Exploring the value of thematic urban ecosystem accounts in Western Balkan countries to inform urban greening actions

Urban ecological health is increasingly prioritised in Europe, as reflected in the EU Biodiversity Strategy 2030, the Nature Restoration Regulation, and the amended Regulation on Environmental-Economic Accounts. Translating these commitments into effective greening policy and planning actions that halt and reverse urban ecological degradation requires standardised, spatially explicit indicators. This study explores the utility of the System of Environmental-Economic Accounting–Ecosystem Accounting (SEEA-EA) framework for developing thematic urban ecosystem accounts as integrated metrics to inform urban greening in the Western Balkans. We constructed pilot accounts for the Western Balkans for 2018, with particular focus on Horizon-funded CROSS-REIS countries, where local accounts were also developed for representative municipalities (Kranj, Rijeka, Niš, Podgorica, Tirana) for 2018 and 2021. Accounts include ecosystem extent, four condition indicators (imperviousness, green space, tree cover, PM10 concentration), and the ecosystem service air filtration, estimated via PM10 deposition onto vegetation. Results were benchmarked nationally against EU-EFTA countries and the UK and locally against pilot Italian municipalities of the National Biodiversity Future Center. Western Balkan urban ecosystems fall within the European range but display a more homogeneous profile, confirmed by permutation tests and largely explained by shared climate and urban classes. The accounts support quantitative baselines for tracking urban ecological degradation (e.g., tree cover loss), while revealing differences between entire urban ecosystems and their built-up cores. Overall, these accounts can provide a standardised, multi-scale evidence base to inform the setting of policy targets and their adaptation over time, supporting the Western Balkans' environmental management needs on their path towards EU integration.