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1.
Spartina pectinata (prairie cordgrass) was grown under five hydroperiods (wet–dry cycles) to determine its potential for use in stormwater wetlands, particularly as an alternative to the highly invasive Phalaris arundinacea (an exotic grass). Rhizomes planted in outdoor microcosms grew vigorously in all treatments, namely, weekly flooding in early summer, weekly flooding in late summer, flooding every three weeks throughout the summer, weekly flooding throughout the summer, and no flooding. Neither the timing nor frequency of 24-hour floods (10–20 cm deep) affected total stem length (grand mean 1003 ± 188.8 cm per pot, n = 140) or above-ground biomass (46.5 ± 8.3 g per pot, equivalent to ∼360 g/m2). However, by late summer, fewer new tillers were found in unflooded microcosms, indicating that vegetative expansion is drought-sensitive. The growth of Spartina plants was further assessed with and without Glyceria striata (a native grass) and Phalaris arundinacea. Glyceria growth was not affected by hydrologic treatment. Glyceria reduced Spartina growth by approximately 11%, suggesting potential as a cover crop that might reduce establishment and growth of Phalaris seedlings. Seeds of Phalaris did not germinate, but branch fragments established where soil was moist from flooding, regardless of the presence of Glyceria. The ability of Spartina to establish vegetatively and grow well under variable water levels leads us to recommend further testing in stormwater wetlands, along with early planting of Glyceria to reduce weed invasions.  相似文献   

2.
Abstract: Conservation practices are regularly implemented within agricultural watersheds throughout the United States without evaluating their ecological impacts. Impact assessments documenting how habitat and aquatic biota within streams respond to these practices are needed for evaluating the effects of conservation practices. Numerous sampling protocols have been developed for monitoring streams. However, protocols designed for monitoring studies are not appropriate for impact assessments. We developed guiding principles for designing impact assessments of ecological responses to conservation practices. The guiding principles are as follows: (1) develop the hypothesis first, (2) use replicated experimental designs having controls and treatments, (3) assess the habitat and biological characteristics with quantitative and repeatable sampling methods, (4) use multiple sampling techniques for collecting aquatic organisms, and (5) standardize sampling efforts for aquatic organisms. The guiding principles were applied in designing a study intended to evaluate the influence of herbaceous riparian buffers on channelized headwater streams in central Ohio. Our example highlights that the application of our recommendations will result in impact assessments that are hypothesis‐driven and incorporate quantitative methods for the measurement of abiotic and biotic attributes.  相似文献   

3.
成都市外来入侵物种调查研究   总被引:3,自引:0,他引:3  
对成都市外来入侵物种的种类、数量、分布和危害进行了调查,初步发现有蔗扁蛾(香蕉蛾)Opogona sacchari(Bojer)、大瓶螺(福寿螺、苹果螺、雪螺)Pomacea canaliculata Spix、空心莲子草(水花生、喜旱莲子草)Altertian-thera philoxeroides(Mart.)Griseb、凤眼莲(水葫芦、凤眼蓝)Eichhornia crassipes (Mart.)Solms、牛蛙Rana cntesbei-ana Shaw等.提出了引入扩散原因及危害分析、防除方法,近期可能入侵成都市的外来物种,防治外来入侵物种工作存在的问题.  相似文献   

4.
采用近年常用于重金属污染的地积累指数法及生态危害指数评价法对关中西部某铅锌冶炼区表层土壤中重金属污染情况进行了评价.结果表明,两种方法均能对人为污染行为作出较为科学的评价,且两种方法可得到相似的评价结果:该冶炼区周边土壤Cd元素为中重度污染,Pb为中等污染,Zn和Cu为轻微污染.生态危害指数评价法和地积累指数评价法两种方法都是基于沉积学理论提出,两者各有侧重点,对于重金属污染的系统评价各具合理性;但在对土壤重金属污染进行评价时,有一定的局限性,建议在修正其参数后综合应用.  相似文献   

5.
在高锰酸盐指数的测定中,干扰最为严重且难以消除的是氯离子(Cl-)的影响。高浓度氯离子的干扰会导致测定结果偏差大,无法界定高锰酸盐指数是否达标。对高含氯水样高锰酸盐指数测定新方法(改进的高锰酸盐指数法)的实验研究结果表明,在采用标准高锰酸钾法对高含氯水样进行的高锰酸盐指数测定中,利用稀释方法,在碱性条件下用硫酸锰作催化剂,可以避免氯离子的干扰,提高了高锰酸钾对有机物的氧化率,能真实地反映水样中有机物的污染程度。  相似文献   

