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1.
The methodology for developing and mapping a hierarchical Ecological Land Classification (ELC) is presented. The classification provided a systematic methodology that explained the distribution and composition of southern New Brunswick's forested landscape. The nested structure of the ELC identified and provided a hierarchical linkage between ecosystems from the size of forest stands to climate regions. This framework made the collection and analysis of data efficient and gave confidence that tree species distributions, which were central to understanding the influence of abiotic factors on the forest systems, were controlled by the factors examined at each level of the hierarchy. This ELC methodology, developed for the Fundy Model forest, was successful in describing and mapping the Climate, Geomorphologic, and Regolith controlled forest ecosystems. Preliminary classification indicates that spatial referencing of the Site Level is achievable.  相似文献   

2.
This study attempts to determine the scale-dependent hierarchical spatial variation and longitudinal distributions of Sicyopterus japonicus year round. The distribution of S. japonicus in the Datuan Stream in northern Taiwan was surveyed during the fall and winter 2007, as well as the spring and summer of 2008. The spatial structure of S. japonicus density was modeled using geostatistics. The longitudinal distributions of S. japonicus density were then estimated using kriging and hydrology distance with nested variogram models. Variography results indicate that nested variogram models could reflect the hierarchical structure in the spatial variation of seasonal S. japonicus density, with the small, median, and large ranges representing three nested scales. Models for the four seasons were consistent in that they shared the same shape of variogram models with various ranges and sill values. This model shape consistency implies stationary spatial correlations in the longitudinal fish distribution across the four seasons. The Kriging geostatistical method based on the multiple scales nested variogram models also provided robust estimates of S. japonicus densities at unsampled sections. We conclude that S. japonicus densities exhibit hierarchical patterns and variation in the four seasons along the study stream. Geostatistical methods with a nested variograms and hydrological distance are a highly effective means of delineating the hierarchical structure in longitudinal patterns of S. japonicus density in each season, providing estimates of the S. japonicus density for hierarchically structured spatial distributions and expanding knowledge of S. japonicus beyond the limits imposed by spatial and temporal scales.  相似文献   

3.
Energy-extraction results in significant disturbance to rangelands in Wyoming and other western US states. Although reclamation is required by law, US General Accounting Office reports from 1999 and 2005 are clear that affected government agencies have--over much of the past decade--had difficulty accomplishing mandated environmental monitoring of extraction-related disturbance. We evaluated two pipeline rights of way (ROW) using nested images (1- or 2- with 13- or 20-mm ground sample distance (GSD)) acquired during Very-Large Scale Aerial (VLSA) surveys. Aerial monitoring allowed for the collection of large numbers of geocoded samples, and for subsequent cover measurements using methods with demonstrated accuracy equal to that of conventional ground-based methods. Both pipelines had vegetative-cover deficiencies relative to their Plan of Development (POD) requirements. Using bare ground and ground-cover measurements from the higher-resolution imagery, we present a spatial representation of each pipeline ROW that allows quick identification of sections of the ROW that may need further reclamation action to meet POD standards. We also present aerial monitoring costs. We recommend VLSA pipeline surveys as a means for facilitating required environmental monitoring and for addressing the monitoring backlog that has developed with increased energy-extraction activity.  相似文献   

4.
美国EPA地表水质监测与评估的点位设计介绍   总被引:1,自引:0,他引:1  
介绍了美国EPA地表水质监测与评估的点位设计。首先,指导性文件《基本水质监测方案》中的环境监测计划要求建立1个不少于1 000个点位的国家地表水质环境监测网,并提出了点位设计的标准,包括4点基本要求和针对每一类水域的具体要求。其次,另一指导性文件《准备州综合水质评估(305b报告)和电子升级:报告内容的准则》提出了1种新的对水质的综合性评估技术,要求在传统的判断点位设计的基础上增加概率统计点位设计方法。最后,全国一致的概率统计点位设计是相当有效的获知全国范围的水质情况及变化趋势的方法,EPA完全支持通过这种概率统计点位设计的方法来评估更多的水质状况。概率统计点位设计是EPA地表水质监测与评估的点位设计的发展趋势。  相似文献   

