Đa dạng sinh học, chức năng hệ sinh thái, và Quản lý dịch hại côn trùng trong hệ thống nông nghiệp Ngày nay, các nhà khoa học trên toàn thế giới đang ngày càng bắt đầu nhận ra vai trò và tầm quan trọng của đa dạng sinh học trong các hoạt động của hệ thống nông nghiệp (Swift et al, 1996). | CHAPTER 5 Biodiversity Ecosystem Function and Insect Pest Management in Agricultural Systems Miguel A. Altieri and Clara I. Nicholls CONTENTS Introduction The Nature and Function of Biodiversity in Agroecosystems Patterns of Insect Biodiversity in Agroecosystems Plant Biodiversity and Insect Stability in Agroecosystems Patterns of Landscape Structure and Insect Biodiversity Conclusion References INTRODUCTION Today scientists worldwide are increasingly starting to recognize the role and significance of biodiversity in the functioning of agricultural systems Swift et al. 1996 . Research suggests that whereas in natural ecosystems the internal regulation of function is substantially a product of plant biodiversity through flows of energy and nutrients and through biological synergisms this form of control is progressively lost under agricultural intensification and simplification so that monocultures in order to function must be predominantly subsidized by chemical inputs Swift and Anderson 1993 . Commercial seedbed preparation and mechanized planting replace natural methods of seed dispersal chemical pesticides replace natural controls on 1999 by CRC Press LLC. populations of weeds insects and pathogens and genetic manipulation replaces natural processes of plant evolution and selection. Even decomposition is altered since plant growth is harvested and soil fertility maintained not through nutrient recycling but with fertilizers. One of the most important reasons for maintaining and or encouraging natural biodiversity is that it performs a variety of ecological services Altieri 1991 . In natural ecosystems the vegetative cover of a forest or grassland prevents soil erosion replenishes groundwater and controls flooding by enhancing infiltration and reducing water runoff. In agricultural systems biodiversity performs ecosystem services beyond production of food fiber fuel and income. Examples include recycling of nutrients control of local microclimate regulation of .
