Trade-offs between grassland plant biodiversity and yields are heterogenous across Germany

Abstract

Grasslands are key for food security and provide important ecosystem services. Intensive management, such as frequent mowing, increases productivity but decreases other ecosystem services as well as plant biodiversity. We here estimate large scale effects of mowing frequency on plant species richness and provide spatial assessments of yield-species richness trade-offs. We use a unique, multisource remote sensing-based dataset covering all permanent agricultural grassland fields across Germany (N = 1,313,073) over four years to estimate the causal impact of mowing frequency, as a proxy of grassland management intensity, on plant species richness. We identify spatially explicit and heterogeneous treatment effects using generalized random forests. We find that more frequent mowing significantly reduces plant species richness, but these effects vary by environmental and socioeconomic context. We quantify the trade-offs between species richness and yield due to changes in mowing frequency, finding an average cost of 126 euros per additional plant species, and demonstrate how spatial targeting can improve the cost-effectiveness of a hypothetical conservation policy, reducing this cost to 51 euros per species. Motivated by the 30 by 30 goal to protect 30% of terrestrial ecosystems by 2030, we further estimate opportunity cost of marginally extensifying 30% of German grasslands to be 131–181 million euros annually, depending on targeting priorities.