Biodiversity of agroecosystems: past, present and uncertain future

摘要

The accelerating loss of biological diversity throughout the world is an issue of growing scientific and political concern. In some regions which have experienced a great intensification of agricultural production in recent years, this loss has beenvery rapid (Aebischer, 1991), and has provoked a scientific debate about the importance of biodiversity for the sustainability of agriculture (Matson et al., 1997). In parts of Europe, major efforts are now under way to prevent further loss of biodiversity, and even to restore diversity in those agricultural areas which have been most impoverished. However, large-scale programmes of this kind are expensive, and it is often doubtful whether the money used for these purposes is well invested. In this chapter, we argue that effective conservation and restoration of biodiversity must be based upon a sound understanding of the ecological status of the biota of agroecosystems. We describe here the origins and development of this biota, and discuss how biological diversity is affected by the introduction of modern intensive farming systems. We pay particular attention to evolutionary processes and the factors affecting the genetic diversity of species in agricultural systems.