Moving towards integrating soil into spatial planning: No net loss of soil-based ecosystem services.

Degradation of ecosystems and the related loss of ecosystem services have called for new policies to achieve no net loss (NNL) of or even net gain between detrimental environmental impacts and restoration or preservation measures. While biodiversity offsetting has a long tradition, soils have rarely been considered in the accounting. Considering the crucial role of soil for ecosystem functioning and biodiversity and the increasing pressure on soil resources, we investigate how a NNL strategy building on a soil-based ecosystem services index can help steer sustainable spatial development. An ecosystem services' soil quality index allows to explicitly address the interests of a broad range of stakeholder on soil uses. Using a market-driven spatial planning instrument based on a land price fee linked to the soil quality index, we demonstrate how soil quality loss and related ecosystem services could be reduced by up to 60% compared to current practice in a case study in Switzerland. More importantly, the suggested instrument allows to account for the spatial variability of the supply of the ecosystem services and the diversity of stakeholder demands for various soil qualities. We close with a discussion on the consequences of implementing a soil-based NNL strategy for spatial development and its generic application for steering settlement development.