tailieunhanh - ECOTOXICOLOGY: A Comprehensive Treatment - Chapter 28

Nghiên cứu về sinh thái cộng đồng là chủ yếu liên quan với sự hiểu biết các yếu tố sinh học và phi sinh học ảnh hưởng đến các mô hình phân phối, sự phong phú và đa dạng loài. Phát sinh cơ chế giải thích cho các mẫu quan sát thấy trong thiên nhiên, bao gồm cả sự phân bố đăng nhập bình thường của sự phong phú, khu vực các mối quan hệ loài, và những thay đổi không gian xảy ra trên gradient vĩ độ hoặc elevational, đã chiếm được sự chú ý của cộng đồng sinh. | 28 Conclusions GENERAL The study of community ecology is primarily concerned with understanding how biotic and abiotic factors influence patterns of distribution abundance and species diversity. Deriving mechanistic explanations for patterns observed in nature including the log normal distribution of abundance species-area relationships and the spatial changes that occur across latitudinal or elevational gradients has occupied the attention of community ecologists for several decades. Our treatment of community ecotoxicology has attempted to explain how communities will respond to one major abiotic factor contaminants. Direct effects of contaminants may result in reduction or elimination of local populations and are generally easier to interpret than indirect effects. An autecological understanding of life history characteristics and species-specific sensitivity to contaminants may be sufficient for predicting direct effects on populations. In contrast indirect effects of contaminants are often subtle and difficult to predict without conducting manipulative experiments. Our limited understanding of the indirect effects of contaminants is surprising especially given the prominent role that research on species interactions . competition predation and mutualism has played in basic community ecology. If ecotoxicologists accept the notion that species interactions are important in regulating natural communities then focused research should be directed at understanding the influence of contaminants on these interactions. SOME PARTICULARLY KEY CONCEPTS Improvements IN Experimental Techniques One of the greatest challenges in community ecotoxicology is separating contaminant-induced changes in species diversity and composition from variation owing to natural factors. While observational studies can provide critical support for hypotheses concerning relationships between contaminants and community responses some researchers feel that experiments are the