From Fertile Grounds to Sealed Fields: Assessing and Mapping Soil Ecosystem Services in Forlì’s Urban Landscape (NE Italy)

Abstract

Between 2022 and 2023, the urban soils of Forlì (NE Italy) were surveyed, sampled, analyzed, and mapped over an area of ca. 5700 ha, of which 2820 were sealed. The outcomes of the survey allowed the integration of the existing knowledge about soil and land use with the urban plan and provided the basis to produce a 1:10,000 map of urban soils along with their land capability and an updated 1:50,000 soil map of the municipality. Soil data (textural fractions, pH, organic carbon content) were interpolated over the entire case study area, providing the inputs for locally calibrated pedotransfer functions whose outputs were used to assess a set of seven indicators for the potential supply of soil ecosystem services (SESs): soil biodiversity, buffer capacity, carbon storage, agricultural production, biomass production, water regulation, and water storage. Maps of the seven ecosystem services on a hybrid resolution grid of 25 and 100 m were complemented with an overall urban soil quality map based on the combinations of four different SES indicators. Results show that for several services, hotspots occur not only in the peri-urban agricultural areas but also in unsealed soils within the urban fabric, and that different soils provide high-quality services in diverse constellations depending on the soil characteristics, age and extent of disturbance and degree of sealing.