Contrasting Patterns of Plants, Bees, Hoverflies and Spiders in Different Habitats in a Central European Agricultural Landscape

Semi-natural grasslands and their biodiversity decline rapidly, although they are key elements of agricultural landscapes. Therefore, there is a need for the re-establishment of semi-natural grasslands in intensively managed farmlands (e.g., via sowing wildflower seeds). Our knowledge, however, is limited on how different arthropod groups may respond to such newly established wildflower fields. This knowledge gap is especially relevant for the Pannonian biogeographical region, and more generally for Central Europe, where there is little to no evidence so far. We aimed to compare three different habitats (i.e., sown wildflower fields (WFF), semi-natural road verges and adjacent crop fields) in terms of their species and individual numbers and assemblage compositions to reveal differences between primary producers (plants), pollinators (bees and hoverflies) and predators (spiders). We selected eight landscapes in Central Hungary within conventionally managed crop areas. We analysed species and individual numbers by generalised linear mixed models (GLMM) and the assemblage composition with non-metric multidimensional scaling for each taxon in the three habitats. Crop, road verge and WFF habitats had distinct assemblages for each studied group, indicating clear separation among habitats. There are, however, contrasting patterns in the diversity measures of the studied groups. Crop fields are the poorest in both species and individual numbers, road verges harboured the highest abundance of spiders, while WFF had the most bees and plants. No clear pattern for hoverflies emerged. Our results suggest that the studied habitats do not harbour all groups in equal share. We propose that the design of future restorations in Central European farmlands should target a diversity of habitat types needed to support a wide range of functional groups.