6.
新疆外来入侵种现状研究   总被引:1,自引:0,他引:1  
通过对我国新疆9种已呈现出较大危害的外来入侵种的分布范围、生境类型、种群建立状况、起源、首次发现或引入的地点及时间、来源、引入路径、入侵途径、经济和生态影响等内容进行了研究,并深入分析了目前外来入侵种管理等方面存在的问题,提出了外来入侵物种预防、控制和管理措施。  相似文献   

7.
A Proposed Aquatic Plant Community Biotic Index for Wisconsin Lakes   总被引:2,自引:0,他引:2  
The Aquatic Macrophyte Community Index (AMCI) is a multipurpose tool developed to assess the biological quality of aquatic plant communities in lakes. It can be used to specifically analyze aquatic plant communities or as part of a multimetric system to assess overall lake quality for regulatory, planning, management, educational, or research purposes. The components of the index are maximum depth of plant growth; percentage of the littoral zone vegetated; Simpson's diversity index; the relative frequencies of submersed, sensitive, and exotic species; and taxa number. Each parameter was scaled based on data distributions from a statewide database, and scaled values were totaled for the AMCI value. AMCI values were grouped and tested by ecoregion and lake type (natural lakes and impoundments) to define quality on a regional basis. This analysis suggested that aquatic plant communities are divided into four groups: (1) Northern Lakes and Forests lakes and impoundments, (2) North-Central Hardwood Forests lakes and impoundments, (3) Southeastern Wisconsin Till Plains lakes, and (4) Southeastern Wisconsin Till Plains impoundments, Driftless Area Lakes, and Mississippi River Backwater lakes. AMCI values decline from group 1 to group 4 and reflect general water quality and human use trends in Wisconsin. The upper quartile of AMCI values in any region are the highest quality or benchmark plant communities. The interquartile range consists of normally impacted communities for the region and the lower quartile contains severely impacted or degraded plant communities. When AMCI values were applied to case studies, the values reflected known impacts to the lakes. However, quality criteria cannot be used uncritically, especially in lakes that initially have low nutrient levels.  相似文献   

8.
黄峥嵘 《四川环境》1992,11(1):34-39
我省自八十年代初始,已开展了生态农业试点建设,在不同区域条件下取得了明显的经济、生态、社会三大效益。“八五”期间试点范围还将会扩大,在此基础上,提出评价指标为生态农业建设规范化提供依据。本文拟写评价指标体系及其标准原则、评价方法、指标体系的解释和评价单项指标群体。通过指标评价方法,既可找出影响生态经济功能的限制因子,又可找到问题的突破口及配套措施。将有效地促进县级生态农业的健康发展。  相似文献   

9.
外来物种入侵是威胁国家生物多样性、生态安全和公众健康的重大安全问题。《生物安全法》的通过为防治外来物种入侵提供了综合性的制度规范。我国防治外来物种入侵法治实践长期以行政规制为主导,较少关注司法机关、企事业单位、社会组织和公众等法律主体在治理中的作用。行政规制治理中执法机构及其职能与管理手段的碎片化,亦无法回应高风险社会防治外来物种入侵的需要。我国防治外来物种入侵法治建设应当坚持整体性治理理念,以整体安全观为指导,坚持风险预防、防治结合,明确综合管理程序及责任法律制度和一体化协同执法机制,健全防治外来物种入侵行政规制体系;引入公众参与,形成政府、企事业单位、社会组织和公众协同治理外来物种入侵,鼓励外来物种入侵公益诉讼等,完善防治外来物种入侵的多元共治体系,共促国家生物安全治理体系。  相似文献   

10.
A Vegetation-Based Method for Ecological Diagnosis of Riverine Wetlands   总被引:2,自引:0,他引:2  
/ The management of riverine wetlands, recognized as a major component of biodiversity in fluvial hydrosystems, is problematic. Preservation or restoration of such ecosystems requires a method to assess the major ecological processes operating in the wetlands, the sustainability of the aquatic stage, and the restoration potential of each riverine wetland. We propose a method of diagnosis based on aquatic macrophytes and helophytes. Plant communities are used because they are easy to survey and provide information about (1) the origin of a water supply (i.e., groundwater, seepage, or surface river water) and its nutrient content, (2) effects of flood disturbances, and (3) terrestrialization processes. The novelty of the method is that, in contrast to available typologies, it is based on the interference of gradients resulting from several processes, which makes it possible to predict wetland sustainability and restoration potential. These predictions result from knowledge of the processes involved in terrestrialization, i.e., the influence of flood disturbances, occurrence of groundwater supplies, trophic degree, and water permanency of the habitat during a yearly cycle. The method is demonstrated on five different river systems.  相似文献   

