Soil biodiversity and bioindication: From complex thinking to simple acting

Water and air quality have long received much attention from scientific and legislative institutions, and public awareness for these issues is good, but soils have long been comparatively ignored. Soils contain a very high, but mostly unknown biodiversity, and soil biology remains an understudied topic. Soil organisms are a key factor for soil development and in turn depend on soils as a habitat. Bioindication tools based on a fraction of known soil diversity are certainly imperfect but are implemented in order to achieve soil protection goals at policy level. Bioindication tool selection results from compromises between biological and socioeconomic (e.g. effectiveness, cost) constraints. A further challenge is the multi-functional uses of soils and divergent interest, which hampers progress in regulatory policy. Soils are considered as an economic resource (i.e. surface) and their value therefore strongly relies on the land-use type (agriculture, industry, “unproductive” biotope, etc). But soils are also a natural resource (i.e. volume) which environmental and societal functions depend on its intrinsic properties and biological quality. In this article I review the reasons for the low interest in soils, and particularly their biological component, among politicians and the public, and show the existing gap between soil biodiversity and soil policy. In Switzerland, direct and indirect approaches are used to regulate and monitor soils but these do not include biological parameters.

► Soils are complex living environment and poorly understood in the broad audience. ► Soil biodiversity is poorly known; bioindicators are needed to implement policies. ► Soil protection is correlated with its multi-functionality and socioeconomic values. ► In Switzerland the present-day soil protection monitors only chemical properties. ► Research for accurate bioindicators is an ongoing process.