Global Ecology and Conservation (Nov 2023)
Intensity of grassland management and landscape heterogeneity determine species richness of insects in fragmented hay meadows
Abstract
Traditionally managed grasslands rank among the most species-rich ecosystems. However, in agricultural landscapes of Western and Central Europe, their extent has severely decreased. The remaining patches are mostly fragmented and suffer from habitat deterioration. Here, we studied the effects of environmental conditions on species richness of butterflies and grasshoppers in highly fragmented hay meadows. Our study revealed that environmental parameters at the habitat and landscape level influenced species richness of butterflies and grasshoppers in low-intensity hay meadows. In the univariable models, two groups of parameters consistently affected the number of all and threatened species: at the habitat level, species richness was fostered by structural richness, which was indicative of the overall management intensity of the grassland patches. At the landscape level, a higher number of mowing events in the landscape surrounding the hay meadows had a negative effect and higher elevations exhibiting a cooler and wetter climate had a positive effect on species richness. The former reflected the overall intensity of grassland management in the landscape and the later, together with further predictors (cover of forest, habitat connectivity, slope), the landscape heterogeneity. Consequently, the intensity of grassland management at the habitat and landscape level as well as the landscape heterogeneity, which was also related to land-use intensity, determined species richness of butterflies and grasshoppers. Based on these findings, there is an urgent need to enlarge the proportion of grasslands with low land-use intensity in the wider countryside. Additionally, conservation measures should aim at increasing landscape heterogeneity and habitat connectivity.
