Effects of different mowing regimes on orthopterans of Central-European mesic hay meadows

Method, frequency and date of mowing influence the presence and population size of Orthoptera species, which show strong dependence on the vertical structure of grasslands. Responses of orthopteran assemblages to the effects of various mowing regimes applied to different parts of the same habitat are still not fully understood. In this study, we asked how different mowing regimes (mowing in May; mowing in September; mowing in May and September; abandonment of mowing) influence species richness, Shannon diversity and density of local orthopteran assemblages on a small spatial scale in Central European mesic hay meadows. Furthermore, the study aimed to determine the type of meadow management that is most suitable for preserving local orthopteran assemblages. The date of mowing had no significant overall effect on species richness, density or diversity of grasshoppers. However, grasshopper species richness and Shannon diversity were reduced immediately after mowing (in June sampling of sites mown in May), and rose later in the season. Grasshopper density was low on abandoned sites which were not mowed in the last ten years and there was a negative correlation between orthopteran density and vegetation height. Nymphs, on the other hand, showed elevated density just after mowing which was reduced later in the season. Life forms of the orthopteran assemblages showed dominance of pratinicol species. Silvicol species were found only in abandoned habitats, while arbusticol species were found only on abandoned patches and patches mown in September. Results showed that the long-term preservation of natural orthopteran assemblages in mesic hay meadows would benefit from landuse practices which are diversified spatially and temporally, as practiced in traditional extensive management regimes