Tage der Biodiversität 2027

Wild bees and hoverflies are important pollinators, yet there is growing evidence that both insect groups are declining worldwide. At the same time, substantial knowledge gaps remain regarding their ecology and distribution. In Austria, in particular, standardized data on pollinators are currently lacking. Therefore, we systematically surveyed wild bees and hoverflies across the agricultural landscape of Austria to provide a baseline for the upcoming EU-PoMS.

The quantitative survey of wild bees covered 199 sites, while hoverflies were surveyed at 50 sites. Each site comprised a 625×625 m plot containing ten randomly selected cross-transects (160 m²). Pollinators were recorded between April and August 2023, 2024 or 2025 for two, three or four times depending on altitude. In addition, semi-quantitative surveys were carried out on further habitat patches within each site that were particularly rich in flowers or structural elements.

Overall, we recorded 55 % of the wild bee species and 28 % of the hoverfly species currently known from Austria. Wild bee species richness was highest in eastern Austria, whereas the highest number of hoverfly species was found in western Austria. Moreover, species richness of both wild bees and hoverflies differed among habitat types and we observed distinct preferences for plant families used as resources by the two groups. Furthermore, we assessed the effect of different agricultural systems and landscape composition in the plot. Agri-environmental measures fostering biodiversity were identified. Our results provide standardized data on the distribution of wild bees and hoverflies in the agricultural landscape across Austria and identify key habitats as well as agricultural practices that can facilitate these pollinator groups and help counteract species loss in the future.