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601.
RIVPACS models for predicting the expected macroinvertebrate fauna and assessing the ecological quality of rivers 总被引:4,自引:0,他引:4
The European Union Water Framework Directive recognises the need for and value of biological monitoring. This paper reviews the modelling approach known as River Invertebrate Prediction and Classification System (RIVPACS
for assessing the ecological quality of river sites using macroinvertebrate sampling. The RIVPACS philosophy is to develop statistical relationships between the fauna and the environmental characteristics of a large set of high quality reference sites which can be used to predict the macroinvertebrate fauna to be expected at any site in the absence of pollution or other environmental stress. The observed fauna at new test sites can then be compared with their site-specific expected fauna to derive indices of ecological quality. All methodological decisions in any such model development have implications for the reliability, precision and robustness of any resulting indices for assessing the ecological quality and ecological grade (‘status’) of individual river stretches. The choice of reference sites and environmental predictor variables, the site classification and discrimination methods, the estimation of the expected fauna, and indices for comparing the agreement, or lack of it, between the observed and expected fauna, are all discussed. The indices are assessed on the reference sites and on a separate test set of 340 sites, which are subject to a wide range of types and degrees of impairment. 相似文献
602.
企业会计制度是企业会计核算工作的具体规范.通过对企业会计制度引发问题的思考,以进一步为企业会计制度设计的实效性奠定基础,也为企业会计制度改革提供了新的思维方式. 相似文献
603.
Catherine Meur-Férec 《Journal of Coastal Conservation》1997,3(2):121-132
In Europe, Britain was relatively early in being aware of the necessity of conserving natural coastal sites, though not as
early as The Netherlands. In the 1960s and 1970s, increasing economic and tourist pressures in Europe prompted measures geared
to the protection of other coasts in Europe. The promptness of the British reaction was a result of a sensitive public opinion
and of powerful private trusts (National Trust with Enterprise Neptune) rather than of a commitment by the Government. In
France a specific organization, in part inspired by the British principle, was set up. However, the French system is based
much more on a public authority, theConservatoire de l’Espace Littoral et des Rivages Lacustres and on legislation (Coastal Law of 1986). Although very different in the beginning, French and British conservation politics
today show many similarities, along with the similarities in the concerns of both countries. 相似文献
604.
605.
本文从会计数字游戏产生的根源着手,分析了上市公司会计数字游戏滋生的内、外部条件及诱因,进而分析如何才能够减少会计数字游戏. 相似文献
606.
由早中元古代中深变质岩系组成的华南加里东海盆基底及东海、南海古陆。元古代晚期,海盆在拉张环境下继续沉降,于震旦、寒武、奥陶纪期间,沉积了厚近两万米的地槽型火山-砂泥质建造,陆源碎屑主要来自东海、南海古陆,直到中生代晚期古陆才裂陷成海,始成今日的海陆分布格局。 相似文献
607.
IntroductionThenotionofsustainabledevelopmentwasproposedintheWorldConservationStrategy(IUCN,1980).Itispointedoutthattheconservationandthesustainabledevelopmentaremutuallydependentandtheyshouldbeintegrated,wheretheconservationmeansthemanagementofhuman… 相似文献
608.
A new environmental paradigm has emerged, reflecting a change in the public's understanding of resource sustainability. Forest
policy makers need to be better informed about such changes to achieve economic, social, and environmental objectives in a
manner that balances human needs and aspirations with ecosystem constraints. As an aid to this task, a forest resource accounting
system based on the key concept of natural capital could help reshape forest policies to provide an even wider spectrum of
benefits for both present and future generations by maintaining and enhancing the productive capacity of forest capital. Such
a resource accounting system would provide a tool for integrating multidimensional information requirements in measuring the
health of both forest ecosystems and economic systems. This paper outlines some of the features of this accounting system
and proposes and framework that would integrate economic and ecological characteristics of natural resources. Forest resource
accounting is urgently needed to achieve the sustainability goals of ecosystem management. 相似文献
609.
Ernest M. Thiessen Daniel P. Loucks 《Journal of the American Water Resources Association》1992,28(1):163-177
ABSTRACT: Since the early 1970s, a large volume of literature has accumulated related to multiobjective water resources management problems. A relatively small portion of this specifically addresses the negotiation process required when there are multiple decision makers with conflicting objectives. This paper focuses on that process and describes a computer program designed to assist such negotiation processes. This interactive computer assisted negotiation support system is called ICANS. ICANS is designed for dynamic, multi-issue, multi-party negotiation problems. Based on information provided in confidence by each party via an interactive graphical interface, the program can help determine if there exist any possible alternatives that are equivalent or even preferred to each party's decision in the absence of a negotiated agreement. If such alternatives exist, through a series of iterations in which each party's input data, assumptions, and preferences may change, ICANS can assist the parties in their search for a mutually acceptable and preferred agreement. A simple example illustrates the data requirements and the use of ICANS in negotiation experiments. 相似文献
610.
In this research we explored how the concepts and approaches of ecosystem services are currently used in water management in Europe, in the application of River Basin Management Plans (RBMP) developed for the EU Water Framework Directive (WFD). Five case studies have been considered, located in the River Basin Districts of the Po river (Italy), Scotland (United Kingdom), Scheldt river (Belgium), Danube river (Romania), Sado and Mira rivers and Ribeiras do Algarve (Portugal). These cases represent different regional contexts of application of this EU water policy, with specific socio-economic drivers and environmental issues. Each case study has developed an operational framework to analyse ecosystem services in practice together with a group of local stakeholders. In each regional case, we examined how EU water policy and RBMPs are implemented, considered legal and planning instruments from the national to the local scale, and we analysed the use of ecosystem service terms and concepts in the relevant planning instruments. In parallel, we explored the view of local stakeholders and water managers on the topic, collecting their opinion on three major aspects: the usefulness of the concepts and approaches of ecosystem services for WFD river basin management plans, the risks and benefits of their use, and the knowledge needs to put the concepts into practice. The major drawback of the ecosystem service approach seems to be the challenge for practitioners of understanding new concepts and methodologies, while the major advantages are that it highlights all the hidden benefits of a water body in good health and promotes multi-functionality and sustainability in water management. The results of this study provide a picture across Europe of the current use of the concepts of ecosystem services in the RBMP and relevant insight on the opinion of local stakeholders and water managers. 相似文献