Cost-effective conservation of multiple goals in grasslands: synergies and trade-offs

Permanent grasslands in Europe are essential for biodiversity and the provision of ecosystem services, but are increasingly threatened by land-use intensification. In the past, grassland conservation has mainly focused on “traditional” conservation goals such as species richness and endangered species, but has rarely considered alternative goals that address trophic interactions, ecosystem services, or ecosystem resilience. Using data from the research platform Biodiversity Exploratories, we adapted an existing optimization procedure to optimize single and joint conservation goals for butterfly and plant communities in grasslands in two regions in Germany. For all grassland sites, we assessed the costs associated with each management measure and the ecological state measured by multiple attributes. For each region, we ran three optimizations: one ecological (budget-unconstrained), and two cost-effectiveness optimizations with a low and a medium budget (budget-constrained). We compared selected grassland management measures, their costs, and ecological effects for different goals between optimizations and between different goals within the same optimization. Cost-effectiveness optimization can achieve high levels of conservation goals with low budgets, reaching up to 80 % of the maximum achievable in the ecological optimizations while requiring only 30 % of the budget. Trade-offs with other goals were inevitable but were minimized by jointly optimizing over multiple goals. Optimization results and trade-offs varied between regions, highlighting the need to design and implement region-specific management measures. Our study shows that promoting multiple conservation goals simultaneously across taxonomic boundaries is an ecologically and economically viable option.