5.
Previous studies have combined random-site hierarchical sampling designs with analysis of variance techniques, and grid sampling with spatial autocorrelation analysis. We illustrate that analysis techniques and sampling designs are interchangeable using densities of an infaunal bivalve from a study in Poverty Bay, New Zealand. Hierarchical designs allow the estimation of variances associated with each level, but high-level factors are imprecisely estimated, and they are inefficient for describing spatial pattern. Grid designs are efficient for describing spatial pattern, and are amenable to conventional analysis. Our example deals with a continuous spatial habitat, but our conclusions also apply in disjunct or patchy habitats. The influence of errors in positioning is also assessed. The advantages of systematic sampling are reviewed, and more efficient hierarchical approaches are identified. The distinction between biological and statisticalsignificance in all analyses is emphasised.  相似文献   

6.
The temporal variation in the concentrations of particulate trace metals (Cu, Pb and Zn) and total suspended solids (TSS) was examined in three rivers that drain into the Port Jackson estuary, Australia, using a nested, hierarchical sampling design. Sampling was conducted between March and June 1999, under low flow conditions. The sampling design incorporated four temporal scales (hours, days, weeks and months). It was considered that hours, days, weeks and months were representative of such time scales and could be analyzed as random, nested sources of variation in an analysis of variance (ANOVA). Significant variation was found at temporal scales ranging from hours, within the same day, to months. The amount and scales of variation differed between particulate trace metals and TSS concentrations and between rivers. In many cases, differences between small-scale were as important as differences between months. The results suggest that higher anthropogenic influences cause higher variability at small temporal scale. Results indicate the need for nested sampling designs to be incorporated into studies of temporal variation in order to unconfound small-scale temporal variation. The conclusions of this study are likely to be applicable to other water quality variables and pollutants.  相似文献   

7.
Monitoring drinking water quality is an important public health issue. Two objectives from the 4 years, six nations, EU Project μAqua were to develop hierarchically specific probes to detect and quantify pathogens in drinking water using a PCR-free microarray platform and to design a standardised water sampling program from different sources in Europe to obtain sufficient material for downstream analysis. Our phylochip contains barcodes (probes) that specifically identify freshwater pathogens that are human health risks in a taxonomic hierarchical fashion such that if species is present, the entire taxonomic hierarchy (genus, family, order, phylum, kingdom) leading to it must also be present, which avoids false positives. Molecular tools are more rapid, accurate and reliable than traditional methods, which means faster mitigation strategies with less harm to humans and the community. We present microarray results for the presence of freshwater pathogens from a Turkish lake used drinking water and inferred cyanobacterial cell equivalents from samples concentrated from 40 into 1 L in 45 min using hollow fibre filters. In two companion studies from the same samples, cyanobacterial toxins were analysed using chemical methods and those dates with highest toxin values also had highest cell equivalents as inferred from this microarray study.  相似文献   

8.
Control of workplace exposure to beryllium is a growing issue in the United States and other nations. As the health risks associated with low-level exposure to beryllium are better understood, the need increases for improved analytical techniques both in the laboratory and in the field. These techniques also require a greater degree of standardization to permit reliable comparison of data obtained from different locations and at different times. Analysis of low-level beryllium samples, in the form of air filters or surface wipes, is frequently required for workplace monitoring or to provide data to support decision-making on implementation of exposure controls. In the United States and the United Kingdom, the current permissible exposure level is 2 microg m(-3) (air) and the United States Department of Energy has implemented an action level of 0.2 microg m(-3) (air) and 0.2 microg/100 cm(2) (surface). These low-level samples present a number of analytical challenges, including (1) a lack of suitable standard reference materials, (2) unknown robustness of sample preparation techniques, (3) interferences during analysis, (4) sensitivity (sufficiently low detection limits), (5) specificity (beryllium speciation) and (6) data comparability among laboratories. Additionally, there is a need for portable, real-time (or near real-time) equipment for beryllium air monitoring and surface wipe analysis that is both laboratory-validated and field-validated in a manner that would be accepted by national and/or international standards organizations. This paper provides a review of the current analytical requirements for trace-level beryllium analysis for worker protection and also addresses issues that may change those requirements. The current analytical state of the art and relevant challenges facing the analytical community will be presented, followed by suggested criteria for real-time monitoring equipment. Recognizing and addressing these challenges will present opportunities for laboratories, research and development organizations, instrument manufacturers and others.  相似文献   

