Diversity, productivity and resilience in agro-ecosystems: An example from cereal production in Southern Italy

The relationship of crop species diversity to productivity and resilience has been extensively investigated in the scientific literature on agro-ecology. Most of the evidence indicates that there are some beneficial effects of crop species diversity on the functioning of agro-ecosystems1. A prime example is the work of Tilman and colleagues. In a series of plot experiments, they find that plant biomass is an increasing function of the diversity of species (Tilman and Downing 1994; Tilman et al. 1996; Tilman et al. 2005). Thus, higher levels of diversity are associated with greater productivity in the agro-ecosystem (Giller et al. 1997).