tailieunhanh - ECOTOXICOLOGY: A Comprehensive Treatment - Chapter 20

Như mô tả trong phần trước, sự hiểu biết tác động trực tiếp của những căng thẳng hóa chất trên dân số là một mối quan tâm cơ bản của ecotoxicologists và nhà quản lý. Tuy nhiên, sự tương tác giữa các loài thường vượt qua mức độ phản ứng dân số và có thể đóng một vai trò quan trọng trong cơ cấu cộng đồng trong tự nhiên. Chiếm một mức trung gian phức tạp trong hệ thống phân cấp của tổ chức sinh học, các cộng đồng khác biệt, nhưng có mối liên hệ thân mật, dân số. | Part IV Community Ecotoxicology Chemicals are pre-tested against a few individuals but not against living communities. Rachel Carson 1962 As described in the previous section understanding direct effects of chemical stressors on populations is a fundamental concern of ecotoxicologists and regulators. However interactions among species often transcend population-level responses and may play a significant role in structuring communities in nature. Occupying an intermediate level of complexity in the hierarchy of biological organization communities are distinct from but have intimate linkages to populations and ecosystems. Contemporary questions in basic community ecology address the strength ubiquity and transience of species interactions Strong et al. 1984 as well as the environmental factors that regulate species diversity. Understanding effects of contaminants on species interactions is considered a primary justification for testing effects at higher levels of biological organization Cairns 1983 . Furthermore most monitoring programs developed to measure effects of contaminants on aquatic ecosystems rely heavily on community-level assessments. Because of its rich history of investigating indirect effects the theoretical models and empirical studies in basic community ecology can be used as a framework for predicting contaminant effects Rohr et al. 2006 . In addition to improving our understanding of life history characteristics and other autecological features that determine susceptibility of organisms to chemicals we believe that ecotoxicologists should also consider species interactions and how contaminants affect these interactions. The goal of this section is to apply basic principles developed in community ecology to improve our understanding of how groups of interacting species respond to contaminants and other anthropogenic stressors. REFERENCES Cairns J. Jr. Are single species toxicity tests alone adequate for estimating environmental hazard Hydrobiologia