Soil quality indicators: critical tools in ecosystem restoration

Defining clear goals for ecosystem restoration, and developing effective tools to assess and monitor progress, are critical to achieve restoration success. Soil quality indicators can be valuable assets for ecosystem monitoring and assessment. Recent advances in the development of methodologies for soil analyses, including sensing techniques or molecular methods, provide unprecedented opportunities to integrate soil indicators in restoration programs. Despite the substantial potential benefits of using these indicators as tools in ecosystem restoration, the calibration and establishment of global soil parameters remains a challenge due to large variability in soil, climate, and ecosystem types. This review provides an overview of the current knowledge of soil quality indicators in the context of ecosystem restoration. Examples of relevant soil physicochemical and microbiological indicators, and current and novel methodologies for their assessment, are presented. Furthermore the benefits and challenges for the global integration of these indicators in ecosystem restoration programs are discussed.