Management effects on carabid beetles and spiders in Central Hungarian grasslands and cereal fields

Abstract

Modern agriculture is one of the main anthropogenic threats to biodiversity. To explore the effects of agricultural intensification we investigated carabids and spiders in two studies; in 2003 in grasslands and two years later in cereal fields in the same region. Both aimed to study the effect of management on arthropod diversity and composition at local and landscape scales. In 2003, we used a paired design for grasslands (extensively vs. intensively grazed). In 2005, a gradient design was applied with a total of seven land-use intensity categories. In both studies, sampling was carried out using funnel traps with the same sampling effort. Linear mixed models showed that high grazing intensity in grasslands had a positive effect on carabid species richness and abundance, but no effect on spiders. Landscape diversity had a positive effect only on carabid abundance. In the case of cereal fields, the management intensity (nitrogen fertiliser kg/ha) had a negative effect on spider richness and no effect on carabids. After variance partitioning, both local and landscape characteristics seem to be important for both cereal and grassland arthropod communities. Based on our results, we think that current and future agri-environmental schemes should be concentrated on cropland extensification. Low intensity croplands could act as a buffer zone around the semi-natural grasslands, at least in this biogeographic region.