Land-use change is a major driver for changes in biodiversity. In this study, we investigated how the objectives of two conservation strategies (large-scale conservation of species richness versus conservation of diversity hotspots) can be achieved for grasshopper diversity under different scenarios of environmental change (land-use and climate change).
Based on surveys of 95 grasshopper species from 2001 to 2004 recorded by the Swiss Centre for Faunal Cartography, we modelled the actual richness pattern as a function of different environmental variables. The impact of potential future environmental change on species richness was evaluated by applying four land-use scenarios ('liberalization', 'business as usual', 'lowered agricultural production', and 'complete conversion of intensive open land') and one climate change scenario. The effects of the scenarios were assessed at the national scale, as well as on small-scale hotspots.
Environmental change has considerable effect on grasshopper species richness. At the national scale, the number of grasshopper species decreased under the 'liberalization' scenario (-0.24 species per 1 ha pixel) and increased under a climate change scenario (+0.63 species per 1 ha pixel). For most environmental change scenarios, species richness in small-scale hotspots was more negatively affected than on average on the national scale. The response of species richness to the scenarios did not differ significantly between hotspots of endangered and the hotspots of common grasshopper species.
We conclude that conservation efforts at the national scale and small-scale hotspot conservation programs should be combined to conserve species richness most successfully. For the long-term conservation of species richness, common species as well as the combined effects of land-use and climate change have to be considered.