Regionalised Seed Mixture Enables Successful Flower Field Establishment Across Varying Management and Landscape Conditions

Perennial flower fields implemented through agri-environment-climate measures (AECM) are widely used to counteract biodiversity loss. However, little is known about how management factors, such as previous land use and sowing period, as well as landscape context, determine successful establishment of flower fields with few or no agronomically problematic weeds, which can reduce farmers’ acceptance. We recorded the vegetation establishment of 29 flower fields sown with a mixture of native seeds containing 33 species, regionalised for southern Lower Saxony, Germany, over two years. The flower fields, located along a landscape diversity gradient, were sown in autumn or spring and differed in their previous land use (annual crops or AECM fields). From the first to the second year, sown species cover increased by 42.9%, cover of spontaneous species from the seed bank and surroundings decreased by 29.0%. Problematic weed cover was generally low and decreased by 5.0%. Flower fields with previous annual crops had 3.2% less problematic weed cover and 31.4% less spontaneous species cover than flower fields on previous AECM. Sown species cover was higher in previous crop fields in the second year. Only in the first year, autumn sowing increased sown species cover, and spring sowing led to higher problematic weed cover. Sown species established better in low-diversity landscapes, while spontaneous species established better in high-diversity landscapes. Overall, the seed mixture established very well and outcompeted problematic weeds. Flower fields in diverse landscapes also harboured diverse spontaneous species, contributing to the regional species pool. Differences due to management disappeared by the second year. Native seed mixtures with fast growing annual species for weed suppression and regionally adaptable perennial species that establish across a wide range of environmental conditions are highly suitable to create habitats that enhance biodiversity and deliver multiple ecosystem services in agricultural landscapes.