11.
采用地积累指数法和潜在生态风险指数法对广西某蔗田土壤中重金属污染进行评价。结果表明:4种重金属元素的地积累指数污染程度由强到弱依次为:Cd〉Zn〉Pb〉Cu,潜在生态危害指数污染程度由强到弱依次为:Cd〉Pb〉Cu〉Zn,其中zn的影响程度发生了变化。2种评价方法的结果存在差异,蔗田土壤的地积累指数污染程度处于无污染情况,而潜在生态危害指数污染程度处于低度危害程度。潜在生态危害指数考虑外源重金属的富集程度和不同重金属的生物毒性的影响,使其评价结果更准确。  相似文献   

12.
Increasingly government agencies are seeking to quantify the outcomes of proposed policy options in terms of ecosystem service benefits, yet conflicting definitions and ad hoc approaches to measuring ecosystem services have created confusion regarding how to rigorously link ecological change to changes in human well-being. Here, we describe a step-by-step framework for producing ecological models and metrics that can effectively serve an economic-benefits assessment of a proposed change in policy or management. A focus of the framework is developing comparable units of ecosystem goods and services to support decision-making, even if outcomes cannot be monetized. Because the challenges to translating ecological changes to outcomes appropriate for economic analyses are many, we discuss examples that demonstrate practical methods and approaches to overcoming data limitations. The numerous difficult decisions that government agencies must make to fairly use and allocate natural resources provides ample opportunity for interdisciplinary teams of natural and social scientists to improve methods for quantifying changes in ecosystem services and their effects on human well-being. This framework is offered with the intent of promoting the success of such teams as they support managers in evaluating the equivalency of ecosystem service offsets and trades, establishing restoration and preservation priorities, and more generally, in developing environmental policy that effectively balances multiple perspectives.  相似文献   

13.
随着世界经济贸易的发展,外来物种入侵成为威胁生物多样性、公众健康,甚至生态安全和国家安全的重大问题。我国目前在外来物种入侵相关立法方面存在立法理念滞后、调整范围欠充分、监管碎片化、法律制度缺失且责任追究机制单一等问题,无法有效回应高风险社会对外来物种入侵的防范。在国内外相关制度经验总结的基础上,我国防治外来物种入侵的相关法律法规应在《生物安全法》的指导下,确立整体生态安全理念,采取风险预防原则,健全外来物种风险评估、引种许可证、全过程跟踪监测、公众参与和法律责任制度,优化外来物种风险管理机制,促进生物安全治理体系进一步完善。  相似文献   

14.
To assist risk assessors at the Department of Energy’s Savannah River Site (SRS), a Geographic Information System (GIS) application was developed to provide relevant information about specific receptor species of resident wildlife that can be used for ecological risk assessment. Information was obtained from an extensive literature review of publications and reports on vertebrate- and contaminant-related research since 1954 and linked to a GIS. Although this GIS is a useful tool for risk assessors because the data quality is high, it does not describe the species’ site-wide spatial distribution or life history, which may be crucial when developing a risk assessment. Specific receptor species on the SRS were modeled to provide an estimate of an overall distribution (probability of being in an area). Each model is a stand-alone tool consisting of algorithms independent of the GIS data layers to which it is applied and therefore is dynamic and will respond to changes such as habitat disturbances and natural succession. This paper describes this modeling process and demonstrates how these resource selection models can then be used to produce spatially explicit exposure estimates. This approach is a template for other large federal facilities to establish a framework for site-specific risk assessments that use wildlife species as endpoints.Current address: Biology Department, University of South Dakota, Vermillion, SD 57069  相似文献   

15.
A water quality index expressed as a single number is developed to describe overall water quality conditions using multiple water quality variables. The index consists of water quality variables: dissolved oxygen, specific conductivity, turbidity, total phosphorus, and fecal coliform. The objectives of this study were to describe the preexisting indices and to define a new water quality index that has advantages over these indices. The new index was applied to the Big Lost River Watershed in Idaho, and the results gave a quantitative picture for the water quality situation. If the new water quality index for the impaired water is less than a certain number, remediation—likely in the form of total maximum daily loads or changing the management practices—may be needed. The index can be used to assess water quality for general beneficial uses. Nevertheless, the index cannot be used in making regulatory decisions, indicate water quality for specific beneficial uses, or indicate contamination from trace metals, organic contaminants, and toxic substances.  相似文献   

16.
Europe is severely affected by alien invasions, which impact biodiversity, ecosystem services, economy, and human health. A large number of national, regional, and global online databases provide information on the distribution, pathways of introduction, and impacts of alien species. The sufficiency and efficiency of the current online information systems to assist the European policy on alien species was investigated by a comparative analysis of occurrence data across 43 online databases. Large differences among databases were found which are partially explained by variations in their taxonomical, environmental, and geographical scopes but also by the variable efforts for continuous updates and by inconsistencies on the definition of “alien” or “invasive” species. No single database covered all European environments, countries, and taxonomic groups. In many European countries national databases do not exist, which greatly affects the quality of reported information. To be operational and useful to scientists, managers, and policy makers, online information systems need to be regularly updated through continuous monitoring on a country or regional level. We propose the creation of a network of online interoperable web services through which information in distributed resources can be accessed, aggregated and then used for reporting and further analysis at different geographical and political scales, as an efficient approach to increase the accessibility of information. Harmonization, standardization, conformity on international standards for nomenclature, and agreement on common definitions of alien and invasive species are among the necessary prerequisites.  相似文献   

