大兴安岭天然落叶松林单木健康评价

单木健康评价结果融入传统小班(或林分)尺度健康评价中,可提高小班(或林分)尺度评价准确性,实现单木尺度与小班(或林分)尺度间的耦合过程,可为实现森林的健康经营提供理论依据.本文以大兴安岭林区天然落叶松林为对象,建立了包括根部状态、树冠落叶程度、树冠透视度、树冠重叠程度、树冠枯梢比重、活冠层比重、树冠偏斜程度和垂直竞争指数的单木健康评价指标体系,根据主成分分析法进行去相关性处理,并使用熵值法赋予指标权重,利用模糊综合评价法对天然落叶松林进行单木健康评价.在评价结果的基础上,采用判别分析法建立单木健康预测模型.结果表明:研究区内处于亚健康等级的林木最多,占总株数的36.7％;健康林木最少,仅占总株数的12.9％;不健康林木比例超过健康林木,达到21.1％;单木健康预测模型预测正确率为86.3％.应采取合理有效的经营措施提高林木的健康等级.     

基于知识粒度的森林生态系统健康评价指标赋权方法

依据系统科学原理,从影响森林健康包括的系统活力、系统组成、系统恢复力和林地环境等方面筛选13个指标构建森林健康评价指标体系;针对健康评价取值未知(无决策属性)的状况,利用粗糙集理论的属性重要度分析各指标因子对森林健康的影响程度,提出将基于知识粒度和属性重要度的森林健康评价指标赋权法。根据二类调查和样地调查数据,以湖南省大围山自然保护区8个次生林群落和2个人工林样地为应用实例,结果表明:森林健康评价指标体系的林分郁闭度、林分蓄积量、叶面积指数等13个指标在大围山自然保护区森林健康评价中的权重与专家打分法得到的结果基本相符,并且对样地进行了评价,其中只有1个处于健康,7个处于亚健康,2个处于不健康。与层次分析法、主成分分析法等赋权方法相比,基于粗糙集的森林健康评价指标赋权法不需要提供任何先验信息,以森林健康系统相关信息为分析依据,直接从反映森林健康的指标数据中挖掘各因子之间的相关性及其重要度,不依赖专家经验,信息量越大,所得权重越客观。该评价指标赋权法真实有效,评价结果更符合客观实际,为森林健康评价和健康经营提供理论依据。     

基于有害干扰的森林生态系统健康评价指标体系的构建

在分析国内外提出的众多森林生态系统健康评价指标的不足后,对评价指标进行研究和筛选。最终在森林生态系统健康评价指标体系的构建上提出了一个新的思路,即从森林火灾、林业有害生物、大气污染、人为有害干扰以及森林生态系统内部的增益干扰5个方面选取20个指标构建森林生态系统健康评价指标体系。其中森林火灾干扰包括平均降水量、平均气温、郁闭度、海拔、坡度、坡向、易燃树种的比例和林道距离8个指标,林业有害生物包括有害生物等级、危害程度和寄主树的比例3个指标,大气污染干扰通过叶片、土壤和污染物的分析测定,人为有害干扰包括森林经营措施、采伐措施和林下植被管理3个方面,而森林生态系统内部的增益干扰由物种多样性、群落结构和近自然度3个指标构成。同时对关键评价指标的意义进行了具体分析。此指标体系摒弃传统的评价观念,结合了近年来影响全国森林健康的几个重要原因,更能准确的反应目前森林生态系统的健康状况。研究思路和方法的提出在一定程度上可以丰富森林生态系统健康评价研究理论与方法体系。     

秭归县防护林健康评价指标体系的建立及应用

以秭归县防护林为研究对象,通过传统生态学调查和相关室内分析,在林分水平上建立了包括林分结构、林分功能、生态环境和健康风险4个一级指标、20个二级指标的防护林健康评价指标体系。在综合相关林分健康评价的基础上,制定防护林健康评价指标优劣等级表,采用Delphi-AHP法设置指标权重,利用生态系统健康综合指数模型计算防护林健康指数,分析秭归县防护林健康状况。结果表明:秭归县防护林健康综合指数的范围在0.5000—0.9000之间,健康指数均值为0.6921,秭归县防护林整体处于亚健康状态;9种防护林类型健康状况排序为:阔叶混交林针阔混交林针叶混交林阔叶纯林马尾松纯林柏木纯林其它针叶纯林经济林灌木林,即是混交林纯林经济林灌木林;秭归县防护林健康指数具有空间变异性,在水平方向上,秭归县辖下乡、镇防护林健康指数从南向北有逐渐递减的趋势,在垂直方向上,防护林健康指数随海拔增高逐渐增大,海拔1000 m以上逐渐降低,健康指数表现出随海拔升高由小变大、又由大变小的变化特点。     

