外来植物的入侵机制及其生态风险评价

外来植物入侵已成为严重威胁生态系统健康发展的全球性问题,预防优于治理,对外来植物进行生态风险评价可有效地防御和降低入侵风险。本文基于生态风险评价理论,通过对外来植物入侵特性和过程的分析,探讨了外来植物入侵生态风险的评价方法。将评价程序分为风险源分析、风险受体评价、暴露与危害评价、风险综合评价和风险管理对策5部分,初步建立了风险源评价指标体系,以及度量生态损失和生态风险的指标和公式,进而得出外来植物入侵综合生态风险评价的方法。     

生态风险评价研究进展

生态风险评价有效整合了学术研究、政策制定和生态环境管理,越来越多地被应用到生态环境问题的解决。生态风险评价研究历经20多年发展历程,风险源从单一风险源扩展到多风险源,风险受体从单一受体发展到多受体,评价尺度也从种群、生态系统扩展到区域和景观水平。但已有研究中,风险受体大部分还停留在生物个体或种群水平,风险受体尺度有待扩展,定性或者半定量研究方法亦难以适应现有研究尺度以及综合性评价的要求,因此,基于区域可持续发展视角的大尺度、综合性定量评价方法和模型将成为未来研究的重点。     

基于生态系统服务的生态风险评价研究进展

生态风险评价对科学管理与保护生态系统具有重要的意义,为弥补传统生态风险评价方法的不足和提高风险管理的效率,将生态系统服务引入生态风险评价中进行发展和完善,成为了当前生态风险评价研究的前沿和热点。系统分析了生态系统服务在生态风险评价中的应用,指出生态系统服务在问题形成阶段中可明确保护对象和属性,在风险分析阶段可联系生态系统结构过程作用,在风险表征阶段及后续阶段能可提供清晰明确的评价结果,加强风险交流和管理,能有效地改进生态系统传统生态风险评价。在实践上,基于生态系统服务的生态风险评价可从3个不同层面开展:一是针对外界压力对某类特定功能或者系统中某些服务功能的影响,构建基于某种特定服务的实体属性评价方法;二是针对外界压力作用下生态系统结构与过程变化下对功能影响,构建基于复杂生态系统作用的评价方法,实现对生态风险的模拟评价;三是评价社会生态系统下外界驱动对人类福祉的影响时,可将DPSIR(Drive-Pressure-State-Impact-Response)理论模型运用到生态风险管理中,也可基于景观生态系统服务与压力源的空间作用关系,实现社会生态系统风险评价与管理。作为生态风险表征手段,可基于生态系统服务损失与不利服务进行表征,也可选取热力学等指标作为评估量纲。从理论、评价方法、风险管理等方面对基于生态系统服务生态风险评价给予展望。     

基于土地破坏的矿区生态风险评价:理论与方法

矿区生态风险评价已成为区域生态风险研究的热点领域。如何合理选择和表征区域生态风险源和风险受体,量化多风险源和多风险受体的交互作用,是目前区域生态风险评价研究的焦点。为此,在总结矿区生态风险评价研究成果的基础上,构建了矿区生态风险源、风险受体及作用对象与过程的因果链模型,结合矿区生态环境问题产生过程的独特性,将土地挖损、占用及塌陷等土地破坏作为矿区的直接生态风险源。基于土地破坏类型提出了适宜矿区的区域生态风险评价流程、指标体系与计算方法;并专门在定量化多风险源与多风险受体交互作用上做出探讨,构建了生态系统单元暴露指数和土地破坏累积作用指数来评价矿区土地破坏与生态系统单元间的暴露与危害作用关系。为矿区生态风险评价的实证研究提出了理论基础与方法框架,未来可结合实证研究对此方法及相关指标参数做出完善与改进,为矿区生态环境管理与生态安全建设提供科学的参考依据。     

城市生态风险管理关键问题与研究进展

我国目前正处于社会经济转型和城市化进程加快时期,随着城市化发展和城市人居环境的变化,城市生态风险受到越来越多关注。在综述国内外城市生态风险管理研究进展,总结风险源与受体特点和风险评价方法的基础上,结合城市生态风险管理的需求,明确了城市生态风险的管理目标,将管理目标系统归纳划分为控制目标、调控目标和规划目标3个层次;在解析城市生态风险管理特点的基础上,结合风险管理目标从弹性力、动态管理性和空间异质性3个方面对生态风险管理措施与方案进行了总结分析,并进一步探讨了风险管理保障机制。从生态风险管理目标制定、构建城市生态系统特点的风险管理体系及其管理机制等方面提出了建议与展望,以期推动我国城市生态风险管理的发展。     

