Monitoring soil restoration in an open-pit mine in northern Italy

• Extraction activities significantly affect soil ecosystems.
• A number of years are required to restore soils that in general have become sterile.
• Microarthropod communities are a useful bioindicator of post-mining restoration.

Mining causes significant damage to the environment: the removal of top layers of soil causes loss of structure and functionality, with a subsequent reduction in biodiversity. Soil communities are important for soil formation, they contribute to the improvement of several characteristics of soils and they play key roles in many processes that enhance the success of restoration. Unfortunately, soil fauna are poorly monitored even though they represent a good tool for assessing soil quality. The “La Speranza” quarry in northern Italy was studied from the start of the restoration process in 2008 until 2012. Six sites were selected and monitored annually. Microarthropods were extracted from three replicates of soil drawn from each site, identified to order level and then counted. Both the abundances of taxa and the soil biological indices applied (Shannon diversity index (H’), Pielou's evenness index (J), the Acari to Collembola ratio (A/C) and the QBS-ar index) revealed a good level of soil recovery over the years studied. Furthermore, the edaphic organisms that are generally associated with stable conditions in the soil (e.g. Symphyla, Protura, Chilopoda), appeared in the most recent of the years.