应用物种指示值法解析昆嵛山植物群落类型和植物多样性

生物指示目前被广泛用于各类生态系统恢复的监测和评估、生态系统管理的政策与法规的制定等。本文的目的是采用物种指示值法初步解析昆嵛山植物群落类型及其植物多样性的特点,为进一步开展昆嵛山森林自然恢复评价和森林管理提供参考依据。物种累计曲线分析表明,从昆嵛山自然保护区40块永久性标准样地实际采到的物种占全部物种数（估计值ACE为131.26）的92.9%,显示抽样充分。采用主坐标分析将昆嵛山森林群落进一步划分为六种林分类型,通过物种指示值分析得到了各林分类型的指示物种。其中,黑松、山槐、麻栎是黑松林的指示物种;郁李、赤松、山胡椒是赤松林的指示物种;日本落叶松/刺杉林的显著指示物种包括日本落叶松、水榆花楸、刺杉、白檀和水蜡。针叶树－麻栎混交林的指示物种是麻栎;而针叶树－杂木混交林的指示物种构成复杂,如粘鱼须、楸树、华山松,等。阔叶林的物种组成很不相同,分别有枫香林、麻栎林、刺槐林、和水榆花楸林。综合比较不同林分类型乔灌草的整体多样性特点表明,6种林分类型的物种多度和物种丰富度无显著差异;阔叶林的Fisher α指数（P< 0.001）、Shannon–Wiener指数（P = 0.001）,Simpson指数（P = 0.034）与其它5种林分类型相比差异显著;其他五种林分类型的Fisher α指数和Shannon–Wiener指数无显著差异,但Simpson指数在这些林分间差异显著。昆嵛山林分类型的多样性与30年前树种引进和人工造林等人为干扰密不可分。     

抚育间伐对侧柏人工林及林下植被生长的影响

抚育间伐是森林经营管理措施之一,是对森林生态系统的人为干扰。研究不同抚育方式、强度和频率对森林生态系统的干扰对重建、恢复森林生态系统固有功能及实现森林可持续经营管理有重要意义。以31块北京地区侧柏人工林样地对不同抚育强度后侧柏林生长、林下植被生长及林下植物多样性变化进行了研究。研究结果表明:侧柏林分经不同强度抚育后单木胸径、树高、冠幅和林分蓄积生长均增加,不同抚育强度下单木胸径、树高、冠幅生长量和林分蓄积生长量与立地条件有关,好的立地条件宜采取强度抚育,较差立地条件宜采取中弱度抚育;侧柏林分经弱度、中度抚育后林下植物种类增加,经强度抚育后减少;不同强度抚育后林下植物Simpson多样性指数和Shannon-Wiener多样性指数随时间增大,后者对抚育强度更为敏感;林下灌草生物量随抚育强度增大而增加,并随时间增加;侧柏人工林生态系统种间竞争程度与立地条件有关,好的立地条件能够经受较强的人为干扰,差的立地条件受弱度干扰就会打破种间生长平衡。     

