tailieunhanh - ECOTOXICOLOGY: A Comprehensive Treatment - Chapter 21

CỘNG ĐỒNG đặc điểm cơ cấu và tổ chức Các tổ chức của một cộng đồng từ kết quả của interspecific cạnh tranh cho các nguồn lực có sẵn, và được thể hiện cả trong sự phong phú tương đối và phân bố không gian của thành phần loài. (Hairston 1959) Mặc dù có những tiến bộ gần đây, cả hai trong việc mua lại dữ liệu và phân tích của mình, tôi nghi ngờ rằng bất kỳ cộng đồng đa loài là cũng đủ hiểu cho chúng tôi để đưa ra dự đoán về phản ứng của mình để các. | 21 Biotic and Abiotic Factors That Regulate Communities CHARACTERIZING COMMUNITY STRUCTURE AND ORGANIZATION The organization of a community results from the outcome of interspecific competition for the available resources and is expressed both in the relative abundance and the spatial distribution of constituent species. Hairston 1959 Despite recent advances both in the acquisition of data and in its analysis I doubt that any multispecies community is sufficiently well understood for us to make confident predictions about its response to particular disturbances especially those caused by man. May 1984 As with most scientific endeavors the field of ecology is concerned with identifying patterns in the natural world and then explaining the underlying processes responsible for these patterns. Community ecologists specifically focus on characterizing variation in the numbers and types of species found at different locations and understanding the role of biotic and abiotic processes responsible for these differences Bellwood and Hughes 2001 . Changes in species diversity across broad environmental gradients or between habitats have occupied the interest of community ecologists for several decades. Variation in the distribution and abundance of species may be a result of broad geographical patterns . Why are there so many species in the tropics compared to temperate regions or small-scale local phenomena . Why is community composition different between headwater streams and mid-order streams . An appreciation of factors that determine natural spatial and temporal variation in community composition is essential for ecotoxicologists. In order to characterize community responses to contaminants and other anthropogenic disturbances we must first understand the influence of natural spatiotemporal variation on species diversity and composition. This natural variation in community structure is of practical importance because it complicates assessments of .