Orthoptera community shifts in response to land-use and climate change – Lessons from a long-term study across different grassland habitats

Abstract

Semi-natural grasslands are among the most species-rich ecosystems worldwide. However, the maintenance of grassland biodiversity is seriously threatened by land-use change. Additionally, climate change is increasingly affecting biotic communities in grasslands. In this study, we examine Orthoptera community shifts in response to land-use and climate change in three different grassland habitats in a Central European low mountain landscape.Orthoptera strongly responded to environmental changes between 1994 and 2015. Both annual and summer temperatures increased during the study period. Apart from climatic changes, the studied habitats were unequally affected by land-use change. Due to the continuity of habitat management, habitat quality has not substantially changed in calcareous and mesic grasslands. However, abandonment has frequently contributed to habitat deterioration in wet grasslands. Orthoptera species richness in the well-managed grassland types increased, while it did not change in wet grasslands. The increase in species richness was mainly caused by an expansion of habitat generalists and mobile species in response to global warming. In comparison, the number of habitat specialists and species with limited dispersal ability did not change in any of the grassland types. Species-turnover rates were higher in mesic and wet grasslands. Accordingly, we detected an increase of the Community Temperature Index (CTI) in these habitats.The results of our study imply that the response of Orthoptera communities to global warming depend on the quality and availability of suitable habitats. Hence, sustaining traditional land use in semi-natural grasslands and the establishment of dense habitat networks is essential to promote Orthoptera diversity.