“Three-strip management”: introducing a novel mowing method in perennial flower strips and grass margins to increase habitat complexity and attractiveness for pollinators

Abstract

Flower margins are widely adopted as agri-environment measure (AEM) to enhance farmland biodiversity. However, perennial flower margins need appropriate mowing schemes to manage succession, especially in regions with high nitrogen depositions, and current schemes inadequately address the needs of arthropods, including pollinators. Effective management should provide floral diversity with staggered flowering times, creating varied sward structures for diverse habitats that support shelter, nesting, and mating sites. To address these challenges, a novel mowing method, called 'Three-strip management,' is proposed. This method involves dividing the margin into three strips using curved instead of straight mowing lines. During each cycle, one third remains unmown for shelter, while clippings are removed to lower soil nutrient status and reduce succession. The use of overlapping curved mowing lines aims to maximize variety in patterns, fostering spatio-temporal variation in the (re)growth of perennials and swards. Unlike Regular rotational management, multiple uneven parts are kept unmown over winter, increasing the number of subzones in different mown states over successive years. In this study, field trials comparing Three-strip management with Regular rotational management reveal positive effects especially during the second year, including higher bee abundance and diversity. Plant-pollinator networks also demonstrate increased interactions. While the study focuses on bees, the potential of the Three-strip management to support other beneficial insects is discussed. Given declining insect populations in agricultural landscapes, this paper offers insights into enhancing perennial flower margins as AEM to support pollinator populations. The novel Three-strip management presents a promising strategy for balancing management needs with diverse insect requirements, contributing to sustainable biodiversity conservation in agricultural settings.