Environmental protection and human food security co-exist in a critical balance, one that is often difficult to get right. The pressures of population rise, farming intensification, and loss of habitats and species mean that protections afforded under the EU’s Common Agricultural Policy are pivotal to the conservation of agri-ecology. In the EU, agri-environment schemes encourage farmers to undertake environmentally friendly practices and are thus vital to the objective of sustainable agriculture. This Thematic Issue looks at some of the impacts that AES have had on European farm ecosystems, biodiversity and farmers.