Regional assessment of soil type and land occupation influence on ecosystem services

As highlighted by recent regulations in Europe and worldwide, the multifunctionality of soils and their capacity to deliver services to societies are of increasing importance to land planners and decision makers. Soils provide multiple ecosystem services (ES) including food production, biomass-energy and contribution to climate change regulation through carbon storage. These services need to be estimated and visualised at relevant scales in order to improve their consideration in land planning decisions.

This project aims to map interdependent bundles of soil ecosystem services at a regional scale so that the effect of land planning decisions on ES delivery can be apprehended by stakeholders. The study site is a 320 km² rural region in Meuse/Haute Marne, France, composed of 56% cropland, 30% forest and 14% grassland. The pedological properties are provided by 85 soil profiles, grouped into 8 dominant soil types, and a 1/50,000 pedological map. Soil typology is dominated by Calcaric cambisols in the agricultural valleys, but features also deep silty and acidic soils in the forested plateaus, shallow rocky calcaric soils on the hillslopes, and deep clay-rich hydromorphic soils in the alluvial valleys.

Using an expert-based decision support model (Destisol¹), soil functions and ecosystem services were scored for all spatial units defined by soil type, slope category and land cover. Functions are calculated based on the soil bio-physico-chemical properties across the whole depth of the pedons. Scores, ranging from 0 to 3, are based on expert-based rules defining threshold values for all soil indicators. Correction factors are applied to the ecosystem service scores to account for the effect of land cover. Finally, correlated bundles of ES across all spatial units are obtained by principal component analysis.

Our results synthetise the effect of soil type on ecosystem services provision, and display the spatial synergies and tradeoffs through three maps of ES bundles. The first ES bundle map compiles the provisioning services (food production, provision of construction wood, provision of biomass energy), which depend dominantly on land use. The second map shows the hydrological regulating services (water quality, erosion mitigation and flooding mitigation), which depend on slope, land use and soil hydromorphy. The third map shows the climate and biological regulating services (contribution to climate change regulation through carbon storage, local cooling effect, biodiversity), which depend on land use, soil depth, rock fragment content and organic matter content. Going forward, maps of ES bundles could be generated for different land planning scenarios to assess the ensuing losses and gains of ES, and promote a more holistic consideration of soil ES by stakeholders.

Reference: 1. Blanchart, A. et al. Towards an operational methodology to optimize ecosystem services provided by urban soils. Landsc. Urban Plan. 176, 1–9 (2018).