"3S"技术在生态环境动态监测中的应用研究

针对传统生态环境动态监测方法的不足,论述了"3S"技术的特点与优势,并结合"四川省岷江中上游生态环境遥感综合调查与评价"项目,介绍了应用"3S"技术进行生态环境动态监测的方法和流程.  

基于RS、GIS的城市绿地生态效益评价与预测模型

以遥感(RS)信息作为主要的数据来源,结合其他实地监测和统计数据,采用GIS技术进行数据分析和处理,建立城市绿地生态效益评价与预测模型,为城市绿地规划、改善城市生态环境提供定量化的科学依据。  

A Landscape Approach for Detecting and Evaluating Change in a Semi-Arid Environment

Vegetation change in the American West has been a subject of concern throughout the twentieth century. Although many of the changes have been recorded qualitatively through the use of comparative photography and historical reports, little quantitative information has been available on the regional or watershed scale. It is currently possible to measure change over large areas and determine trends in ecological and hydrological condition using advanced space-based technologies. Specifically, this process is being tested in a community-based watershed in southeast Arizona and northeast Sonora, Mexico using a system of landscape pattern measurements derived from satellite remote sensing, spatial statistics, process modeling, and geographic information systems technology. These technologies provide the basis for developing landscape composition and pattern indicators as sensitive measures of large-scale environmental change and thus may provide an effective and economical method for evaluating watershed condition related to disturbance from human and natural stresses. The project utilizes the database from the North American Landscape Characterization (NALC) project which incorporates triplicate Landsat Multi-Spectral Scanner (MSS) imagery from the early 1970s, mid 1980s, and the 1990s. Landscape composition and pattern metrics have been generated from digital land cover maps derived from the NALC images and compared across a nearly 20-year period. Results about changes in land cover for the study period indicate that extensive, highly connected grassland and desertscrub areas are the most vulnerable ecosystems to fragmentation and actual loss due to encroachment of xerophytic mesquite woodland. In the study period, grasslands and desertscrub not only decreased in extent but also became more fragmented. That is, the number of grassland and desertscrub patches increased and their average patch sizes decreased. In stark contrast, the mesquite woodland patches increased in size, number, and connectivity. These changes have important impact for the hydrology of the region, since the energy and water balance characteristics for these cover types are significantly different. The process demonstrates a simple procedure to document changes and determine ecosystem vulnerabilities through the use of change detection and indicator development, especially in regard to traditional degradation processes that have occurred throughout the western rangelands involving changes of vegetative cover and acceleration of water and wind erosion.  

Desertification Evaluated Using an Integrated Environmental Assessment Model

Desertification has been defined as land degradation in arid, semi-arid and dry sub-humid areas resulting from various factors, including climatic variations and human activities (United Nations, 1992). A technique for identifying and assessing areas at risk fordesertification in the arid, semi-arid, and subhumid regionsof the United States was developed by the Desert Research Institute and the U.S. Environmental Protection Agency (EPA), using selected environmental indicators integrated into a Geographic Information System (GIS). Five indicators were selected: potential erosion, grazing pressure, climatic stress (expressed as a function of changesin the Palmer Drought Severity Index [PDSI]), change invegetation greenness (derived from the Normalized DifferenceVegetation Index [NDVI]), and weedy invasives as a percentof total plant cover. The data were integrated over aregional geographic setting using a GIS, which facilitateddata display, development and exploration of data relationships, including manipulation and simulation testing. By combining all five data layers, landscapes having a varying risk for land degradation were identified, providing a tool which could be used to improve landmanagement efficiency.  

A Landscape Ecology Assessment of the Tensas River Basin

A group of landscape ecological indicators were applied to biophysical data masked to the Tensas River Basin. The indicators were used to identify and prioritize sources of nutrients in a Mississippi/Atchafalaya River System sub-basin. Remotely sensed data were used for change detection assessment. With these methods, we were able to look at land use practices over the past twenty years in the Tensas River Basin of Louisiana. A simple land use classification was applied to multispectral scanner (MSS) data from 1972 and 1991. The landscape analysis methods described in this paper will show how to use these methods to assess the impact of human land use practices that are being implemented to improve environmental quality. Landscape assessment methods can be used as a simple, timely, cost effective approach for monitoring, targeting, and modeling ecosystem health in watersheds. Although this study was conducted in the southeast, the methods described in this paper may be applicable to western landscapes.  

