Flower borders are now increasingly installed as an agri-environmental measure to improve biodiversity in the agricultural landscape. However, latest studies show that not all flowers are even attractive to wild pollinators, and that an optimised composition and proportion is necessary, especially for the proper development of perennial flower strips in farmland.

In addition, appropriate mowing schemes are also needed for perennial flower strips to better manage succession, especially in regions with high nitrogen depositions, because current schedules do not sufficiently address the diverse needs of insects, including pollinators. Effective mowing management should provide floral diversity with staggered flowering times throughout the flying season, but should also create sufficiently varied habitats with shelter, nesting and mating sites for insects.

To tackle these challenges, perennial flower strips are being installed in this project at various locations (pollinator blocks in the Limburg region and the East Flanders region) based on optimized seed mixes, developped by the Flemish Land Agency (VLM) and Ghent University. An innovative mowing management method will also be tested here, the Three-strip management (Parmentier, 2023). This method involves dividing the flower strip into three strips using curved rather than straight cutting lines. During each mowing cycle, a third is left unmown, as a refugia zone, while clippings are removed to reduce soil nutritional status and reduce succession. The use of overlapping curved lines aims to maximize the variation in patterns, creating a spatio-temporal variation in the (re)growth of flowering plants and tussocks.

In this project, perennial flower strips based on optimized versus standard mixtures will be compared and the effects on pollinators will be monitored (with a focus on wild bee assemblages). In addition, the effects of biodiverse-oriented mowing management will be assessed, comparing Three-strip management with regular management, as currently included in management contracts with farmers.

The conclusion from this study will be taken into account by the VLM as an governmental advisory organisation to enhance the current management agreements, and thus contribute to making the current agricultural landscape more nature-inclusive.