2012. szeptember 19., szerda

Kőrösi et al. (2012) Insect Conservation and Diversity

KŐRÖSI, Á., BATÁRY, P., OROSZ, A., RÉDEI, D. and BÁLDI, A. (2012): Effects of grazing, vegetation structure and landscape complexity on grassland leafhoppers (Hemiptera: Auchenorrhyncha) and true bugs (Hemiptera: Heteroptera) in Hungary. Insect Conservation and Diversity, 5: 57–66. doi: 10.1111/j.1752-4598.2011.00153.x

1. Agricultural intensification is a major cause of biodiversity loss in European farmlands. Grasslands are particularly important habitats for the conservation of rich insect assemblages of Central and Eastern Europe. Although regular grazing or mowing of these grasslands is required to maintain diversity, there is no information about how such management and other factors influence Hemiptera assemblages.
2.  We studied leafhopper and true bug assemblages in semi-natural grasslands in three regions of the Great Hungarian Plain. We investigated how local vegetation factors and landscape complexity influence assemblages and whether they interact with management effects.
3.  Seven pairs of intensively (>1 cow/ha) versus extensively (∼0.5 cow/ha) grazed pastures were sampled in each region by sweep-netting.
4.  Sward height was the most important explanatory factor for leafhoppers (84 species, 27264 individuals), as it increased both species number and abundance, and influenced assemblage composition. The extent of grassland surrounding the sample sites negatively affected leafhoppers, whereas extensive grazing decreased abundance and influenced composition. True bug assemblages (140 species, 6656 individuals) were positively affected only by mean sward height, whereas regional differences determined the community composition of both taxa.
5.  We conclude that vegetation structure is the primary factor shaping Hemiptera communities and that the various types of grasslands studied are all important habitats for the taxon. Therefore, cattle grazing in its current form is beneficial for the rich Hemiptera fauna in lowland pastures of Hungary. However, in some cases, local and landscape factors and great regional differences may confound the effects of grazing, and this must be considered in conservation planning in the future.

Abundance; cattle pastures; community composition; grazing intensity; landscape structure; semi-natural grassland; species richness; sward height

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