Beyond surface change: assessing ecosytem services capacity loss from land-take in Wallonia

Understanding the ecological consequences of land-take requires moving beyond land-use and land-cover (LULC) data alone and considering ecosystem condition. This study quantifies land-take in Wallonia (Belgium) between 2007 and 2018 and characterises the affected areas using key abiotic soil and topographic properties, including soil wetness, texture, depth, hydromorphy, slope and aspect, in order to identify ecologically constrained soils affected by this process. We then assess how these land conversions influence the capacity of ecosystems to deliver services, applying an ecosystem service (ES) capacity matrix. The matrix combines LULC information with mapped soil and topographic properties to integrate ecosystem condition into the estimation of ES changes attributable to land-take. Our findings show an average annual land-take of 21.43 km² (5.87 ha per day), consistent with national statistics, but significantly higher than European estimates, mainly due to methodological differences between land-cover-based satellite imagery and cadastral land-use data. Conversions predominantly affect agricultural land, reflecting long-standing policy concerns about the protection of arable land. However, our study also highlights that ecologically constrained soils, often overlooked due to their limited agronomic value, are nonetheless significantly affected by land-take. These areas, including hydromorphic soil types, occupy relatively small surfaces, yet exhibit a high capacity to support regulating ES. Results indicate a significant decline in the capacity of ecosystems to supply regulating ES, especially water quality regulation and flood risk mitigation. These findings underscore the importance of integrating ecosystem condition data into ES assessments and land-use planning policies, not only to support the goal of preventing further soil degradation (e.g. under No Net Land-Take objectives), but also to move beyond a purely surface-based interpretation of land-take that overlooks the characteristics of the ecosystems affected.