tailieunhanh - ECOTOXICOLOGY: A Comprehensive Treatment - Chapter 30

Các quan điểm được cung cấp bởi O'Neill và Waide (1981) trong các báo ở trên minh họa một trong những thách thức quan trọng hơn phải đối mặt với ecotoxicologists khi cố gắng để hiểu về tác động tiềm năng của con người gây ra những căng thẳng về quy trình hệ sinh thái. Quan điểm này có thể cũng một phần giải thích infrequency tương đối với các quá trình hệ sinh thái được đo trong việc đánh giá sinh học. Bởi vì hệ sinh thái "bất ngờ" (sensu Paine và cộng sự năm 1998.) Có thể là. | 30 Overview of Ecosystem Processes A major stumbling block in the study of ecosystems is their bewildering complexity. O Neill and Waide 1981 INTRODUCTION The perspective offered by O Neill and Waide 1981 in the above quote illustrates one of the more significant challenges faced by ecotoxicologists when attempting to understand the potential impacts of anthropogenic stressors on ecosystem processes. This perspective may also partially explain the relative infrequency with which ecosystem processes are measured in biological assessments. Because ecosystem surprises sensu Paine et al. 1998 may result from focusing on isolated components one potential solution to this bewildering complexity is to develop a comprehensive understanding of emergent ecosystem properties O Neill and Waide 1981 . For example we can readily quantify the contributions of decomposers to nutrient cycling or the influence of predators on energy flow however it is unlikely that we can predict ecosystem consequences based exclusively on abundance or biomass estimates of these functional groups. As described in the previous chapters the idea that behavior of a complex system often cannot be understood solely by analysis of its components is a major thesis of hierarchy theory. The order that emerges from complex systems and the constraints placed on the range of potential interactions in these systems are fundamental differences between randomly assembled populations and a stable ecosystem. The functional redundancy of ecosystems that results from species replacement is a good example of our inability to predict ecosystem responses based on understanding of components. In one of the earlier theoretical treatments of ecosystem ecotoxicology O Neill and Waide 1981 provide several recommendations for research programs in this emerging field 1. Focus on functionally intact systems that reflect ecosystem-level properties. 2. Focus on integrative properties that reflect interactions among physical .