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61.
The paper describes the local, national, European and wider-area framework, statutes, and formal and voluntary mechanisms for managing European estuaries. These aspects are discussed in relation to two large and representative estuarine systems, the Tagus, Portugal, and the Humber, on the English North Sea coast As estuaries are sites of many activities and uses, most of which are encouraged or at least condoned, management has the role of preventing and resolving conflicts between those uses and users. Accepted uses of estuaries include the discharge and dumping of waste materials, fin and shell-fisheries, conservation, land reclamation, natural usage, abstraction by industry, and recreation. Estuarine management is now being carried out within the constraints of local and regional government planning, planning and activities of water pollution control bodies, fisheries control bodies, and navigation and port authorities The Tagus and Humber estuaries support all of the above activities and uses, and have controls within a European legislative framework but have differing histories of management and planning in order to resolve conflicts. In addition the Humber is subject to controls placed on North Sea areas. The paper discusses the relevant national and European legislation (Directives) and accepted practices for management. Furthermore, the paper discusses the formulation and practice of estuarine management plans as used by various bodies (nature conservation, water quality and regional authority). It is of particular note that the lessons from these two estuaries are relevant to many other European estuaries. 相似文献
62.
水稻主要病虫综合防治专家系统—系统外壳的研制 总被引:4,自引:0,他引:4
按照国家八五项目要求,以水稻病虫害管理知识为背景,笔者构建了水稻主要病虫综防专家系统外壳(ESRIPM).并初步建立了珠江三角洲稻区主要害虫综合防治专家系统,系统中提出一种知识的组织方法,成功地把模型引入专家系统中.本系统具有知识编辑、咨询、专家系统;系统维护、4个一级子系统,系统中已装入三化螟,稻飞虱,稻纵卷叶螟等害虫综防管理的知识,并通过调试.本系统采用下拉式菜单,人机界面友好,操作简单.此专家系统外壳也适用建立其它各种害虫管理的专家系统. 相似文献
63.
植物定植图微机显示与管理系统 总被引:1,自引:0,他引:1
介绍了运用软件工程的方法和数据库技术研究开发的南京中山植物园植物定植图微机显示与管理系统。详细介绍了系统的目标,系统的实现,应用软件的研制及应用效果。 相似文献
64.
Abstract. Goat grazing is examined as a possible tool for grassland management. In this paper, goat grazing preferences are described. The proportion of biomass of particular species eaten by a goat was estimated on the basis of comparison of paired quadrats. The control quadrats were clipped before grazing and their biomass was compared with the biomass in grazed quadrats. Estimates of the proportion consumed were calculated for frequent species; they were significantly different among species; the most preferred species was Polygonum bistorta, a species with broad, soft, nutritious leaves. The least grazed species were Agrostis tenuis and Galium harcynicum. Various indices of food selectivity (e.g. forage ratio, electivity index) were calculated and their behaviour was compared. Canonical Correspondence Analysis and Redundancy Analysis with appropriate covariates reflecting the block design of the experiment were used to evaluate overall changes in species composition and yielded results similar to those from the direct estimation of the proportion consumed. 相似文献
65.
66.
P. R. Burbridge 《Hydrobiologia》1994,285(1-3):311-322
Freshwater habitats play a very important role in sustaining human activities. Natural functions of wetlands, and other freshwater habitats, generate a wide array of resources that directly or indirectly support the economic and social welfare of diverse groups of people. This role is being seriously weakened as a result of inappropriate planning and management approaches which fail to maintain the functional integrity of the freshwater ecosystems with the result that the flow and quality of resources is degraded. This paper illustrates some of the major functions of wetlands and presents a case for developing integrated planning and management practices that protect the health and productivity of freshwater wetlands and seek to optimise the sustainable use of the flows of resources they generate. 相似文献
67.
Insect resistance of transgenic plants that express modified Bacillus thuringiensis cryIA(b) and cryIC genes: a resistance management strategy 总被引:7,自引:0,他引:7
68.
长白山站的研究数据库管理系统翟永华,赵士洞(中国科学院沈阳应用生态研究所110015)Date-BaseManagementSysteminChangbaishanForestEcosystemResearchStation.¥ZhaiYonghua... 相似文献
69.
Abstract. We describe a model of heath vegetation, in which species were classified into five functional groups based on characteristics of their propagule pools, post-fire growth, timing and mode of reproduction and competitive status. The model assumes no recruitment without fire and a simple competitive hierarchy based on vertical stature. A critical feature of the model is an initial post-fire window of 5–6 yr in which competition from overstorey species on understorey species is reduced. Understorey functional groups differ in their ability to exploit this window. In the field, we tested five predictions derived from the model: (a) overall species richness of understorey varies inversely with overstorey density as a result of a trend in richness of woody species, but not in herbaceous species; (b) where an overstorey was present in the previous fire interval, post-fire population density is reduced in a functional group of understorey serotinous resprouting shrubs, but not in a group of understorey obligate-seeding shrubs with soil seed banks; (c) in understorey serotinous resprouting shrubs, post-fire regrowth in resprouting individuals is adversely affected by the presence of an overstorey in the preceding fire interval; (d) in understorey serotinous resprouting shrubs, levels of pre-fire propagules are lower in the presence of an overstorey, reducing the density of post-fire recruits; and (e) in understorey serotinous resprouting shrubs, recruitment relative to the pre-fire population is unaffected by overstorey species within the window of reduced competition. Of these, three tests (a,b,d) supported the model, one (e) may support the model, but the results were inconclusive and one (c) did not support the model. Limitations and further applications of the model are discussed. Our results suggest that maintenance of high densities of overstorey populations is in conflict with conservation of some understorey species. Models of the type we propose will help identify and resolve such conflicts and promote the judicious use of fire to maintain full species diversity of plant communities. 相似文献
70.
Marjorie M. Holland 《Hydrobiologia》1993,251(1-3):331-340
Evidence suggests that the boundaries between rivers, floodplain wetlands, and adjacent upland communities are among the most important components of landscapes. In a landscape context, floodplain wetlands and their ecotones are important transition zones between uplands and aquatic ecosystems. Management of wetland patches and ecotones to achieve sustainable ecosystems requires action on a broad scale, giving consideration to all factors affecting wetlands and the drainage basins of which they are a part. In northeastern United States, a struggle to identify new sources of water has focussed attention on the sustainability of aquatic ecosystems. 相似文献