PROFILE: Risk Assessment as an Environmental Management Tool: Considerations for Freshwater Wetlands

/ This paper presents a foundation for improving the risk assessmentprocess for freshwater wetlands. Integrating wetland science, i.e., use of anecosystem-based approach, is the key concept. Each biotic and abiotic wetlandcomponent should be identified and its contribution to ecosystem functionsand societal values determined when deciding whether a stressor poses anunreasonable risk to the sustainability of a particular wetland.Understanding the major external and internal factors that regulate theoperational conditions of wetlands is critical to risk characterization.Determining the linkages between these factors, and how they influence theway stressors affect wetlands, is the basis for an ecosystem approach.Adequate consideration of wetland ecology, hydrology, geomorphology, andsoils can greatly reduce the level of uncertainty associated with riskassessment and lead to more effective risk management. In order to formulateeffective solutions, wetland problems must be considered at watershed,landscape, and ecosystem scales. Application of an ecosystem approach can begreatly facilitated if wetland scientists and risk assessors work together todevelop a common understanding of the principles of both disciplines.KEY WORDS: Ecological risk assessment; Freshwater wetlands;Environmental pollution; Chemical stressors; Physical stressors; Biologicalstressors     

Biological Effects of Fine Sediment in the Lotic Environment

/ Although sedimentation is a naturally occurring phenomenon inrivers, land-use changes have resulted in an increase in anthropogenicallyinduced fine sediment deposition. Poorly managed agricultural practices,mineral extraction, and construction can result in an increase in suspendedsolids and sedimentation in rivers and streams, leading to a decline inhabitat quality. The nature and origins of fine sediments in the loticenvironment are reviewed in relation to channel and nonchannel sources andthe impact of human activity. Fine sediment transport and deposition areoutlined in relation to variations in streamflow and particle sizecharacteristics. A holistic approach to the problems associated with finesediment is outlined to aid in the identification of sediment sources,transport, and deposition processes in the river catchment. The multiplecauses and deleterious impacts associated with fine sediments on riverinehabitats, primary producers, macroinvertebrates, and fisheries are identifiedand reviewed to provide river managers with a guide to source material. Therestoration of rivers with fine sediment problems are discussed in relationto a holistic management framework to aid in the planning and undertaking ofmitigation measures within both the river channel and surrounding catchmentarea.KEY WORDS: Sedimentation; Fine sediment; Holistic approach; Ecologicalimpact; River restoration     

Assessing Water Quality at Large Geographic Scales: Relations Among Land Use,Water Physicochemistry,Riparian Condition,and Fish Community Structure

Data collected from 172 sites in 20 major river basins between 1993 and 1995 as part of the US Geological Survey's National Water-Quality Assessment Program were analyzed to assess relations among basinwide land use (agriculture, forest, urban, range), water physicochemistry, riparian condition, and fish community structure. A multimetric approach was used to develop regionally referenced indices of fish community and riparian condition. Across large geographic areas, decreased riparian condition was associated with water-quality constituents indicative of nonpoint source inputs—total nitrogen and suspended sediment and basinwide urban land use. Decreased fish community condition was associated with increases in total dissolved solids and rangeland use and decreases in riparian condition and agricultural land use. Fish community condition was relatively high even in areas where agricultural land use was relatively high (>50% of the basin). Although agricultural land use can have deleterious effects on fish communities, the results of this study suggest that other factors also may be important, including practices that regulate the delivery of nutrients, suspended sediments, and total dissolved solids into streams. Across large geographic scales, measures of water physicochemistry may be better indicators of fish community condition than basinwide land use. Whereas numerous studies have indicated that riparian restorations are successful in specific cases, this analysis suggests the universal importance of riparian zones to the maintenance and restoration of diverse fish communities in streams.     

浅析景观格局分析方法在生态恢复当中的应用

退化生态系统的恢复是一项艰巨任务，它需要考虑到所要恢复的退化生态系统的结构，多样性和其动态的整体性和长期性。退化生态系统恢复所面临的挑战是理解和利用生态演替理论来完成并加速恢复进程。恢复的主要目标是建立一个自维持的，由不同的群落或生态系统组成的能够满足不同需要如生物保护和粮食生产需要的景观。景观生态学关注于大的空间尺度的生态学问题。景观生态学研究方法可以为退化生态系统恢复实践提供指导。在解决退化生态系统的恢复问题时，景观生态学的方法在理论和实践上是有效的。景观生态学中的核心概念和其一般原理斑块形状、生态系统间相互作用、镶嵌系列等都同退化生态系统的恢复有着密切的关系。如恢复地点的选择和适当的恢复要素的空间配置。在评价退化生态系统的恢复是否取得成功，利用景观生态学也具有重要的意义。景观生态学理论如景观格局与景观异质性理论，干扰理论和尺度理论都能够指导退化生态系统的恢复实践。同样地，景观生态学的许多研究方法对于生态恢复的方案确立、方法实施等都具有明确的指导意义。景观生态学思想与方法应用于退化生态系统恢复过程是一种新的有效途径。     

县级生态示范区建设的几点思考

文章分别从内容、对策和措施、实施主体等三方面全面论述了生态示范县建设的内涵,分析了海安县建设生态示范县的重要性,结合海安县实际,突出海安特色,探讨了建设生态示范县的重点应放在生态农业建设、生态工业建设、生态城镇建设、农村五禁工程、生态文化建设等上,提出了相应的行政、法律、经济、技术保障措施以推动示范县的建成.     

区域环境影响评价中土地使用生态适宜性分析

以大连保税区和出口加工区为例分析了区域环境影响评价中土地使用生态适宜性 ,引入了环境适宜性评价指标 ,通过绘制区域的分区位势图来指导区域的规划布局 ,探讨了区域环评中生态适宜性分析的方法     

生态优先原则在通州新城建设过程中的应用

为了协调类似城市间的发展,促进区域统筹,引导其有序竞争,构建和谐的社会,以通州与南通两城市为例,积极引入生态优先的思想来处理两城市的职能关系、空间关系、环境保护以及其他可持续发展问题,力求扬长避短,节约发展成本,促进有序城市组群空间的形成,实现跨区域协调发展。     

论“人与自然和谐共处”的思想

环境道德和生态伦理主张“人与自然和谐共处”的思想，与“人类中心主义”和“自然中心主义”有着本质区别。对当代环境道德和生态伦理的特征与主张应准把握，其将自然原理和人道原理结合起来，由人及物将非人生命体或自然作为人的“伙伴与朋友”。     

长乐市生态建设体系构想

分析了长乐市建设国家级生态城市的紧迫性、必要性和可行性，为实现长乐生态效益型经济可持续发展战略选择提供参考。     

关于建设重庆市黔江生态区的思考

建设生态城市是时代所趋，本文探讨了建设重庆市黔江生态区的必要性与可行性，提出了建设目标与思路，明确了战略与重点，并以提高认识，统一规划，优惠政策，加强环保，依靠科技，增大投入，依法治区，突出重点，强化宣教，加强领导，严格考核等方面提出了对策，这对于建设生态区，生态城市具有现实意义。