Limits to agricultural growth in the Sistan Closed Inland Delta,Iran

The Sistan Delta in Iran is located at the end of a closed basin with nearly 100% of the supply coming from Afghanistan. This supply is supporting irrigated agriculture in the area and is the source for the lake system around the delta. These Hamoun lakes are ecological very valuable wetlands; a number of them are registered as Ramsar sites. The Iranian government tries to improve the living conditions of the people in the area, among others by providing infrastructure for irrigated agriculture. Further development of the irrigated area will mean less water for the Hamouns with resulting lower average water coverage of the lakes. This will not only endanger the ecosystem that the Hamouns support but also the livelihoods of the people that depend on the goods and services that the lakes provide. This paper describes a study that has been carried out to support decision making on potential development schemes in the delta. The non-availability of data from Afghanistan requires the development of various tools and the use of remote sensing techniques to enable to make estimates for the river flow that Iran can expect from Afghanistan. An IWRM approach has been used for the balancing of interests involved. Some preliminary conclusions are described.     

石首市天鹅洲湿地资源保护与生态旅游开发

湿地是地球上水陆相互作用形成的独特生态系统,是重要的生存环境和自然界最具生物多样性的生态景观之一,具有巨大的生态效益、社会效益和经济效益,也为生态旅游提供了得天独厚的自然条件。以保护湿地资源为前提,结合天鹅洲湿地自然保护区的保护与开发现状,提出了保护与生态旅游开发的策略。     

西藏巴结湿地生态系统特征及其保护对策

通过对水文、土壤、植被、动物等方面的野外调查、测量和试验研究,探讨了湿地生态特征和退化机理,并提出了加强西藏林芝地区湿地生态系统的保护对策。     

武汉市湿地主要环境问题及保护对策

武汉市湿地资源丰富,城市的快速发展给这些湿地生态系统带来了诸多威胁,主要表现在：面积萎缩、水质污染加剧、生物多样性下降、可利用水资源减少等方面,提出了加强湿地资源可持续利用和保护的对策措施。     

鄱阳湖湿地保护与合理利用

对鄱阳湖湿地环境与资源的现状进行了概述,从环境与资源状况,立法、管理与资源合理利用,以及湿地研究、监测与宣传教育等3个方面分析鄱阳湖湿地目前存在的问题及引起这些问题原因.针对这些问题,提出鄱阳湖湿地保护与合理利用对策.考虑到立法在鄱阳湖湿地保护管理中的重要性,对<江西省鄱阳湖湿地保护条例>进行了较为深入的剖析和探讨.由于生态旅游是保护鄱阳湖湿地资源合理利用的最有效途径,因此,对生态旅游也进行了较为详细的介绍.     

湿地与水患关系之研究

湿地是地球上水陆相互作用形成的具有独特生态功能的景观类型，在控制洪水、滞留洪峰、调节河川径流、补充地下水、净化水体、防预温室效应和维持区域水平衡中发挥着极其重要的作用。一方面，湿地生态系统遭到破坏容易引发系列水患。另一方面，频繁水患又对湿地生态系统产生严重危害，引起一系列的生态问题。维持湿地数量质量、面积容积、自净功能、自然属性、“海绵体”作用是防治水患的最有效措施，也迫在眉睫。     

湿地资源遥感动态监测和管理应用综述

结合近期湿地遥感技术和湿地资源管理系统发展动态,从湿地资源监测、变化、演替、管理应用等方面国内外研究现状进行了湿地资源遥感动态监测和管理应用的全面论述和总结,并指出目前存在一些不足和未来发展趋势中的5个重点研究内容。     

Efficacy of constructed wetlands for removal of bacterial contamination from agricultural return flows

Water quality degradation from bacterial pathogens is one of the leading causes of surface water impairment in California agricultural watersheds. In the San Joaquin Valley, approximately 50 and 100% of water samples collected from three different irrigation return flows exceeded the Escherichia coli standard of 126 cfu 100 mL⁻¹ and the enterococci standard of 33 cfu 100 mL⁻¹, respectively, as required for water discharge into state waterways. These results show that runoff from irrigated crops can contribute a significant load of bacteria indicators and potentially pathogenic microorganisms to waterways. Constructed wetlands are gaining recognition as a management practice for use in irrigated agriculture to reduce bacterial loads and a wide variety of water quality contaminants in agricultural return flows prior to discharge into waterways. Based on input-output sampling of four wetlands, 66-91% of E. coli concentrations and 86-94% of enterococci concentrations were retained in the wetlands. Removal efficiencies in terms of bacteria load were even higher, 80-87% and 88-97% for E. coli and enterococci, respectively, due to water losses (seepage and evapotranspiration) within the wetland. Of all the parameters considered, hydraulic residence time (HRT) appeared to be the factor having the greatest effect on the efficiency of bacteria indicator removal. Remarkably, a HRT of less than a day can achieve considerable bacteria indicator retention (∼70%), which allows for relatively small wetland areas being able to treat runoff from large agricultural areas (up to 360:1 in this study).     

Influence of nitrogen on atrazine and 2, 4 dichlorophenoxyacetic acid mineralization in blackwater and redwater forested wetland soils

 Microcosms were used to determine the influence of N additions on active bacterial and fungal biomass, atrazine and dichlorophenoxyacetic acid (2,4-D) mineralization at 5, 10 and 15 weeks in soils from blackwater and redwater wetland forest ecosystems in the northern Florida Panhandle. Active bacterial and fungal biomass was determined by staining techniques combined with direct microscopy. Atrazine and 2,4-D mineralization were measured radiometrically. Treatments were: soil type, (blackwater or redwater forested wetland soils) and N additions (soils amended with the equivalent of 0, 200 or 400 kg N ha^–1 as NH₄NO₃). Redwater soils contained higher concentrations of C, total N, P, K, Ca, Mn, Fe, B and Zn than blackwater soils. After N addition and 15 weeks of incubation, active bacterial biomass in redwater soils was lower when N was added. Active bacterial biomass in blackwater soils was lower when 400 kg N ha^–1, but not when 200 kg N ha^–1, was added. Active fungal biomass in blackwater soils was higher when 400 kg N ha^–1, but not when 200 kg N ha^–1, was added. Active fungal biomass in redwater soils was lower when 200 kg N ha^–1, but not when 400 kg N ha^–1, was added. After 15 weeks of incubation 2,4-D degradation was higher in redwater wetland soils than in blackwater soils. After 10 and 15 weeks of incubation the addition of 200 or 400 kg N ha^–1 decreased both atrazine and 2,4-D degradation in redwater soils. The addition of 400 kg N ha^–1 decreased 2,4-D degradation but not atrazine degradation in blackwater soils after 10 and 15 weeks of incubation. High concentrations of N in surface runoff and groundwater resulting from agricultural operations may have resulted in the accumulation of N in many wetland soils. Large amounts of N accumulating in wetlands may decrease mineralization of toxic agricultural pesticides. Received: 26 June 1998     

湿地生态系统服务功能及其恢复与保护对策

湿地是地球上一种重要的生态系统,具有多种生态服务功能。本文在介绍湿地生态系统各项服务功能、湿地退化原因及恢复理论的前提下,提出湿地恢复与保护相应对策,对湿地资源可持续利用和湿地恢复与重建具有重要意义。