A biodiversity-based paradigm for sustainable agriculture is a potential solution for many of the problems associated with intensive, high input agriculture, and for greater resilience to the environmental and socioeconomic risks that may occur in the uncertain future. The challenge is to understand the combined ecological and social functions of agrobiodiversity, determine its contribution to ecosystem goods and services and value for society at large, and evaluate options for the sustainable use and con servation of biodiversity across the agricultural landscape. Agrobiodiversity is most likely to enhance agroecosystem functioning when assemblages of species are added whose presence results in unique or complementary effects on ecosystem functioning, e.g., by planting genotypes with genes for higher yield or pest resistance, mixing specific genotypes of crops, or including functional groups that increase nutrient inputs and cycling. Simply adding more species to most agroccosystems may have little effect on function, given the redundancy in many groups, especially for soil organisms. The adoption of biodiversity-based practices for agriculture, however, is only partially based on the provision of ecosystem goods and services, since individual farmers typically react to the private use value of biodiversity, not the 'external' benefits of conservation that accrue to the wider society. Evaluating the actual value associated with goods and services provided by agrobiodiversity requires better communication between ecologists and economists, and the realization of the consequences of either overrating its value based on 'received wisdom' about potential services, or underrating it by only acknowledging its future option or quasi-option value. Partnerships between researchers, farmers, and other stakeholders to integrate ecological and socioeconomic research help evaluate ecosystem services, the tradeoffs of different management scenarios, and the potential for recognition or rewards for provision of ecosystem services. This paper considers ways that scientists from different disciplines can collaborate to determine the functions and value of agrobiodiversity for agricultural production, but within the context of understanding how biodiversity can be conserved in landscape mosaics that contain mixtures of land use types. (c) 2006 Elsevier B.V. All rights reserved.