17.
Several submerged barges were recently removed from the Passaic River, New Jersey, USA, in two areas (areas 1 and 2) where contaminated sediments are known to exist. During removal of the single barge in area 1, elevated turbidity levels and chemical parameters were measured. Greater increases were measured in area 2, where several barges were removed. In both areas, water column concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and several metals exceeded one or more water quality criteria; turbidity levels in area 2 also exceeded regulatory criteria. Potential chemical bioaccumulation from the water column into residential aquatic receptors was estimated using standard models and assumptions. The modeled results predicted that steady-state tissue concentrations of bioaccumulative chemicals would not occur as a result of the brief increase in water column concentrations that occurred during barge removal but that metals and PCDD/Fs could bioaccumulate to levels that exceed regulatory ecological criteria during long-term sediment disturbance activities. In addition, based on some simplistic assumptions regarding settling of suspended sediments, we estimate that chemical bioaccumulation from surface sediments into the food web could result in substantial increases in PCDD/F body burdens in the benthic forage fish, mummichog. Our findings are consistent with the limited number of field studies that have measured increased body burdens of bioaccumulative chemicals following dredging. We suggest that, prior to consideration of extensive dredging as a remedial alternative for any river system, the potential significant and long-term impacts on the food web must be evaluated.  相似文献   

18.
Introduced plants that have both production values and negative impacts can be contentious. Generally they are either treated as weeds and their use prohibited; or unfettered exploitation is permitted and land managers must individually contend with any negative effects. Buffel grass (Cenchrus ciliaris) is contentious in Australia and there has been no attempt to broadly and systematically address the issues surrounding it. However, recent research indicates that there is some mutual acceptance by proponents and opponents of each others’ perspectives and we contend that this provides the basis for a national approach. It would require thorough and on-going consultation with stakeholders and development of realistic goals that are applicable across a range of scales and responsive to regional differences in costs, benefits and socio-economic and biophysical circumstances. It would be necessary to clearly allocate responsibilities and ascertain the most appropriate balance between legislative and non-legislative mechanisms. A national approach could involve avoiding the introduction of additional genetic material, countering proliferation in regions where the species is sparse, preventing incursion into conservation reserves where it is absent, containing strategically located populations and managing communities to prevent or reduce dominance by buffel grass. This approach could be applied to other contentious plant species.  相似文献   

19.
针对干旱生态敏感区水电站环境影响后评价的要求,设计备选指标集,采用频次分析法进行指标初选,采用专家咨询法进行指标精选,建立由4项二级指标、14项三级指标构成的干旱生态敏感区水电站环境影响后评价指标体系,采用层次分析法给每个指标赋予权重.将该评价指标体系用于某水电站建设的实例分析,结果表明,水电站运行以来总体上有利影响大...  相似文献   

20.
The objectives of this study were to assess the biological water of the Iranian Tajan River using different metrics, i.e., a Multimetric Macroinvertebrate Index (MMI) and a traits-based method. Twenty-eight physico-chemical parameters, 10 habitat factors, and abundance of macroinvertebrates were obtained for 17 sites. The Shahid-Rajaie dam divides the Tajan River into an up- and downstream part, with different land uses. Eighteen metrics were used to represent four components of ecosystem quality, including tolerance (Hilsenhoff, SIGNAL), diversity (Margalef, Shannon–Wiener, Simpson, and Evenness), abundance (total number of taxa, individuals, Ephemeroptera, Plecoptera, Trichoptera, EPT, and Insects), and composition of assemblages (% Ephemeroptera, % Plecoptera, % Trichoptera, and % EPT Taxa). The integrated MMI was calculated by averaging the obtained scores of all indices. In the next step, we gathered information on 22 biological traits of macroinvertebrates to evaluate whether (group of) traits could be identified that are indicative for specific or general stress. Result showed a decrease in MMI from upstream (very good water quality) to downstream (bad) due to human activities. Industrial activities like pulping and papermaking operations or sand mining in the downstream part had more effects than agriculture and fish ponds in the upstream part. A redundancy analysis biplot showed the variation between the modalities of trait of macroinvertebrates and their correlation with physico-chemical parameters in Tajan River. The findings show that traits can be indicative for different kind of stress but that more effort has to be put in gathering data sets to disentangle the effect of habitat quality, pollution, and the physico-chemical properties of high- versus lowland rivers.  相似文献   

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