Long-term abandonment of mountain meadows affects bumblebees, true bugs and grasshoppers: A case study in the Austrian ALPS

Abstract

We investigated how abandonment of mountain meadows influences bumblebees, true bugs and grasshoppers in two years in the Eisenwurzen region (Austria). We surveyed abandoned (20-40 years old) and annually mown unfertilized meadows. Bumblebees were observed in 20 m2 plots, bugs were collected by sweep netting and grasshoppers identified with a soundscape approach. The insect groups were analysed in relation to plant species richness, flower cover, vegetation cover and the surrounding landscape. Bumblebee species richness and richness of long-tongued species were significantly higher in managed meadows. Similarly, we found significantly more phytophagous bug species in managed meadows, whereas grasshoppers showed no difference between meadow types. Bumblebee species richness and abundance, the abundance of phytophagous bugs and total grasshopper species richness were associated with total flower cover. Surrounding forest area negatively affected bugs, while open landscape positively affected bugs, both regarding species richness and abundance, number of phytophagous species and individuals and individuals overwintering as egg. Species assemblages of the three insect groups did not significantly differ between meadow types. Extensive management is important to preserve bumblebee and bug richness. However, abandoned meadows, which are not yet re-grown into forest can still act as suitable habitats for the three insect groups.