长白山阔叶红松林结构多样性的初步研究

在林业可持续发展的背景下,对森林实施生态系统管理,必须保护和维持森林的生物多样性。这就要求在森林调查和经营过程中增加林分结构多样性方面的内容,因此必须充分认识森林结构包括的内容,并研究制订简便实用的结构多样性指标。本文采用目测分层盖度结合无样地点四分法取样进行林分结构因子调查,设计了一套简便的林分结构指标体系,并对长白山红松阔叶混交林及其次生林进行了林分结构多样性的测定研究。结果表明：基于分层盖度构建的林分垂直多样性指数和水平结构异质性指数,可以较好地表示林分的基本结构特征,同时借助点四分法测定的物种多样性指数和对倒木、站干、林隙等的统计,可以较全面地描述阔叶红松林的林分结构因素。应用该方法测定不同的原始林样地的林分结构,得到的林分结构指标与其他林分结构因素的描述,同常规林学调查结论一致并更全面;同时对不同采伐方式的林分结构进行了测定,结合相应的常规指标测定对比,表明该结构指数不但能较好地表示群落的空间结构特征,同时也能对比不同经营方式对林分结构造成的影响,如择伐方式比皆伐方式对林分的结构影响相对较小而且结构恢复时间较短,从而说明对阔叶红松林这种复层异龄混交林的森林类型而言,择伐是一种更适合的通过结构调控进行生态系统管理的方式。在对生态系统进行经营管理过程中,采用该方法能有效地说明林分的垂直结构复杂性和水平结构异质性及重要的林分结构因子存在状况,因而更适合当前森林生态系统管理的要求。文章进一步分析了林分结构指标待改进的部分与研究方向。     

秦岭松栎混交林群落的稳定性

松栎混交林是秦岭最为典型的森林类型之一,其稳定性程度对于秦岭生物多样性维持、水碳平衡及气候调节等至关重要。以秦岭火地塘林区松栎混交林28个样地为研究对象,对28个群落指标进行调查,通过主成分分析,得出稳定性综合指数值(F)并进行Ward聚类,采用Mantel-最优聚类簇数分析确定最优聚类簇数,对通过F值聚类的样地进行分组划分,确定稳定性等级。结果表明:松栎混交林的稳定性分为3个等级,稳定性高的样地:F值在0.66—1.13之间,平均林龄58a,占样地总数的39.3%;稳定性中等的样地:F值在-0.28—0.34之间,平均林龄46a,占样地总数的42.8%,稳定性低的样地:F值在-2.34—-1.26之间,平均林龄42a,占样地总数的17.9%。前3个主成分中灌木层、草本层多样性指数、海拔、土壤水分物理指标,林分密度和优势树种胸径荷载较大,是影响群落稳定性的主要因子。F值与乔木层Shannon-Wiener指数、灌木层Simpson指数、草本层物种丰富度线性拟合均达到极显著水平(P0.01),与海拔和坡度多元曲线拟合达到极为显著的水平(R2=0.786,p0.0001)。在海拔1212—1708 m,坡度31—49°的生境,松栎混交林的稳定性较大,在海拔1900 m以上的生境,松栎混交林稳定性较低。     

可持续经营框架下阔叶红松林区生物多样性间接评价体系的研究

森林生物多样性的保护和持续利用是森林可持续经营的重要内容,如何快速有效地评价生物多样性是当前森林经营实践中面临的重要问题。本文以可持续发展为指导思想,针对阔叶红松林区森林可持续经营中的生物多样性保护问题,提出了一套生物多样性间接评价的体系和评价方法。生物多样性间接评价的基本原理是以物种与生境的关系、森林自然干扰状况、物种间的相互关系和对特殊生境及敏感物种的考虑等为基础的。依据阔叶红松林区的干扰状况、林分一般状况、立木层、灌木层、草本层、附生植物和藤本植物等的特点,采用重复累加的方法,制定了阔叶红松林区林分生物多样性间接评价的打分表。在一个森林经营单位(林业局或林场)进行生物多样性的保护时,首先应根据不同森林类型对干扰的适应和抵抗力大小确定对各类森林优先保护的次序,然后再在各类森林的不同小班中进行生物多样性间接评价打分表的填写,最后根据不同小班生物多样性得分的多少确定其保护的等级或先后次序。生物多样性间接评价调查可以结合森林经理调查来进行。     

