Ground-dwelling invertebrate communities in mountain grasslands in South Tyrol (Italy): Surveying changes in abundances, diversity, and sex ratio

There are few studies of ground-dwelling invertebrates from alpine grasslands, often with only one or a few samplings per growing season. However, to get a comprehensive picture of the faunal community present, sampling over a full season is required. Here we present data on ground-dwelling macro-invertebrate communities from two differently managed mountain grasslands (i. e. an intensively managed hay meadow and an extensively grazed dry pasture). Both sites were monitored continuously over a full growing season (April to early December) using pitfall traps.

We found considerable differences in abundances of the entire ground-dwelling invertebrate communities and in Araneae species diversity between the two grassland types, with the pasture having the lower abundances (i. e. activity densities as individuals per sampling day) but higher spider species diversity. We still found clear effects of management, most likely due to differences in habitat structure and presumably also in prey availability. Sex ratios of spiders did not differ much between the grasslands, however, a negative effect of mowing on the abundances of Araneae and adult Coleoptera was found. Management intensity negatively affected invertebrate abundances and species diversity, but not population dynamics.