内陆水环境污染监测的多时相遥感信息模型

介绍了遥感水质监测的基本原理,对遥感技术在水质监测领域的国内外发展现状进行了归纳分析,并论述了建立多时相、通用型内陆水环境污染遥感监测模型的可行性,最后以湘江长沙段为研究区域,创建了适用于DO、CODCr、CODMn、BOD和TN的水污染遥感因子和相应的多时相遥感信息模型。  

Using Multi-Scale Sampling and Spatial Cross-Correlation to Investigate Patterns of Plant Species Richness

Land managers need better techniques to assess exoticplant invasions. We used the cross-correlationstatistic, I _YZ, to test for the presence ofspatial cross-correlation between pair-wisecombinations of soil characteristics, topographicvariables, plant species richness, and cover ofvascular plants in a 754 ha study site in RockyMountain National Park, Colorado, U.S.A. Using 25 largeplots (1000 m²) in five vegetation types, 8 of 12variables showed significant spatial cross-correlationwith at least one other variable, while 6 of 12variables showed significant spatial auto-correlation. Elevation and slope showed significant spatialcross-correlation with all variables except percentcover of native and exotic species. Percent cover ofnative species had significant spatialcross-correlations with soil variables, but not withexotic species. This was probably because of thepatchy distributions of vegetation types in the studyarea. At a finer resolution, using data from ten1 m² subplots within each of the 1000 m² plots, allvariables showed significant spatial auto- andcross-correlation. Large-plot sampling was moreaffected by topographic factors than speciesdistribution patterns, while with finer resolutionsampling, the opposite was true. However, thestatistically and biologically significant spatialcorrelation of native and exotic species could only bedetected with finer resolution sampling. We foundexotic plant species invading areas with high nativeplant richness and cover, and in fertile soils high innitrogen, silt, and clay. Spatial auto- andcross-correlation statistics, along with theintegration of remotely sensed data and geographicinformation systems, are powerful new tools forevaluating the patterns and distribution of native andexotic plant species in relation to landscape structure.  

基于卫星遥感数据的江西德兴铜矿开采环境影响动态监测分析

位于中国南方的江西省德兴矿山开采铜矿已有几十年历史.采矿行为会产生大量废石和尾、,这些废石和尾矿富含铁化合物,不断与氧气、雨水接触,将形成金属离子和酸根离子等污染物,随着降雨过程迅速在地表大面积扩散,最终流入矿山附近的河流、湖泊等水体,因此会造成植被污染、水环境恶化.基于卫星遥感数据源,针对江西德兴铜矿典型的矿山开采环境,对矿山开采环境内植被及水体的影响进行了动态监测分析,可为矿山合理开发、环境监测与可持续发展提供决策分析方法.  

太湖水华的遥感分析

随着太湖流域的经济迅速发展,太湖湖体的富营养化程度日趋严重,特别是在20世纪的后期,水华频繁爆发。国家环保总局常规的水质监测是基于21个点位对全湖进行评价,完成一次采样耗时近1月,其对大面积水华现象的监测具有很大的局限性。文章利用遥感技术快速、大尺度、动态监测的特点,基于多个时相的TM影像对太湖的水温、悬浮物、叶绿素等水质参数的浓度和分布进行了遥感反演,进而对太湖水华的成因、发展程度、影响因素等方面进行分析,从而对太湖水华发生的特点,太湖的水质情况有一个全面的了解。  

Supplementing Land-Use Statistics with Landscape Metrics: Some Methodological Considerations

Landscape monitoring usually relies on land-use statistics whichreflect the share of land-sue/land cover types. In order tounderstand the functioning of landscapes, landscape pattern mustbe considered as well. Indicators which address the spatialconfiguration of landscapes are therefore needed. Thesuitability of landscape metrics, which are computed from thetype, geometry and arrangement of patches, is examined. Two casestudies in a surface mining region show that landscape metricscapture landscape structure but are highly dependent on the datamodel and on the methods of data analysis. For landscape metricsto become part of policy-relevant sets of environmentalindicators, standardised procedures for their computation fromremote sensing images must be developed.