丰林自然保护区景观生态评价： 量化与解释

丰林国家级自然保护区是我国目前原始天然红松生态系统保存最完整、面积最大的天然林集中分布区.本研究根据景观分类图、各景观类型的属性数据库及1997年186个样地系统空间抽样数据,选用多样性、自然性、代表性、稀有性、面积适宜性、稳定性和人类干扰7项指标,建立2个层次的生态评价指标体系,运用层次分析法对生态评价因子的等级化处理,评价指标权重的确定,计算出各生态评价因子的综合评价指数（CEI）.结果表明,区内有高等植物113科568种、高等动物近220种,物种多样性赋分3分;保护区地带性顶极植被类型：椴树红松林、枫桦红松林、云冷杉红松林,隐域性顶极群落云冷杉林以及仍具有原始林性质的针阔混交林、针叶混交林面积占森林总面积的90.0％和森林总蓄积的96.6％,代表性赋分3分;近20～30年内未受到强烈的外界干扰（人为和自然的）,自然生境完好,次生化演替得到有效控制,自然性和人类干扰赋分4分;原始森林植物仍保存着很多古老第三纪的孑遗种,如红松、水曲柳、核桃楸、黄檗、紫椴和色木槭等,稀有性赋分4分;保护区总面积18 165 hm²,其有效面积大小适宜,足以维持生态系统的结构和功能,面积适宜性赋分4分;保护区以红松为主体的红松混交林是一个稳定的群落,稳定性赋分4分.综合评价结果,该保护区生态质量CEI为0.87,表明其生态质量很好,保护价值高,在东北地区乃至全国均有典型的代表意义.目前保护区的面积、结构及经营管理能满足其可持续发展的需要.     

生物化学课程“四化”形成性考核体系的构建与实践

课程考核是评价课程教与学效果的重要方式,在人才培养过程中发挥了指挥棒的作用。本文针对目前我国高等院校课程考核普遍存在的主要问题,以生物类专业基础课程“生物化学”为载体,通过文献研究、调查反馈和实践检验等方法,探索构建并实践“四化”形成性考核体系。其中考核主体的扩大化在主体范畴和考核载体两层面进行构建,考核过程的动态化在过程节点和反馈时效两个层面进行构建,考核内容的生态化在面向个体和群体两个维度进行构建,考核方式的多元化在考核形式、考核方法和计分方式三个层面进行构建。经过我校6个专业的6轮优化实践,对学生的学习和教师的教学均产生显著促进作用。     

Harmonization: Developing Consistent Guidelines for Applying Mode of Action and Dosimetry Information to Cancer and Noncancer Risk Assessment

The 1983 book, Risk Assessment in the Federal Government: Managing the Process, recommended developing consistent inference guidelines for cancer risk assessment. Over the last 15 years, extensive guidance have been provided for hazard assessment for cancer and other endpoints. However, as noted in several recent reports, much less progress has occurred in developing consistent guidelines for quantitative dose response assessment methodologies. This paper proposes an approach for dose response assessment guided by consideration of mode of action (pharmacodynamics) and tissue dosimetry (pharmacokinetics). As articulated here, this systematic process involves eight steps in which available information is integrated, leading first to quantitative analyses of dose response behaviors in the test species followed by quantitative analyses of relevant human exposures. The process should be equally appropriate for both cancer and noncancer endpoints. The eight steps describe the necessary procedures for incorporating mechanistic data and provide multiple options based upon the mode of action by which the chemical causes the toxicity. Given the range of issues involved in developing such a procedure, we have simply sketched the process, focusing on major approaches for using toxicological data and on major options; many details remain to be filled in. However, consistent with the revised carcinogen risk assessment guidance (USEPA, 1996c), we propose a process that would ultimately utilize biologically based or chemical specific pharmacokinetic and pharmacodynamic models as the backbone of these analyses. In the nearer term, these approaches will be combined with analysis of data using more empirical models including options intended for use in the absence of detailed information. A major emphasis in developing any harmonized process is distinguishing policy decisions from those decisions that are affected by the quality and quantity of toxicological data. Identification of data limitations also identifies areas where further study should reduce uncertainty in the final risk evaluations. A flexible dose response assessment procedure is needed to insure that sound toxicological study results are appropriately used to influence risk management decision-making and to encourage the conduct of toxicological studies oriented toward application for dose response assessments.     

Integrated Risk Assessment — Results from an International Workshop

The World Health Organization's International Programme on Chemical Safety and international partners have developed a framework for integrated assessment of human health and ecological risks and four case studies. An international workshop was convened to consider how ecological and health risk assessments might be integrated, the benefits of and obstacles to integration, and the research and mechanisms needed to facilitate implementation of integrated risk assessment. Using the case studies, workshop participants identified a number of opportunities to integrate the assessment process. Improved assessment quality, efficiency, and predictive capability were considered to be principal benefits of integration. Obstacles to acceptance and implementation of integrated risk assessment included the disciplinary and organizational barriers between ecological and health disciplines. A variety of mechanisms were offered to overcome these obstacles. Research recommendations included harmonization of exposure characterization and surveillance methods and models, development of common risk endpoints across taxa, improved understanding of mechanisms of effect at multiple scales of biological organization, and development of methods to facilitate comparison of risks among endpoints.     

