沈阳卧龙湖湿地的保护措施

卧龙湖是辽宁西北半干旱区向中部平原湿润区过渡的生态敏感带,本文介绍了卧龙湖的历史与现状,分析了存在的主要问题,并从微观角度提出了保护卧龙湖湿地的具体措施。     

基于RS/GIS的大辽河口湿地景观格局时空变化研究

基于1988、1995、2001和2007年的四期TM数据,应用GIS/RS技术与景观格局分析软件FRAGSTATS,定量分析大辽河口地区湿地景观格局的动态变化。结果表明,自1988年以来,大辽河口地区的湿地面积逐年增加,湿地景观多样性指数和均匀度指数呈现先降后升的趋势,景观破碎化程度增强。湿地类型变化主要表现在大量的自然湿地转化为人工湿地或人工景观,具体表现在转化为建筑用地、水稻田、养殖区。1988~1995年期间,大辽河口地区的环境质量下降,该地区生物生活环境的多样性降低,造成了一些物种种群数量的减少甚至消失;但是自1995年以后,该地区的景观多样性和均匀性升高,抗干扰能力增强,环境质量有所提高。研究区湿地景观格局的动态变化主要是受自然条件和人为活动干扰共同作用的结果。     

Wetland management: an analysis of past practice and recent policy changes in Ontario

The Ontario Government has recently released its latest Provincial Policy Statement (PPS), which includes a policy concerning wetland protection. This paper uses interviews with key respondents and the results of three separate case studies that examined the former PPS in order to assess the ability of the new policy to improve wetland conservation efforts in Ontario. The case studies include wetland conservation and urban stormwater management in the City of London for the periods 1978-1999 and 1978-2000, respectively. As well, agricultural drainage that occurred in the Township of Zorra for the period 1978-1997 is used to address this management dimension. While progress is evident, the current policy will be difficult to implement effectively because it inadequately deals with the fundamental aspects of management: fragmented jurisdiction, interagency communication, financial arrangements, enforcement, and promoting informed decision making.     

Modeling wetland loss in coastal Louisiana: Geology,geography, and human modifications

Habitat change in coastal Louisiana from 1955/6 to 1978 was analyzed to determine the influence of geological and man-made changes on landscape patterns within 7.5 min quadrangle maps. Three quantitative analyses were used: principal components anlaysis, multiple regression analysis, and cluster analysis.Regional differences in land loss rates reflect variations in geology and the deltaic growth/decay cycles, man-induced chages in hydrology (principally canal dredging and spoil banking), and land-use changes (principally urbanization and agricultural expansion). The coastal zone is not homogeneous with respect to these variables and the interaction between causal factors leading to wetland loss is therefore locally variable and complex.The relationship between wetland loss, hydrologic changes, and geology can be described with statistically meaningful results, even though these data are insufficient to precisely quantify the relationship. However, these data support the hypothesis that the indirect impacts of man-induced changes (hydrologic and land use) may be as influential as the direct impacts resulting in converting wetlands to open water (canals) or modified (impounded) habitat.Three regions within the Louisiana coastal zone can be defined, based on the potential causal factors used in the analyses. The moderate (mean = 22%) wetland loss rates in region 1 are a result of relatively high canal density and developed area in marshes which overlie sediments of moderate age and depth; local geology acts, in this case, to lessen indirect impacts. On the other hand, wetland loss rates in region 2 are high (mean = 36%), despite fewer man-induced impacts; the potential for increased wetland loss due to both direct and indirect effects of man's activity in these areas is high. Conversely, wetland loss (mean = 20%) in region 3 is apparently least influenced by man's activity in the coastal zone because of sedimentary geology (old, thin sediments), even though these areas have already experienced significant direct habitat alteration and wetland loss.     

