Mixed effects of sward biodiversity and management regime on ecosystem services

Species-rich grasslands provide ecosystem services such as flora and fauna diversity, forage for livestock, carbon sequestration and water regulation. These ecosystem services can be affected by sward botanical composition and management intensity. However, the effects and interactions of these factors to optimise ecosystem services are not fully known. To address this, we established experimental plots with three types of sward with varying levels of diversity: productive monoculture (PM; perennial ryegrass (Lolium perenne)), biodiverse (BD) and productive biodiverse (PBD), which were subjected to four management regimes ranging from extensive (i.e., low input, late mowing) to intensive (i.e., high input, early mowing). After three years, we found successful establishment of biodiverse swards with high forb cover, particularly under extensive management. Forage dry matter yield was the highest in BD and intensively managed swards. Forage N concentration was the highest in PBD swards and digestible organic matter was the highest in PM and PBD swards. Treatment effects on carbon sequestration and water regulation were minimal. Collectively, diverse swards, different management regimes and their interactions benefit some, but not all, ecosystem services, and highlight the need for careful consideration of sward species composition and long-term management of biodiverse grasslands to achieve site-specific goals.