中国森林健康生态风险评价

我国森林每年都在遭受诸如过度砍伐、火灾、病虫鼠害、酸雨、气象灾害等各种形式的干扰．这些干扰对我国森林生态系统的健康状况造成很大的威胁．因此,如何有效地管理我国的森林资源,特别是对森林的生态风险管理,提高森林生态系统抵御风险的能力,是森林生态系统健康研究和森林可持续管理的首要任务之一．森林健康生态风险评价是描述和评价人为活动、自然灾害和环境污染等胁迫因子对森林生态系统结构和功能、森林生态系统的健康状况产生不利影响的可能性和危害程度的评估,是森林资源管理的一个重要环节．以我国森林生态系统为例,探讨森林健康生态风险评价的研究方法,并以森林火灾、病虫害和酸雨为生态风险源,运用生态风险评价方法,分析了这些风险源对森林健康的主要危害,对我国森林健康的风险进行了综合评价,并提出不同森林风险区的管理策略．     

区域生态风险评价的关键问题与展望

区域生态风险评价具有多风险因子、多风险受体、多评价终点、强调不确定性因素以及空间异质性的特点,它与传统的生态风险评价在风险源、胁迫因子和评价尺度上具有明显区别。尝试建立了一个基于陆地生态系统的区域生态风险评价框架,同时针对目前区域生态风险评价的研究现状,指出不确定性分析、尺度外推难、评价指标不统一、评价标准不统一、风险因子筛选及优先排序、区域内污染物复合、水生过渡到陆生生态系统风险评价、特殊的人为因素等是目前区域生态风险评价存在的关键问题及难点所在,并提出解决这些问题可能所需的工具、手段和理论方法突破。最后指出区域生态风险观测与数据采集加工、区域生态风险指标体系的统一与整合、区域生态风险评价方法论、区域生态风险的空间分布特征与表达以及区域生态风险评价反馈与管理机制5个方面是区域生态风险评价未来的研究重点。     

城市滑坡灾害生态风险不确定性分析及风险管理——以深圳市为例

城市化的快速推进加剧了建设活动强度,强烈改变自然地表,破环原本稳定的地质环境,导致滑坡灾害日益频繁。本研究以深圳市为研究区,基于"危险性-脆弱性-潜在损失"三维评价框架评价深圳市街道尺度滑坡灾害生态风险、运用"三基色"原理可视化风险结构,并采用蒙特卡洛模拟进行不确定性分析,进而提出生态风险管理措施。结果表明:(1)不确定性与街道面积呈显著的负相关关系,随着街道面积增加,生态风险源不确定性减少;(2)以风险源为不确定性主体的生态风险评价中,不确定性由生态风险源不确定性和"源外"因子大小共同主导,"源外"因子大小是生态风险评价不确定的敏感因素;(3)深圳市滑坡灾害生态风险从西到东呈现"低-高-低-高"交错结构,风险结构主要为"高脆弱-高潜在损失"型和"高危险-高潜在损失"型。分析生态风险结构,建立滑坡灾害生态风险管理体系,制定明确风险管理目标,有利于高效地进行生态风险管理。     

基于Citespace软件的生态风险知识图谱分析

伴随着重大环境事件频发,环境污染、生态破坏现象的日益严峻,生态风险研究受到各国学者和政府的广泛关注。对整个生态风险研究领域进行全面系统的分析,旨在探究研究热点及趋势,归纳研究主题演进,了解当前国际研究现状。以Web of Science数据库为数据源,利用Citespace软件,绘制生态风险研究知识图谱,进行文献可视化分析。研究发现:(1)国际生态风险研究的发文数量经历了缓慢增长-平稳增长-迅速增长3个阶段;(2)生态风险研究分为奠基期,成长期,拓展期3个阶段,各阶段研究热点不同,当前研究热点是"空间分布、生态系统服务、城市土壤、源解析、海洋沉积物";(3)生态风险研究由单一风险源、风险受体、小尺度的评价演化为多种风险源、多种风险受体的大尺度综合评价;(4)欧美国家、学者奠定了该领域的研究基础,中国起步较晚但发展迅速。     

生态风险评价研究进展

20多年来,生态风险评价研究经历了从环境风险到生态风险到区域生态风险评价的发展历程,风险源由单一风险源扩展到多风险源,风险受体由单一受体发展到多受体,评价范围由局地扩展到区域景观水平.区域生态风险评价就是大尺度上研究复杂环境背景下包含多风险源、多风险受体的综合风险研究.目前,区域生态风险评价的理论框架已经搭建起来,统计方法多采用相对评价法.区域生态风险评价未来的发展方向为继续加强实验和野外调查,进一步减小不确定性,逐步解决尺度推移问题.区域生态风险评价必须与经济、社会、文化相结合,才能充分发挥它在管理决策中的作用.     

