Multi-function agricultural biodiversity: pest management and other benefits

This paper reviews two aspects of agricultural biodiversity. 1. The ways in which agricultural biodiversity may be increased to favour pest management are examined. At the simplest level, the structure within a monoculture may be altered by changing management practices to benefit natural enemies. At the other extreme, annual and perennial non-crop vegetation may be integrated with cropping, and biodiversity increased at the landscape level. 2. The existence of a hierarchy for the types of benefits of increased biodiversity is discussed. Vegetational diversity can lead to suppression of pests via 'top-down' enhancement of natural enemy populations and by resource concentration and other 'bottom-up' effects acting directly on pests. Whilst such low-input pest management mechanisms are attractive in their own right, other (non-pest management related) benefits may simultaneously apply. These range from short-term benefits in crop yield or quality, longer term benefits for sustainability of the farming system and, ultimately, broad societal benefits including aesthetics, recreation and the conservation of flora and fauna. Examples are given of such multi-function agricultural biodiversity.