Soil represents one of the most important reservoirs of biodiversity. It reflects ecosystem
metabolism since all the bio-geo-chemical processes of the different ecosystem components
are combined within it; therefore soil quality fluctuations are considered to be a suitable
criterion for evaluating the long-term sustainability of ecosystems. Within the complex
structure of soil, biotic and abiotic components interact closely in controlling the organic
degradation of matter and the nutrient recycling processes. Soil fauna is an important
reservoir of biodiversity and plays an essential role in several soil ecosystem functions;
furthermore, it is often used to provide soil quality indicators. Although biodiversity was
one of the focal points of the Rio conference, in the 1990s virtually no attention was paid to
activities for the conservation of soil communities. However, with the new millennium, the
conservation of soil biodiversity has become an important aim in international
environmental policies, as highlighted in the EU Soil Thematic Strategy (2006), the
Biodiversity Action Plan for Agriculture (EU 2001), the Kiev Resolution on Biodiversity
(EU/ECE 2003) and afterwards in the Message from Malahide (EU 2004), that lay down the
goals of the 2010 Countdown.