生态风险评价及研究进展

生态风险是当前环境管理研究领域中的一个热点问题,其研究着重关注化学、物理和生物的胁迫因子可能对生态系统或其组分的有害影响.生态风险评价对科学制定环境管理决策有着重要的意义.要对生态系统进行有效地管理,必须预测不利生态影响发生的可能性及后果,减小其对于生态系统或某些组分的损害程度.本文对生态风险评价的研究方法、工具以及研究趋势进行了综述,指出了目前生态风险评价中还需要进一步加强的研究领域,认为在当前城市化水平不断提高的情况下要关注城市生态风险,并针对存在的一些问题提出了今后的研究展望.     

A novel quantitative ecological and microbial risk assessment methodology: theory and practice

Abstract

The environment is a complex system where humans, materials (e.g. pollutants), and ecological (e.g. plants, animals, microbes) and meteorological conditions interact with each other. The impact of humans potentially causes significant damage to either the environment (e.g. oil spills may pollute coastal ecosystems) or turns against humans themselves by favoring the growth of unwanted species (e.g. poor sanitation increases microbial populations that cause the risk of large numbers of humans falling ill). Thus, this paper presents a flexible method for quantifying either ecological risks (i.e. the percentage likelihood of adverse effects on the ecosystem due to its exposure to stressors such as chemicals, fishing, etc.) or microbial risks (i.e. the likelihood of negative effects in humans due to their exposure to microbial pathogens). The method uses population modeling to simulate future changes in the numbers of key-species (e.g. fish, corals, sharks, parasites), in various scenarios including the impacts of humans, adverse weather and risk management. Finally, risk is calculated as the probability of the quasi-extinction or quasi-explosion of key-species over time, and then is categorized so that the risks involved may be better communicated to decision-makers. Using the method is illustrated in three different real cases in Brazil.     

Hormesis and ecological risk assessment: Fact or fantasy?

Hormesis is a widespread phenomenon across occurring many taxa and chemicals, and, at the single species level, issues regarding the application of hormesis to human health and ecological risk assessment are similar. However, interpreting the significance of hormesis for even a single species in an ecological risk assessment can be complicated by competition with other species, predation effects, etc. In addition, ecological risk assessments may involve communities of hundreds or thousands of species as well as a range of ecological processes. Applying hormetic adjustments to threshold effect levels for chemicals derived from sensitivity distributions for a large number of species is impractical. For ecological risks, chemical stressors are frequently of lessor concern than physical stressors (e.g., habitat alteration) or biological stressors (e.g., introduced species), but the relevance of hormesis to non‐chemical stressors is unclear. Although ecological theories such as the intermediate disturbance hypothesis offer some intriguing similarities between chemical hormesis and hormetic‐like responses resulting from physical disturbances, mechanistic explanations are lacking. While further exploration of the relevance of hormesis to ecological risk assessment is desirable, it is unlikely that hormesis is a critical factor in most ecological risk assessments, given the magnitude of other uncertainties inherent in the process.     

Performing Spatially and Temporally Explicit Ecological Exposure Assessments Involving Multiple Stressors

Ecological risk assessments have traditionally focused on estimating risk associated with a receptor's exposure to chemical stressors in abiotic (soil, water, etc.) and biotic (tissues, prey items) media. However, a free-living receptor is also constantly challenged to avoid or minimize adverse effects associated with those physical (e.g., loss of habitat) and biological (e.g., lack of adequate food) stressors that are already a consistent and natural part of its everyday existence. All three stressors, as well as their relative spatial and temporal positions with respect to each other and the receptor, may interact in ways that alter a chemical stressor's relative contribution to a receptor's overall risk. Evidence suggests that better representations of a chemical stressor's true contribution to overall risk would result if spatial, temporal, and multiple stressor interactions were more routinely considered and quantified. However, examples of this occurring in typical ecological risk assessments are rare, due, in part, to a lack of practical and accessible procedures for this purpose. This article outlines a procedure to give ecological risk assessment practitioners greater access to spatial, temporal, and multistressor techniques, describes an implementable spreadsheet-based model for performing calculations associated with this procedure, and discusses the types of ecological, life history, and landscape information needed to parameterize this model.     

大辽河口水环境污染生态风险评估

河口生态系统位于河流入海口,是介于河流和海洋之间的生态交错区,也是人类活动集中的区域。针对目前河口生态风险研究较多沿用陆地生态系统模式,并忽略风险分布的空间异质性等问题,以大辽河口为研究区,建立具有针对性的河口区(河海交错区)生态风险评价模型,以盐度和污染源作为划分河口不同区段的主要因素,对不同水期大辽河口生态风险及其空间分布进行有效评估,探讨河口区生态风险时空分布差异规律。结果表明,大辽河口整体生态风险水平相对偏高(三时段风险平均值为0.56),在0至1的生态风险指数空间中超过中等风险水平;就时间尺度上而言,造成大辽河口区生态风险差异的主要原因是径流量;就空间尺度而言,大辽河口区生态风险空间分布受上游来水携带污染物、下游污染源排放以及入海口门段海水稀释作用三者共同影响。因此,从根本上讲,改善并提高河口区域的生态风险水平,应密切关注人类活动对河口态系统造成的不良影响,并应以提高整个流域整体生态状况为根本目标和途径,这样才有助于从根本上解决产生河口区域生态风险的环境问题。     

