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641.
黄浦江上游底栖动物的指示生物生态研究 总被引:7,自引:1,他引:7
就黄浦江上游水质现状,底栖动物指示种的适用范围及其对污染的指示意义,加以探讨,研究,结果筛选出适应于当前水质状况的底栖动物有颤蚓,水丝蚓,珍珠蚌,钩虾和摇蚊幼虫等指示种,从底栖动物指示种的变化,可预测水质变化的趋势以及季节性的差异。 相似文献
642.
土壤酶活性及其对土壤质量的指示研究进展 总被引:182,自引:3,他引:182
土壤中所进行的生物和生物化学过程是陆地生态系统功能的基础 ,这些过程之所以能够持续进行 ,得益于土壤中酶的作用 .酶是土壤生态系统代谢的一类重要动力 ,土壤中所进行的一切生物学和化学过程都要由酶的催化作用才能完成 .虽然单一种类的土壤酶的催化作用可能是专性的 ,但土壤中酶的来源不同 ,酶的种类繁多 .土壤中已经被鉴定出的约 6 0种酶活性表明 ,土壤酶活性是与土壤质量的很多理化指标相联系的 ,酶的催化作用对土壤中元素 (包括C、N、P、S)循环与迁移有着重要作用 .历史上 ,土壤化学和物理学属性一直被用来作为表征土壤生产力和… 相似文献
643.
Abstract: The 2010 biodiversity target adopted globally and in Europe is an important political commitment for improved biodiversity conservation and management. Whether or not it is achieved will be judged by a set of biodiversity indicators now under development. We reviewed the development of these indicators in Europe and globally, paying particular attention to the need to make the indicators relevant to the purpose; to distinguish between measures of pressure, state, and response; to design and validate the indicators in context; to ensure effective communication with relevant audiences; to turn lists of measures into simple or composite indicators; and to maximize the cost-effectiveness of the indicator process. We conclude that urgent steps are needed to complete the indicator set, reduce and refine the agreed measures, ensure that work is started soon so that reliable reporting occurs in 2010, and start soon on planning for subsequent assessments. 相似文献
644.
645.
Professor S. Openshaw Mike Coombes 《Journal of Environmental Planning and Management》1991,34(1):50-54
Policy indicators applied at a national scale can have considerable financial impact for resource allocations to individual counties, especially if there are extreme local factors. This article develops arid explores a new measure of population dispersal and sparsity and discusses the impact of this indicator in a variety of locations, by using GIS techniques. 相似文献
646.
Harold G. Fowler Maria Inez Pagani Osvaldo Aulino Da Silva Luis Carlos Forti Virgilio Pereira Da Silva Heraldo Luis De Vasconcelos 《Environmental management》1989,13(6):671-675
Leaf-cutting ants of the generaAcromyrmex andAtta are considered the principal polyphagous pests of the Neotropics Although some members of these genera are of economic importance, have a broad geographic distribution, and are extremely good colonizers, others are endemic and closely interact with native ecosystems. Control is generally practiced against any colony, irrespective of its taxonomic status. Indiscriminate control coupled with habitat destruction threatens endemic species with extinction, and, through habitat simplification, favors other pest species. As nests ofAtta are large, having several square meters of nest surface, the endemic taxa can be easily used as environmental indicators for natural ecosystems Likewise, the pest species can be used to detect environmental disturbance As these ants are keystone species and easily identified by nonspecialists, efforts should be made to integrate these into viable conservation programs 相似文献
647.