中国湿地现状综述

湿地是重要的自然资源,对人类生存起着重要作用。本文综述了湿地的含义、功能与 价值、中国湿地的特点与现状,以促进中国湿地的可持续发展与利用。     

我国湿地保护的存在问题及法律对策

湿地是重要的自然资源之一,保护湿地对于生态环境有着极其重要的作用,然而湿地的法律保护在我国却是一个薄弱环节。本文论述了我国湿地保护中存在的若干问题,并提出具体的法律对策——制定《湿地保护法》。     

Visitor-induced changes in the chemical composition of soils in backcountry areas of Mt Robson Provincial Park, British Columbia, Canada

Balancing recreation and conservation is an important issue in Canada's parks and protected areas. Increased levels of visitation to parks, especially to backcountry areas, create undue pressure on natural resources, resulting in a variety of ecological impacts. This paper illustrates the issue of visitor-induced changes on the chemical composition of soils in Mt Robson Provincial Park, British Columbia. Soil samples were collected from dish wash stations and fire pits (disturbed sites) at seven campgrounds located along two popular backcountry trails, and were compared to samples obtained from adjacent undisturbed control sites. Analysis of soil samples suggest that the lower amounts of aluminum, potassium, magnesium and sodium in many of the 'disturbed' samples can be related to intense leaching in dish wash stations, and can be attributed to frequent disposal of waste water from washing and cooking activities. Soils in wash stations generally had higher phosphorus, copper and zinc contents as compared to controls. Soils in fire pits were elevated in copper, relative to controls. Results of this study support park regulations that waste water disposal and camp fires be restricted to designated areas. Informing the public of scientific studies helps them understand the consequences of their activities; this may help persuade them to observe park rules and regulations.     

春夏两季四种植物净化生活污水的静态试验研究

在春夏两季,分别开展为期30天的静态试验,以研究芦苇、黄菖蒲、美人蕉、香蒲四种湿地植物对富营养化生活污水的净化效果。试验结果表明：通过纵向比较,夏季时植物对TN、TP的净化效果优于春季。通过横向比较,春季时黄菖蒲和香蒲的净化能力较强;夏季时美人蕉的净化能力较强。在时间上,可将喜温植物与耐寒植物结合,以保证湿地系统的长年运行;在空间上,可将挺水植物与沉水植物结合,以保证湿地系统的处理效果。     

Impacts of freshwater wetlands on water quality: A landscape perspective

In this article, we suggest that a landscape approach might be useful in evaluating the effects of cumulative impacts on freshwater wetlands. The reason for using this approach is that most watersheds contain more than one wetland, and effects on water quality depend on the types of wetlands and their position in the landscape. Riparian areas that border uplands appear to be important sites for nitrogen processing and retention of large sediment particles. Fine particles associated with high concentrations of phosphorus are retained in downstream wetlands, where flow rates are slowed and where the surface water passes through plant litter. Riverine systems also may play an important role in processing nutrients, primarily during flooding events. Lacustrine wetlands appear to have the least impact on water quality, due to the small ratio of vegetated surface to open water. Examples are given of changes that occurred when the hydrology of a Maryland floodplain was altered.     

Ecologically derived guidelines for managing two New Zealand lakes

Lakes Manapouri and Te Anau, in Fiordland National Park, became the center of a major controversy after the New Zealand government offered their water resource to an overseas aluminum smelting consortium for electricity generation. Although the scheme proceeded, the lake levels were not raised as originally proposed. Rather, government sought guidelines to optimize hydroelectric potential while maintaining ecological stability of the vulnerable, largely forested, glaciated lakeshores. Guidelines were derived by relating the vegetation zonation to the natural lake-level fluctuations recorded daily for 37 years. Ahigh operating range in the upper third of the lakes' natural ranges, based on flood tolerances of the woody shoreline species, restricts both duration and frequency. Alow operating range (ca. lower third) safeguards stability of shoreline sediments by limiting drawn-down rates, duration, and frequency. Themain operating range (ca. middle third) has few limitations. These guidelines, which allow utilization of ca. 93% of the water resource, have now been verified by instances of flooding and draw-down rates that exceeded the natural rates recorded earlier. The guidelines were officially accepted by the government in 1977 as a basis for managing the valuable multiple resources of these two lakes and their environs, and they were formalized in legislation in 1981. The details and merits of the guideline approach are discussed.