Quantifying Soil Natural Capital and Trade-Offs in Ecosystem Services from Soiltrec and GB Countryside Survey.

Natural capital and ecosystem service concepts are embodied in the ecosystems approach to sustainable development. We discuss the broad concepts of this approach and their relevance and usefulness in soil science. For soil monitoring and large-scale research programmes these concepts can be a particularly good means to convey the implications of soil change at a policy level. However, while soils are given the vital role of a supporting service in the Millennium Ecosystem Assessment, many of the other soil goods and services remain obscured. Furthermore, we argue that focusing on final goods and services will be counterproductive in the long run and emphasize that final goods and services are derived from an ecosystem supply chain that relies on ecological infrastructure. We discuss developing frameworks in the context of soil change and propose that an appropriate ecosystems approach for soils should fully incorporate soil stocks (natural capital), and, show their contribution to stock-flows and emergent fund-services as part of the ecological supply chain. An operational ecosystem concept for soils can, by doing so, draw on much more available data on soil stocks. Such progress toward routine quantification of the soil resource will be facilitated by the identification of appropriate indicators. A synthesis of national-scale data (for England &Wales) highlights knowledge gaps and indicates how monitoring might be developed to respond to the demands of the ecosystems approach, in terms of both measures and scale. Using a spatially extensive database of co-located biophysical measurements (collected through the GB Countryside Survey), we show that in temperate, human-dominated landscapes, ecosystem services are highly constrained by a fundamental productivity gradient; there are immediate trade-offs between productivity and soil carbon storage but potential synergies with other services. These techniques to analyse multiple service interactions could be used inform the development of Spatial Decision Support tools and landscape-scale ecosystem service management options. Understanding and quantifying constraints to multiple ecosystem service delivery in soils is vital for developing management strategies for current and future human well-being.