Karen A. Blocksom Bradley C. Autrey Margaret Passmore Lou Reynolds 《Journal of the American Water Resources Association》2008,44(3):577-593
Abstract: In 2003, we compared two benthic macroinvertebrate sampling methods that are used for rapid biological assessment of wadeable streams. A single habitat method using kick sampling in riffles and runs was compared to a multiple habitat method that sampled all available habitats in proportion of occurrence. Both methods were performed side‐by‐side at 41 sites in lower gradient streams of the Piedmont and Northern Piedmont ecoregions of the United States, where riffle habitat is less abundant. Differences in sampling methods were examined using similarity indices, two multimetric indices [the family‐level Virginia Stream Condition Index (VSCI) and the species‐level Macroinvertebrate Biotic Integrity Index (MBII)], their component metrics, and bioassessment endpoints based on each index. Index scores were highly correlated between single and multiple habitat field methods, and sampling method comparability, based on comparison of similarities between and within sampling methods, was particularly high for species level data. The VSCI scores and values of most of its component metrics were not significantly higher for one particular method, but relationships between single and multiple habitat values were highly variable for percent Ephemeroptera, percent chironomids, and percent Plecoptera and Trichoptera (Hydropsychidae excluded). A similar level of variability in the relationship was observed for the MBII and most of its metrics, but Ephemeroptera richness, percent individuals in the dominant five taxa, and Hilsenhoff Biotic Index scores all exhibited differences in values between single and multiple habitat field methods. When applied to multiple habitat samples, the MBII exhibited greater precision, higher index scores, and higher assessment categories than when applied to single habitat samples at the same sites. In streams with limited or no riffle habitats, the multiple habitat method should provide an adequate sample for biological assessment, and at sites with abundant riffle habitat, little difference would be expected between the single and multiple habitat field methods. Thus, in geographic areas with a wide variety of stream types, the multiple habitat method may be more desirable. Even so, the variability in the relationship between single and multiple habitat methods indicates that the data are not interchangeable, and we suggest that any change in sampling method should be accompanied by a recalibration of any existing assessment tool (e.g., multimetric index) with data collected using the new method, regardless of taxonomic level. 相似文献
648.
Assessing coastal vulnerability to climate change: comparing segmentation at global and regional scales 总被引:2,自引:0,他引:2
Silvia Torresan Andrea Critto Matteo Dalla Valle Nick Harvey Antonio Marcomini 《Sustainability Science》2008,3(1):45-65
Recent concerns about potential climate-change effects on coastal systems require the application of vulnerability assessment
tools in order to define suitable adaptation strategies and improve coastal zone management effectiveness. In fact, while
various research efforts were devoted to evaluate coastal vulnerability to climate change on a national to global level, fewer
applications were carried out so far to develop more comprehensive and site-specific vulnerability assessments suitable to
plan possible adaptation measures at the regional scale. In this respect, specific indicators are needed to address climate-change-related
issues for coastal zones and to identify vulnerable areas at the regional level. Two sets of coastal vulnerability indicators
were selected, one for regional and one for global studies, respectively, concerning the same features of coastal systems,
including topography and slope, geomorphological characteristics, presence and distribution of wetlands and vegetation cover,
density of coastal population and number of coastal inhabitants. The proposed set of indicators for the regional scale was
chosen taking into account the availability of environmental and territorial data for the whole coastal area of the Veneto
region and was based on site-specific datasets characterized by a spatial resolution appropriate for a regional analysis.
Moreover, a GIS-based segmentation procedure was applied to divide the coastline into linear segments, homogeneous in terms
of vulnerability to climate change and sea-level rise at the regional scale. This approach allowed to divide the Veneto shoreline
into 140 segments with an average length of about 1 km, while the global scale approach identified four coastal segments with
an average length of about 66 km. The performed comparison indicated how the more detailed approach adopted at the regional
scale is essential to understand and manage the complexities of the specific study area. In fact, the 25-m DEM employed at
the regional scale provided a more accurate differentiation of the coastal area's elevation and thus of coastal susceptibility
to the inundation risks, compared to the 1-km DEM used at the global level. Moreover, at the regional level the use of a 1:20,000
geomorphological map allowed to differentiate the unique landform class detected at the global level (e.g., fluvial plain)
in a variety of more detailed coastal typologies (e.g., open coast eroding sandy shores backed by bedrock) characterized by
a different sensitivity to climate change and sea-level rise. Accordingly, the information provided by regional indicators
can support decision-makers in improving the management of coastal resources by considering the potential impacts of climate
change and in the definition of appropriate actions to reduce inundation risks, to avoid the potential loss of valuable wetlands
and vegetation and to plan the nourishment of sandy beaches subject to erosion processes. 相似文献
649.
化工过程本质安全性之模糊评价系统 总被引:2,自引:1,他引:1
在综合分析化工过程构成的基础上,建立的化工过程本质安全性评价指标,借鉴国内外本质安全评价的研究,应用Matlab模糊推理系统,以评价指标的等级划分、隶属度函数设计及推理规则设定等为主线,建立化工过程本质安全性模糊评价系统,实现评价指标和评价推理结果的可视化。通过甲苯高温加氢脱烷烃制取苯的工艺过程,实施不同工艺路线及其操作条件改变的本质安全性评价,验证了所建立模糊评价系统的可行性。研究结果对指导化工安全设计和安全评价、减少和消除重大危险源,进一步提升我国化工行业的整体安全水平具有重要的理论和现实意义。 相似文献
650.