Ecological Indicators in Risk Assessment: Workshop Summary

Ecological indicators can be defined as relatively simple measurements that relay scientific information about complex ecosystems. Such indicators are used to characterize risk in ecological risk assessment (ERA) and to mark progress toward resource management goals. In late 1997, scientists from the U.S. Environmental Protection Agency and from the Chemical Manufacturers Association (CMA) held a workshop to explore opportunities for collaborative research and scientific exchange on the development and application of ecological indicators. Several scientific challenges were identified as they relate to problem formulation, exposure and effects assessment, and risk characterization. Chief among these were a better understanding of multiple stressors (both chemical and non-chemical), characterization of reference sites and natural variability, extrapolation of measures to ecologically relevant scales, development of comprehensive, ecosystem-based models that incorporate multiple stressors and receptors, and a consistent system for evaluating ecological indicators.     

区域生态风险管理研究进展

近20a来,随着生态风险评价研究的不断深化,区域生态风险评价的理论和方法日臻完善,与此紧密相关的生态风险管理日益受到了广泛关注.生态风险管理具有基于监控的反馈机制、风险受害者参与、程序灵活非线性化、关注成本效益等共同点.总结了国内外生态风险管理的研究进展,发现近年来生态风险管理的研究多是基于生态风险评价的结果,针对不同的风险类型和等级采取不同的管理措施.国内现有的研究对灾害风险管理的体系、机制建设较为成熟,但区域生态风险管理的机制研究尤其是预警和防范方面研究尚不成熟.基于此,构建了基于风险来临前、风险到来时和风险过后的区域生态风险管理的基本框架,研究结果对生态风险管理理论的构建和实践应用具有重要的意义.     

Ecological Risk Assessment of Provincial Land-Use Overall Planning in China

The method evaluating the ecological risk for provincial land-use overall planning is introduced so as to construct an environment-friendly land-use pattern. The ecological risk degree is determined by risk source intensity and ecological vulnerability degree. In order to quantify them, the calculation process, classification standard, and acceptability analysis are established. With an example, it evaluates the ecological risk of land-use overall planning in Sichuan Province. The results show: (1) the implementation of planning can reduce the potential ecological risk effectively, and the whole ecological risk level is on the decline during the planning period; (2) the spatial difference of ecological risk is significant. However, the basic pattern of ecological risks, which is higher in the east and lower in the west, has not changed after the planning implementation, and the higher risk areas mainly distribute in the economically developed and densely populated areas; (3) according to the spatiotemporal characteristics, the emphasis of ecological risk prevention and control can be identified, and some countermeasures can be suggested in order to decrease the potential adverse effects. The method proposed in the article can provide decision basis for provincial land-use overall planning, and is helpful to ecological risk analysis of other planning.     

Issues in Ecological Risk Assessment of Inorganic Metals and Metalloids

Ecological risk assessment (ERA) is a process that evaluates the potential for adverse ecological effects occurring as a result of exposure to contaminants or other stressors. ERA begins with hazard identification/problem formulation, progresses to effects and exposure assessment, and finishes with risk characterization (an estimate of the incidence and severity of any adverse effects likely to occur). Risk management initially sets the boundaries of the ERA and then uses its results for decision-making. Key information required for an ERA includes: the emissions, pathways and rates of movement of contaminants in the environment; and, information on the relationship between contaminant concentrations and the incidence and (or) severity of adverse effects. Because of specific properties and characteristics of metals in general and of certain metals in particular, a generalized ERA process applicable to organic substances is inappropriate for metals. First, metals are naturally occurring and can arise, sometimes in very high concentrations, from non-anthropogenic sources; organisms can and do adapt to a wide range of metal concentrations. Second, certain metals (e.g., copper, zinc) are essential for biotic health, which means there is an effect threshold for both deficiency and excess, and that standard body burden indices such as bioaccumulation factors (BCFs) can be misleading. Third, metals can occur in the environment in a variety of forms that are more or less available to biota but adverse biological effects can only occur if metals are or may become bioavailable. Fourth, whereas the bioavailability and hence the possibility of toxicity of persistent organic substances are mainly dependent on their intrinsic properties (i.e., lipophilicity), those of metals are generally controlled by external environmental conditions. Examples include pH and ligands, which affect the metal speciation and coexisting cations (e.g., H⁺, Ca²⁺) which compete with the metal ions. ERAs involving metals must include the above four major considerations; other considerations vary depending on whether the ERA is for a site, a region, or is global in scope.