Past On-Site Experience,Crowding Perceptions,and Use Displacement of Visitor Groups to a Peri-Urban National Park

Past on-site experience was linked to the crowding perceptions and use displacement of 383 on-site visitors to the peri-urban Danube Floodplains National Park, Austria. Three visitor groups were determined according to their area experience: local residents from Vienna and rural communities, having the highest level of experience; regional visitors from the city and eastern Austria; and tourists from Austria and abroad with the lowest degree of experience. Crowding perceptions were significantly different across the user groups. More than 50% of local residents perceived the national park as crowded, whereas only 27% of regional visitors and 19% of tourists reported such an evaluation. Even among local residents and regional visitors, respondents with more on-site experience expressed a greater impression of a crowded park. Differences in crowding evaluations between local rural and urban residents and between regional rural and urban visitors were not found. For 27% of local residents and 15% of regional visitors, use levels were so unacceptable that they displaced temporally and spatially, whereas use displacement was relatively irrelevant for tourists. The use displacement strategies involved differ among the three user groups. Management implications were discussed, taking the specific situation of the small national park on the urban-rural fringe into consideration.     

Regional environmental assessment (REA) and local Agenda 21 implementation

The implementation of sustainable development requires several support instruments. One of the major instruments in the Rio Declaration to support this process has been environmental assessment that has been given considerable emphasis as to its potential ability to help achieve more sustainable forms of development. Regional environmental assessment (REA) has shown to be effective in supporting local sustainable development process. Selected environmental assessment methods have been␣used to improve the REA exercise and provide reliable data for decision-making not only to correct environmental problems due to past unsustainable social-economic developments but also help local governments to implement Agenda 21 (AG21) plans and projects.     

综合防治棉铃虫的区域性技术体系研究

研究改进了棉铃虫中期预报方法；提出“一代监测、二代保顶、三代保蕾、四代保铃”为主的防治策略；研究制定适用于不同世代、不同水肥条件的科学防治指标，协调应用多种配套措施保护、利用自然天敌控害，系统监测和治理棉铃虫抗药性；利用棉花种质资源和品种的抗病、抗虫性；诱杀成虫；组建大面积综防技术体系。在１９９２～１９９５年棉铃虫猩獗发生的情况下，于河南省新乡县棉花病虫害综防示范区大面积实施后，有效控制了棉铃虫危害。     

REGIONAL WATER QUALITY MANAGEMENT BY THE GENERALIZED REDUCED GRADIENT METHOD1

ABSTRACT: A river basin-wide water quality management system is considered. The river receives thermal as well as organic wastes. At-source treatment of these pollutants is imposed to control the basin-wide water quality. The related water quality standards are: the minimum DO concentration, the maximum allowable BOD concentration, the maximum allowable stream temperature, and the allowable rise in stream temperature. The general dynamic mathematical model representing water quality in streams and the thermal effects on BOD and DO concentrations is presented. The model is highly nonlinear in nature. The optimal management problem involving the model is solved by a recently developed nonlinear propgramming technique - the generalized reduced gradient (GRG) method. Comparison of results obtained by the GRG method vs. dynamic programming, and of results using a more realistic mathematical model vs. a simple model are presented. The analysis procedure can be applied to designing new and examining existing water quality programs, and to study the influence of alternate policies and constraints.     

区域自然灾害系统基本单元研究-Ⅱ:应用部分——湖南省综合农业灾情区域分异规律

本文应用灾害系统基本单元理论,以湖南省农业自然灾害为例,在地理信息系统支持下,将湖南省农业自然灾害系统划分为３２５２４个基本单元。进而,以民政部１９７８～１９９３年农业灾情统计数据为标准,通过多因子逐步回归的方法,建立了反映湖南省多年平均状况的五种主要农业灾害灾情模型。最后,以灾害基本单元为最小空间分异单位,对综合农业灾情分异规律进行了探讨,并首次提出了基于自然单元的湖南省综合农业灾情的分异规律首先是受地势控制的东西分异的主要结论。     

ENVIRONMENTAL AUDITING: A Synoptic Approach for Assessing Cumulative Impacts to Wetlands

/ The US Environmental Protection Agency's Wetlands ResearchProgram has developed the synoptic approach as a proposed method forassessing cumulative impacts to wetlands by providing both a general and acomprehensive view of the environment. It can also be applied more broadly toregional prioritization of environmental issues. The synoptic approach is aframework for making comparisons between landscape subunits, such aswatersheds, ecoregions, or counties, thereby allowing cumulative impacts tobe considered in management decisions. Because there is a lack of tools thatcan be used to address cumulative impacts within regulatory constraints, thesynoptic approach was designed as a method that could make use of availableinformation and best professional judgement. Thus, the approach is acompromise between the need for rigorous results and the need for timelyinformation. It is appropriate for decision making when quantitative,accurate information is not available; the cost of improving existinginformation or obtaining better information is high; the cost of a wronganswer is low; there is a high demand for the information; and the situationcalls for setting priorities between multiple decisions versus optimizing fora single decision. The synoptic approach should be useful for resourcemanagers because an assessment is timely; it can be completed within one totwo years at relatively low cost, tested, and improved over time. Anassessment can also be customized to specific needs, and the results arepresented in mapped format. However, the utility of a synoptic assessmentdepends on how well knowledge of the environment is incorporated into theassessment, relevant to particular management questions.KEY WORDS: Cumulative impact assessment; Landscape ecology; Regionalprioritization     

Comparing theoretical and actual feasibility of transferring management of river lift irrigation systems in Sudan

This article focuses on agricultural production in lift irrigation schemes along the White Nile in the Sudan. A comparison is drawn between the theoretical forecast and actual practical experience regarding the feasibility of transferring management from government-run parastatal organizations to private farmer organizations. Although the theoretical model indicates that farmers should be able to cover the cost of managing the river lift irrigation systems, field data show, however, that farmers growing wheat are barely able to break even. Even assuming a doubling of the present wheat yields, the cash surplus earned would only suffice for fuel to operate the pumps. Under these circumstances, it is not surprising that, contrary to government expectations, the private sector has been unenthusiastic about taking over management of White Nile river lift schemes. The lessons that emerge from this study indicate that unplanned and rapid withdrawal of state management can lead to negative results. The transfer of management responsibility for the river pumps does not appear to influence economic performance considerably, which depends on the wider context of the country's economic, political and institutional environment, within which the agricultural sector functions.     

山西省自然灾害的区域经济评价

以区域经济学为基础，灾害学为主导，应用层次分析原理，分析了山西省自然灾害对区域经济发展的影响，评价了不同区域的灾害严重程度及主要灾种，将全省划分为五大灾害经济区，为区域生产力布局提供了一些科学理论依据．     

近五年中国自然灾害空间分布格局及其月动态变化研究

作者根据《中国减灾》所载１９９０～１９９４年月灾情记录，经统一编码和标准化处理，建立了以行政县为基本单元的数据库。进而对近五年来中国自然灾害空间分布及其月动态变化进行分析，并与１９４９～１９９０年中国自然灾害的平均状况进行对比。     

流域性洪涝及其指标研究

本文讨论了区域洪涝指标，认为区域洪涝指标应反映出不同洪涝面积和不同洪涝等级对区域洪涝的影响程度，基于这一思想，提出了一个区域洪涝指标计算公式。为了使区域洪涝研究更为具体和可比，本文在分析区域洪涝指标的基础上，提出了流域性洪涝的概念，并以《中国近五年百旱涝分布图集》为基础，建立了淮河流域５００年流性洪涝指标序列及其等级。