Approaches for Integrated Risk Assessment

Recognizing the need to enhance the effectiveness and efficiency of risk assessments globally, the World Health Organization's International Programme on Chemical Safety, the U.S. Environmental Protection Agency, the European Commission, and the Organization for Economic Cooperation and Development developed a collaborative partnership to foster integration of assessment approaches used to evaluate human health and ecological risks. The objectives of this effort included: improving understanding of the benefits of integration, identifying obstacles to the integration process, and engaging key agencies, organizations, and scientific societies to promote integration. A framework with supporting documentation was developed to describe an approach for integration. Four case studies were constructed to illustrate how integrated risk assessments might be conducted for chemical and nonchemical stressors. The concepts and approaches developed in the project were evaluated in an international workshop. The goal of this effort was international acceptance of guidance for integrated risk assessment.     

投影寻踪模型在区域生态环境质量评价中的应用

大量相关因子的简化和降维处理是生态环境质量评价的关键问题之一。而投影寻踪模型可将多个指标投影到线性空间,实现指标的降维处理。本文以巢湖流域生态环境质量综合评价进行了实证分析,巢湖流域生态环境质量为3级,其中合肥市和六安市所属区域生态环境质量为3级,巢湖市为4级。研究表明,应用投影寻踪模型进行区域生态环境质量评价人为干扰少,操作简便,便于在生产实践中应用,为区域生态环境质量评价提供了一条新途径。     

The Fox River Risk Assessment Teaching Tool

In 1999 and 2000, two environmental consulting companies independently prepared risk assessments of the Lower Fox River waste site in Wisconsin. Because the two assessments produced somewhat different risk characterizations, the Association for Environmental Health & Sciences was asked by the site's Potentially Responsible Party to form a peer review panel to critique and compare the two assessments. The panel found interesting differences between the two risk assessments and recommended that their observations, together with the two risk assessments, be made available as a Teaching Tool for persons interested in conducting human and ecological risk assessments. An accompanying CD contains these and other materials useful for teaching purposes.     

Human Health Risk Assessment: Required Reading

Over the past 30 years, risk assessment has developed into a scientific discipline. It is critical that the next generation of risk assessors understand the history of our field, and recognize the numerous successes and failures that have taken place. This short Perspective identifies and describes specific books, monographs, and reports that are required reading for any nascent risk assessor.     

Microbial Endpoints: The Rationale for their Exclusion as Ecological Assessment Endpoints

The functional importance of bacteria and fungi in terrestrial systems is recognized widely. However, microbial population, community, and functional measurement endpoints change rapidly and across very short spatial scales. Measurement endpoints of microbes tend to be highly responsive to typical fluxes of temperature, moisture, oxygen, and many other noncontaminant factors. Functional redundancy across broad taxonomic groups enables wild swings in community composition without remarkable change in rates of decomposition or community respiration. Consequently, it is exceedingly difficult to relate specific microbial activities with indications of adverse and unacceptable environmental conditions. Moreover, changes in microbial processes do not necessarily result in consequences to plant and animal populations or communities, which in the end are the resources most commonly identified as those to be protected. Therefore, unless more definitive linkages are made between specific microbial effects and an adverse condition for typical assessment endpoint species, microbial endpoints will continue to have limited use in risk assessments; they will not drive the process as primary assessment endpoints.     

Impact assessment for LCAs involving agricultural production

LCA has been developed primarily for industrial production systems. Application to agricultural systems requires systematic application of existing methodology and new methodological developments. Conventional approaches can obscure potential options for improving the environmental performance of systems involving agricultural production due to use of restricted system boundaries, incomplete assessment of impacts, and exclusion of ancillaries from the analysis. For use of nutrients such as phosphorus, it is proposed that Impact Assessment should be based on the quantity dispersed after use rather than on the input to the productive system. Eventually, the impacts associated with depletion should be based on technological or thermodynamic assessment of concentration for reuse, but this approach requires further theoretical development.