Towards Integrated Ecosystem Assessments: A literature review on linking ecosystem condition indicators to ecosystem services

Ecosystem services (ES) fundamentally depend on ecosystem condition (EC), yet many ES assessments still rely on land-cover proxies, risking biased assessment results as well as weak uptake, meaning limited application of results in decision-making contexts. This review provides a comprehensive overview of how EC indicators are used in ES assessments published between 2018 and 2022. In total, 128 publications have been included in the review, from which 929 EC indicators with a direct or implicit link to one or more ES and 707 ES indicators have been documented. The recorded EC indicators were reclassified according to the Ecosystem Condition Typology (ECT) provided by the System of Environmental-Economic Accounting-Ecosystem Accounting (SEEA EA) and supplementary classes (ECT+). Our analysis identified a focus on terrestrial ecosystems, with under-representation of marine and less intensively managed ecosystems. Within the reclassified ECT and ECT+ indicators, chemical state EC indicators were prevalent, while landscape state and functional state metrics remained under-operationalised. Besides, the share of spatially explicit indicators was limited. Moreover, we found that a significant share of indicators, labelled as EC, were not EC indicators in the strict sense, but instead related to ecosystem extent, ES or stable environmental characteristics, leading to a conceptual blurring between condition, pressure, extent and service indicators. Analysing the link between EC and ES revealed that EC indicators were: (1) primarily quantitatively compared to ES or integrated into ES assessments and (2) most frequently linked to regulating ES. The reviewed literature showed a predominance of positive EC-ES relationships, confirming that ecosystems in better condition tend to support a higher supply of ES. In summary, our review identified progress towards integrated ES assessments, highlighted persistent gaps and stressed the importance of continued efforts to achieve the widespread implementation of EC-enabled ES assessments.