Biodiversity indicators for result-based agri-environmental schemes – Current state and future prospects

Many agricultural policies target the conservation of biodiversity worldwide. Result-based agri-environmental schemes can be more effective and efficient than the more commonly used action-based schemes. The efficiency of result-based schemes, and thus their likely inclusion in agricultural policy frameworks, depends critically on the indicators used to measure biodiversity. We investigate how biodiversity indicators for result-based schemes might be designed and implemented. To this end, we first conduct a systematic review of the scientific literature to identify the range of proposed biodiversity indicators. Second, we synthesize the currently used biodiversity indicators in existing result-based agri-environmental schemes. Third, we compare the proposed and implemented indicators. Fourth, we provide an overview of planned result-based schemes under the 2023–27 reform of the EU Common Agricultural policy. Fifth, we propose how the schemes and indicators might be improved by drawing from technological advances. Our analysis of proposed schemes shows that most schemes use vascular plants as indicators, representing plant species diversity in grassland. These indicators are designed and applied uniformly for large regions such as states or countries. Recently published papers propose more often indicators that consider more biodiversity aspects and are adapted to conditions at smaller scales. We observe similar patterns for currently implemented as for proposed schemes: They are using mostly vascular plants to represent grassland plant species diversity. Moreover, implemented schemes and their indicators are also rather simple in their design and not adapted to smaller regional conditions. More recently implemented schemes are taking both dimensions increasingly into account. Policymakers need to consider their objectives when choosing and designing biodiversity indicators and result-based schemes. They often face trade-offs between improving biodiversity and costs. Therefore, they need to decide which aspects of biodiversity should be considered and how many thresholds that trigger payments should be established. However, studies showed that some indicator designs allow policymakers to cost-effectively consider different aspects of biodiversity. Furthermore, policymakers need to select the indicators based on whether they want to conserve existing or restore lost biodiversity. Finally, new technologies can help improve the design and monitoring of biodive