9.
基于GIS的珠三角区域空气质量实况发布平台介绍   总被引:2,自引:1,他引:1  
地理信息系统是在计算机软件和硬件支持下,对整个或者部分地球表层空间中的各类地理信息数据进行采集、存储、管理、运算、分析、显示和描述的技术系统。根据中国发布的环境空气质量新标准,提出了基于地理信息系统的区域空气质量实况发布平台的总体设计思路,介绍了这一平台的开发与运行环境、主要功能模块设计和实现方法。该平台已成功应用于珠江三角洲区域。通过广东省环境保护公众网信息平台,实时更新各个站点最新的空气监测数据,为广东开展环境整治工作以及居民日常出行提供参考。  相似文献   

10.
Thermal imaging is a nondestructive testing method for monitoring internal material changes that are indicated by changes in an object’s surface temperature. In this study, field observation using thermographs was applied to monitor and analyze the breach process of large-scale earth dams. The earth dam test site was Landao Creek in Nantou County, Taiwan. Four field tests were performed to monitor and analyze a single earth dam and two successive earth dams. Ponding first occurred at the lowland of the riverbed upstream, and base seepage occurred at the base of the dam downstream; overtopping failure soon followed. Earth-dam failure mode is affected by the topographic characteristics of the riverbed; specifically, lowland areas are prone to ponding upstream, which causes piping and seepage downstream as well as subsequent breaches. Ponding and piping cause water seepage and soil wetting, which are reflected in lower surface temperatures recorded on thermographs. Thermographs can monitor changes in surface temperature to evaluate the potential failure modes of dams. Dam surfaces with large temperature variations may be potential failure areas. If confirmed, this fact may prove useful for failure-mode prediction. This paper proposes a monitoring index to reflect the temperature changes in a given period, and this study verified it empirically.  相似文献   

11.
Nowadays, usage of compensatory models in land evaluation process and site selection is broadly observed. Meanwhile, methods such as analytical hierarchy process are used more than the others. Whether the usage of compensatory model methods in site selection studies is essentially correct or not is an issue that should be hesitated. In this model, inefficiency of a factor, to be offset by strength of others, means that in urban development site selection, if somewhere has unsuitable aspect but suitable slope, the aspect deficiency will be compensated by the slope. But quodlibet reflection is that in this model, sometimes, deficiency of proximity to fault can be compensated by other parameters strength. And finally, a place is diagnosed as a suitable area for urban development that is close to the fault. This research aims at examination of compensatory models application in urban development site selection of Taleghan Basin using analytical hierarchy process as one of the compensatory model methods. Among this the weaknesses and strengths of compensatory model were analyzed carefully. Results indicate that despite usefulness of this model in being fast, easy, and low expense, it has some weaknesses like very high sensitivity to decision maker’s idea.  相似文献   

12.
地下水采样方法比对研究   总被引:1,自引:0,他引:1  
选取3种地下水采样方法开展方法比对研究。通过系统分析监测数据,指出了3种方法所采水样在基本水质参数、无机离子、金属、挥发性有机物以及感官类指标等项目监测上的显著差异,指出了各种方法的适用性并分析原因。结果表明:与贝勒管法、潜水泵法相比,低流速法有效地解决了采样操作过程中易产生的曝气问题;对井内水体扰动较小,降低了水样浊度;减小了井内水位的大幅度泄降,避免了不同层位间污染物的迁移及周边水和井内滞水的交叉污染;节约了场地操作时间和后期污水处理所需花费。因此,低流速法在采取代表性水质样品方面更具方法优势。  相似文献   

