Vascular plant and Orthoptera diversity in relation to grassland management and landscape composition in the European Alps.
Abstract
Several recent studies have considered the relative effects of local vs. landscape factors on diversity of several animal taxa in grasslands. However, very few have considered vascular plant or Orthoptera species, both of which are important biotic components of grassland ecosystems. The general aim of this study was to determine the effect of grassland management and landscape composition, and their potential interactions, on diversity patterns of vascular plants and Orthoptera in Alpine hay meadows. We considered three groups of management regimes defined by different amounts of fertilizer nitrogen applied and cutting frequency: (i) extensive, (ii) low intensive and (iii) intensive meadows situated in different landscape contexts. To evaluate the relative importance of meadow management and landscape composition on diversity patterns, we applied analysis of covariance and variation partitioning analyses. Diversity patterns of both taxonomic groups were affected primarily by grassland management. The extensive management regime was most suitable for conserving high species richness of both taxonomic groups. The intensive meadows were characterized by plant communities dominated by a few ruderal and competitor species, and by Orthoptera communities composed of only a few abundant Caelifera species (e.g. Chorthippus parallelus), while Ensifera species had very low individual densities. Regarding the landscape determinants, plant diversity patterns were not significantly related to any landscape composition variables. In contrast, a high proportion of urban elements and grassland in the surrounding landscape (radius 500 m) affected Orthoptera species richness negatively. Synthesis and applications. The implementation of well-targeted agri-environment schemes for compensation payments against intensification and abandonment of extensive hay meadows seems to be a promising tool to protect both taxonomic groups. In this context, we suggest that the existing Swiss ecological compensation area (ECA) hay meadow agri-environment scheme, which requires at least one cut every year and no fertilizer application, might also be suitable for the Italian Alps. Moreover, the significant influence of landscape composition on Orthoptera diversity suggests that the effectiveness of measures applied at a field scale may be improved by integration of protected area schemes, promoting extensive management at a farm scale.