首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   15篇
  免费   0篇
  2023年   1篇
  2022年   1篇
  2021年   1篇
  2012年   1篇
  2006年   1篇
  2005年   5篇
  2003年   1篇
  2002年   1篇
  2001年   2篇
  1998年   1篇
排序方式: 共有15条查询结果,搜索用时 15 毫秒
11.
12.
13.
The STAR project: context, objectives and approaches   总被引:20,自引:20,他引:0  
STAR is a European Commission Framework V project (EVK1-CT-2001-00089). The project aim is to provide practical advice and solutions with regard to many of the issues associated with the Water Framework Directive. This paper provides a context for the STAR research programme through a review of the requirements of the directive and the Common Implementation Strategy responsible for guiding its implementation. The scientific and strategic objectives of STAR are set out in the form of a series of research questions and the reader is referred to the papers in this volume that address those objectives, which include: (a) Which methods or biological quality elements are best able to indicate certain stressors? (b) Which method can be used on which scale? (c) Which method is suited for early and late warnings? (d) How are different assessment methods affected by errors and uncertainty? (e) How can data from different assessment methods be intercalibrated? (f) How can the cost-effectiveness of field and laboratory protocols be optimised? (g) How can boundaries of the five classes of Ecological Status be best set? (h) What contribution can STAR make to the development of European standards? The methodological approaches adopted to meet these objectives are described. These include the selection of the 22 stream-types and 263 sites sampled in 11 countries, the sampling protocols used to sample and survey phytobenthos, macrophytes, macroinvertebrates, fish and hydromorphology, the quality control and uncertainty analyses that were applied, including training, replicate sampling and audit of performance, the development of bespoke software and the project outputs. This paper provides the detailed background information to be referred to in conjunction with most of the other papers in this volume. These papers are divided into seven sections: (1) typology, (2) organism groups, (3) macrophytes and diatoms, (4) hydromorphology, (5) tools for assessing European streams with macroinvertebrates, (6) intercalibration and comparison and (7) errors and uncertainty. The principal findings of the papers in each section and their relevance to the Water Framework Directive are synthesised in short summary papers at the beginning of each section. Additional outputs, including all sampling and laboratory protocols and project deliverables, together with a range of freely downloadable software are available from the project website at www.eu_star.at.  相似文献   
14.
15.
The spread of non-indigenous species and the decline of autochthonous ones are leading to a homogenization of freshwater fauna in terms of systematic units, but the functional consequences are poorly documented. We studied the peculiar case of the lower, French section of the Moselle River where 20 invertebrate species have been introduced since 1854, with a rate increasing exponentially with time. Dredge sampling performed in 1994, 1996, 2000 and 2001 at four sampling stations allowed for an evaluation of faunal changes in terms of composition, structure and function. During this period, no structural changes were recorded in spite of multiple, new and successful introductions. The evaluation of functional modifications was based on a typology of taxa exhibiting homogeneous biological/ecological traits. Functional diversity, measured as the diversity of taxa distribution among functional groupings, revealed a significant increase between 1994/1996 and 2000/2001 because those species that were over-represented during the former period reached more equilibrated densities during the latter. The major, indirect implications of these functional changes are discussed.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号