Best management practices for multiple ecosystem services: subject-wide evidence synthesis and multi-criteria decision analysis

Abstract

When a farm is managed for one ecosystem service, such as soil conservation, what happens to other ecosystem services? For example, if cover crops are used to reduce erosion or increase fertility, what happens to below-ground biodiversity or water quality? If management practices cause trade-offs between multiple ecosystem services, which practices cause the fewest trade-offs? Based on the methods developed by the Conservation Evidence project (www.conservationevidence.com), we show how subject-wide evidence synthesis, expert assessment, and multi-criteria decision analysis can be used to make transparent and evidence-based decisions about which management practices are the best for multiple ecosystem services. We reviewed the evidence for the effects of twenty farmland management practices (e.g., cover cropping or riparian restoration) on seven ecosystem services (crop production, soil and water regulation, climate regulation, pollination, pest regulation, and biodiversity conservation) in agroecosystems with Mediterranean climates. For each publication that we reviewed, we summarised the effects of each practice on each ecosystem service for which there was quantitative evidence. A group of conservationists and agronomists assessed the evidence that we summarised (scoring each practice for benefits and harms to each service, and scoring the certainty of the evidence), and assigned each practice to an effectiveness category for each service (e.g., “likely to be beneficial” or “trade-offs between benefits and harms”). Based on the scores from this expert assessment, we used multi-criteria decision analysis to make a structured decision about which practices were the best for which combinations of ecosystem services and cost. We also developed an online decision-support tool that allows users to make their own decisions, based on the evidence, by stating their relative preferences for cost, crop production, and other ecosystem services.