The conversion of conventional production systems, characterized by monocultures with elevated use of inputs, to diversified, low-input systems is based upon two agroecological pillars: habitat diversification and improved management of organic soil content. The functioning optimum of agroecosystems depends on spatial and temporal design choices that foster synergies between above- and below-ground biodiversity, which determine key ecological processes: biotic regulation, nutrient recycling and productivity. The agroecological transition can be monitored by a set of sustainability indicators.