation of invertebrates., Attila Torma, Miklós Bozsó., and Obsahuje bibliografii
Despite the importance of saprophagous macroarthropods as key facilitators of plant litter decomposition within ecosystems and their likely sensitivity to global climate change and land-use change, a lack of ecological data has precluded attempts to explain their distribution patterns in terms of traits. Using an extensive set of large-scale and long-term biological records, the distribution patterns of 33 woodlice (Crustacea: Oniscidea) species in Britain were characterised by their range size (area of occupancy) and aggregation (degree to which occupied squares are clustered across the range). Body size and seven ecological traits were examined as correlates of range size and fill, while controlling for phylogeny and recording intensity, and comparing fine and broad-scale measures of habitat heterogeneity. Species that used a greater diversity of habitats had larger range sizes. Broad categorisation of habitats (by dominant vegetation) alongside other traits was less accurate in predicting range size than fine-scale habitat (microsites where individuals were discovered) data. The latter explained 25% more variance than broad-scale habitat data, highlighting the value of coupling biological recording of species with data on micro-habitat. Habitat use is an important trait in explaining distribution patterns and we conclude that ensuring land cover heterogeneity will favour conservation of saprophagous macro-arthropod diversity., Bethan V. Purse ... [et al.]., and Obsahuje seznam lileratury
In this study we analysed whether the diet composition of a wintering population (40–70 individuals) of long-eared owls (Asio otus) in northern Italy showed within-season variation, and whether it was influenced by ambient temperature and rainfall. Diet composition was determined by pellet content, and over 5500 prey items were analysed; pellets were collected at 2-wk intervals over two consecutive winters (October to April), 1996–1998. Three out of five main prey categories showed a marked within-season variability in relative frequency in diet, both considering the number of prey items and prey biomass, whereas between-year variability was shown only by a single prey category (Savi’s pine vole). Although rainfall had no influence on diet composition, temperature affected negatively the prevalence of harvest mouse, a relatively unimportant prey category. Thus, the considered weather variables seem to have little influence on the winter diet composition (at the level of individual prey categories) of these owls. However, diet breadth (estimated by the Levins’ index of niche breadth) increased with increasing rainfall and decreasing temperature, when calculated on the proportion of prey items: hence it seems that the owls become more generalists under unfavourable weather conditions.