U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska
Date of this Version
2008
Abstract
In the USA, Europe and increasingly in other regions, cropping systems designed for high production output are significant features of the landscape. Deployment of mechanized and high-input cropping systems over the last 50 years has resulted in substantial transformation and fragmentation of major grassland, shrubland and woodland systems throughout the world. These cropping systems are typically less diverse in species composition, structure and ecological functioning than those found in the original plant community (Altieri, 2004). Decreases in plant diversity of agroecosystems (i.e. the crops themselves and surrounding remnants of the original plant system) have negatively affected ecosystem functions (Freemark, 2005). For agriculture, declines in agroecosystem diversity can result in increased crop herbivory and decreased beneficial organisms that feed on pests (Letourneau, 1998; Altieri, 2004).
Agricultural plant diversification is advocated as a remediation method to reverse these pest management challenges associated with modern cropping systems (Banks, 2000; Benton et al., 2003; Altieri, 2004; Schmidt et al., 2004), adding to other efforts to restore disturbed areas to their original plant community (Freemark, 2005). Mechanistically, this approach is based in part on outcomes of vegetation-driven plant-herbivore-natural enemy interactions predicted from the resource concentration, enemies, associational resistance and plant apparency hypotheses (Root, 1973; Banks, 2000; Altieri, 2004).
Comments
Published in Areawide Pest Management: Theory and Implementation (eds O. Koul, G. Cuperus and N. Elliott) p. 81-96