Biodiversity conservation and productivity in intensive agricultural systems

Agricultural practice in industrialised countries is focused on creating the optimum environment for a single target species (the ‘crop’), by adjusting the environment so that growing conditions for the target species are optimised while those for competing species (e.g. ‘weeds’ and ‘pests’) are deliberately reduced. This approach to the agro-ecosystem has dominated modern agricultural practice, and implies the simplification of ecosystems (Jackson et al. 2005; forthcoming; Pascual and Perrings forthcoming; Perrings et al. 2006). The result is that modern intensive agriculture has largely ignored symbiotic interactions and resource use complementarities between species.