Legume crops and biodiversity

Modern intensive cropping systems rely on simple cropping sequences, mineral fertilizers and chemical crop protection. This has led to a reduction of crop diversity, simplified land-scapes and declines in biodiversity. However, even today in intensive farming systems, legume-supported cropping has the potential to deliver many ecosystem services, both directly due to unique trait combinations and indirectly via promoting biodiversity and by facilitating services such as pollination, pest control and soil improvement. This chapter outlines the effects of legume cropping on biodiversity, focusing on legume-specific traits and their interactions with agricultural management. Legumes have complex direct and indirect interactions with the surrounding agroecosystem and its management, so it is not possible to fully separate general crop management effects from effects of management that is specific to legume crops, and legume-trait effects. Legumes can benefit farmland biodiversity when included in highly productive cropping systems. Legume crops qualify for the ecological focus areas in ‘greening’ of the Common Agricultural Policy (CAP) of the European Union (EU). Several of the effects of legumes are related to changes in management practices, such as a reduced use of pesticides, fertilizer or soil tillage. Of course benefits for biodiversity may be also partially achieved by other crops and diversified crop rotations. However, legume traits and management practices vary at a species or even cultivar level and so here we provide a general overview of the effects on biodiversity.