Agricultural landscapes across Europe have been extensively modified, leading to biodiversity loss and reduced ecosystem services. As part of global restoration efforts, initiatives like the UN Decade on Ecosystem Restoration and the EU's Biodiversity Strategy aim to promote the restoration of semi-natural habitats, especially grasslands, to sustain biodiversity and ecosystem services.
This is why, in a SHOWCASE co-funded study, conducted in East Central Europe, project partner HUN-REN Centre for Ecological Research, and Hungarian University of Agriculture and Life Science, assessed how different farmland habitats - crop fields, road verges and wildflower fields (WFFs) - support functional groups such as pollinators and predators. Data were collected over one year, with vegetation surveyed during peak flowering time and arthropods sampled twice to account for seasonal variations. While the short duration of the study poses some limitations, the clear differences observed among the habitats provide valuable insights into their ecological roles.
The study found that crop fields had the lowest plant species diversity due to intensive agricultural practices like plowing, crop rotation, and herbicide use. In contrast, WFFs supported the highest plant richness, including both sown and naturally occurring species, benefiting insect communities. Road verges, though less diverse than WFFs, played a key role as semi-natural habitats, providing connectivity and refuge in an otherwise managed landscape. The different plant assemblages influenced the composition of pollinator and predator communities.
Pollinators, including bees and hoverflies, were most abundant in WFFs, likely due to more floral resources. Road verges supported fewer bees but were valuable for hoverflies, benefiting from denser vegetation and predator protection. This suggests that while WFFs are crucial for pollinator conservation, road verges also contribute significantly to pollinator diversity. Pairwise dissimilarity analyses revealed substantial differences in pollinator species between habitats, highlighting the need for diverse habitats in agricultural landscapes.
Spider populations were most abundant in road verges, where dense vegetation provided shelter and hunting grounds, while crop fields and WFFs had lower numbers. Disturbances in crop fields, such as plowing, disrupted spider populations, and WFFs, being newly established, had not yet developed enough vegetation to support them. However, WFFs have the potential to become valuable habitats over time, contributing to pest control in surrounding farmlands.
Overall, the study highlights the importance of maintaining a variety of semi-natural habitats to support key functional groups that provide essential ecosystem services in farmland. While WFFs play a critical role in pollinator conservation, road verges serve as valuable refuges for predatory species like spiders. By filling a knowledge gap for the Pannonian region, which has been under-researched compared to Western Europe, the study also aims to contribute to the successful implementation of the EU's Nature Restoration Law.
Read the full study here.
Image: Results of the bee (a) species number, (b) individual number, (c) assemblage composition in early summer and mid-summer (d, e, f), respectively. The crosses (×) in (a) and (b) show the number of species and individuals in each of the eight landscape plots separated by habitat types (mean ± SD); crosses are jittered to increase visibility. Letters A, B and C above the boxplots in subplots (a) and (b) indicate significant differences according to the Tukey test. In (c), the observed species are noted by the first four letters of their genus name and the first four letters of their species name—a list of species names and their abbreviations can be found in Appendix Dataset; sampling sites are represented by colourful crosses (×); species names and crosses are jittered for better visibility. R2 and p-value of the PERMANOVA and stress value of the NMDS are indicated in the top right corner. Note that only individuals identified at the species level were included in the species number and NMDS indices, while all observed individuals were included in the abundance indices.