Effects of local management and landscape factors on taxonomic and functional diversity of multiple taxa in managed grasslands

Semi-natural grasslands are among the most biodiversity-rich habitats in European agroecosystems, offering a broad spectrum of resources for many species, including plants, insects, and birds, potentially increasing the provision of key ecosystem services. Grassland biodiversity can be strongly influenced by both local- and landscape-level factors. Understanding how different biodiversity facets respond to biotic and abiotic factors across spatial scales remains challenging; yet this knowledge is essential for guiding management actions that support key ecological processes in agroecosystems. Here, we adopted a multi-taxa and multi-scale approach considering five groups: plants, bees, hoverflies, orthopterans, and birds. We assessed the effects of local management (annual mowing frequency, presence of uncut refuges) and landscape features (urban and agricultural cover, landscape heterogeneity) on taxonomic and functional diversity in managed grasslands. We found that multidiversity was positively associated with the presence of uncut refuges and with landscape heterogeneity, while it was negatively associated with urban and monoculture cover at the landscape level. The effect of mowing frequency was weak, potentially due to contrasting effects on different groups. Structural equation models showed that ecological effects varied across scales, groups, and biodiversity indicators: i) local scale management was particularly correlated with indicators of plants and hoverflies; ii) landscape scale factors had a stronger relationship with birds; iii) bees and orthopterans showed relationships at both local and landscape scales. Since different scales of agroecosystems management showed contrasting effects on different groups, we emphasize the importance of planning both local- and landscape-level management to embrace different facets of biodiversity.