13.
Montgomery County, Maryland faces a growing problem that confronts local governments across the country: the cumulative impacts that population growth and the resulting land-use changes are having on local streams and their accompanying ecosystems. County officials found they needed an affordable tool to serve as a report card for stream health, and began a biomonitoring program in 1994. By 1997 county officials had monitored all 23 watersheds within the county's boundaries, and in 1998 the county published its first Countywide Stream Protection Strategy (CSPS). The County uses the CSPS to prioritize its watershed restoration efforts to those areas most in need of immediate remediation. Six primary programs now support or require the use of information from Montgomery County's biomonitoring program. And, the lessons learned from Montgomery County can help other county and local governments develop similar programs of their own.  相似文献   

14.
The sensitivity of soil landscapes to climatic variability andhydroclimatic events can be expressed as a landscape change safety factor, the ratio of potential disturbance to resistance to change. The use of a geographic information system (GIS) enables the spatially-explicit modeling of landscape sensitivity, but also raises the risk of violating the characteristic scales of disturbance and resistance, because the GIS technically simplifies the extrapolation of models, and associated concepts, to landscapes and scales notrepresented by the digital data base. Embedding landscape sensitivity into hierarchy theory, the formal analysis of the hierarchical structure of complex systems, provides a conceptual framework for the transfer of models and variablesamong landscape scales. In the subhumid southern Canadian plains, major hydroclimatic events (strong winds, intense rain,rapid snow melt) cause much of the physical disturbance of soillandscapes and terrestrial ecosystems. Prolonged dry or wet weather influences the resistance of soil and vegetation to these events. The potential disturbance of soil landscapes therefore can be derived from the probabilities of extreme events and seasonal conditions, as recorded in instrumental and proxy climate records. This time series analysis can belinked to the modeling of landscape sensitivity by establishingthe probabilities of hydroclimatic events and climatic conditions which may exceed or lower the resistance of individual soil landscapes.  相似文献   

15.
半透膜采样技术是一种可原位、连续、动态监测水环境中非极性、弱极性有机污染物的被动采样技术,已在国内外发展20余年,但在环境监测中使用很少。从半透膜被动采样特点、采样器构造入手,着重对应用该技术的环节进行剖析,同时涉及被动采样结果及其评价方法。最后以多环芳烃(PAHs)为例,综述了近年来SPMD技术监控水体中非极性、弱极性有机污染物的常用分析技术及其发展。  相似文献   

16.
Impact significance determination practice tends to be highly variable. Too often insufficient consideration is given to good practice insights. Also, impact significance determinations are frequently narrowly defined addressing, for example, only individual, negative impacts, focusing on bio-physical impacts, and not seeking to integrate either the Precautionary Principle or sustainability.This article seeks to extend the boundaries of impact significance determination practice by providing an overview of good general impact significance practices, together with stakeholder roles and potential methods for addressing significance determination challenges. Relevant thresholds, criteria, contextual considerations and support methods are also highlighted. The analysis is then extended to address how impact significance determination practices change for positive as compared with negative impacts, for cumulative as compared with individual impacts, for socio-economic as compared with bio-physical impacts, when the Precautionary Principle is integrated into the process, and when sustainability contributions drive the EIA process and related impact significance determinations. These refinements can assist EIA practitioners in ensuring that the scope and nature of impact significance determinations reflect the broadened scope of emerging EIA requirements and practices. Suggestions are included for further refining and testing of the proposed changes to impact significance determination practice.  相似文献   

