Orthopteran Diversity in Steep Slope Vineyards: The Role of Vineyard Type and Vegetation Management

SIMPLE SUMMARY: Our study evaluated the effects of vineyard abandonment and shrub encroachment and the value of active vineyard management for Orthoptera diversity. We investigated orthopterans in two different vineyard management types (vertically oriented and terraced vineyards) and in vineyard fallows in the Upper Middle Rhine Valley (UMRV) in Germany and determined the effects of local vegetation structures within vineyards and in the surrounding landscape. On the landscape and local scale, woody structures and vineyard abandonment reduced habitat quality, especially for open-adapted Orthoptera species. Management in vineyard inter-rows provided bare ground and supported heat- and open-adapted species while taller vegetation stands on terrace embankments enhanced Orthoptera species richness. We conclude that maintaining viticulture on steep slopes is significant for the preservation of open and herbaceous habitat structures and the conservation of associated Orthoptera species. ABSTRACT: The abandonment of traditional agricultural practices and subsequent succession are major threats to many open-adapted species and species-rich ecosystems. Viticulture on steep slopes has recently suffered from strong declines due to insufficient profitability, thus increasing the area of fallow land considerably. Changing cultivation systems from vertically oriented to modern vineyard terraces offers an opportunity to maintain management economically viable and thus reduces further abandonment. Hillside parallel terraces favor mechanization, and their embankments offer large undisturbed areas that could provide valuable habitats. We investigated the effects of vineyard abandonment, different vineyard management types (vertically oriented vs. terraced), and local parameters on Orthoptera diversity in 45 study sites along the Upper Middle Rhine Valley in Germany. Our results show that woody structures and vineyard abandonment reduced Orthoptera diversity at the local and landscape scale due to decreased habitat quality, especially for open-adapted species. In contrast, open inter-rows of actively managed vineyard types supported heat-adapted Caelifera species. On terrace embankments, extensive management and taller vegetation benefited Ensifera species, while short and mulched vegetation in vertically oriented vineyards favored the dominance of one single Caelifera species. Our results highlight the significance of maintaining viticultural management on steep slopes for the preservation of both open-adapted Orthoptera species and the cultural landscape.