17.
Many recent developments in coastal science have gone against the demands of European Union legislation. Coastal dune systems which cover small areas of the earth can host a high level of biodiversity. However, human pressure on coastal zones around the world has increased dramatically in the last 50 years. In addition to direct habitat loss, the rapid extinction of many species that are unique to these systems can be attributed to landscape deterioration through the lack of appropriate management. In this paper, we propose to use of an ecosystem classification technique that integrates potential natural vegetation distribution as a reference framework for coastal dune EU Habitats (92/43) distribution analysis and assessment. As an example, the present study analyses the EU Habitats distribution within a hierarchical ecosystem classification of the coastal dune systems of central Italy. In total, 24 land elements belonging to 8 land units, 5 land facets, 2 land systems and 2 land regions were identified for the coastal dunes of central Italy, based on diagnostic land attributes. In central Italy, coastal dune environments including all the beach area, mobile dunes and all the fixed-dune land elements contain or could potentially hold at least one EU habitat of interest. Almost all dune slack transitions present the potentiality for the spontaneous development of EU woodlands of interest. The precise information concerning these ecosystems distribution and ecological relationships that this method produces, makes it very effective in Natura 2000 European network assessment. This hierarchical ecosystem classification method facilitates the identification of areas to be surveyed and eventually bound, under the implementation of EU Habitat directive (92/43) including areas with highly disturbed coastal dune ecosystems.  相似文献   

18.
Bioassessment of nonwadeable streams in the United States is increasing, but methods for these systems are not as well-developed as for wadeable streams. In this study, we compared six macroinvertebrate field sampling methods for nonwadeable streams adapted from those used by three major programs: the U.S. Environmental Protection Agencys Environmental Monitoring and Assessment Program-Surface Waters, the U.S. Geological Surveys National Water Quality Assessment Program, and the Ohio Environmental Protection Agency, Division of Surface Water Biocriteria Program. We performed all six methods at 60 sites across four rivers and measured water chemistry and physical habitat at each site to assess abiotic conditon. Sites were divided into two groups: those influenced by navigational lock and dam structures (restricted flow, or RF) and those free-flowing or with lowhead dams (run-of-the-river, or ROR). Metrics based on passive Hester-Dendy artificial substrate samplers differed greatly from active sampling methods (i.e., using nets) but represented abiotic conditions well in both ROR and RF sites. Although metric values were similar across certain sampling methods, the metrics significantly correlated with abiotic variables varied among methods and between ROR and RF sites. These results emphasize that methods are not interchangeable, and the ability to detect certain stressors depends on sampling method.The U.S. Governments right to retain a non-exclusive, royalty free licence in and to any copyright is acknowledged.  相似文献   

19.
Point Sampling Digital Imagery with ‘Samplepoint’   总被引:1,自引:0,他引:1  
Measuring percent occurrence of objects from digital images can save time and expense relative to conventional field measurements. However, the accuracy of image analysis had, until now, not reached the level of the best conventional field measurements. Additionally, most image-analysis software programs require advanced user training to successfully analyze images. Here we present a new software program, ‘SamplePoint,’ that provides the user a single-pixel sample point and the ability to view and identify the pixel context. We found SamplePoint to allow accuracy comparable with the most accurate field-methods for ground-cover measurements. Expert use of the program requires minimal training and its ease of use allows rapid measurements from image data. We recommend SamplePoint for calibrating the threshold-detection level of image-analysis software or for making direct measurements of percent occurrence from digital images.  相似文献   

20.
建立了偏振能量色散X射线荧光光谱法测定土壤和沉积物中稀土元素的方法,该方法较传统的方法具有前处理简单、测量自动化程度高、灵敏度高和检出限低(检出限范围为0.05~2.80 mg/kg)等优点。对土壤和沉积物标准物质的测定结果表明:测定结果与认定值能较好吻合,相对标准偏差范围为0.2%~9.4%,能满足测试的需求。分别用该方法和电感耦合等离子体质谱法对实际样品进行测定,2种方法的测定结果有较好的一致性,表明该方法测定结果准确可靠,可用于实际样品的测定。  相似文献   

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