共查询到18条相似文献，搜索用时 109 毫秒
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对长江经济带湿地生态系统的健康状况进行综合评价并预测分析,为该湿地可持续发展提供依据。以“压力-状态-响应”（PSR）为框架,选取12个指标构建评价体系;采用层次分析法（AHP）计算各项指标的权重,同时将湿地健康状况划分为“健康、亚健康、脆弱、疾病、恶劣”五项;通过综合评价指数（CEI）对其健康进行分析,并利用整合移动平均自回归（ARIMA）模型预测2025年湿地健康状况。结果表明：长江经济带湿地健康综合评价指数在2005—2017年从0.475 5增长到0.613 7,健康等级从“脆弱”转变为“亚健康”,到2025年综合评价指数预计超过0.700 0,继续保持“亚健康”状态。在压力、状态、响应三项准则层中,压力子系统有相对风险,状态和响应指标应继续保持湿地生态系统的健康状态;在12个评价指标中,人口自然增长率、湿地面积变化率及自然保护区数、第三产业所占比重和湿地管理水平、生态环境恢复是影响长江经济带湿地生态系统健康状况的最主要因素。 相似文献
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石漠化的地质指标体系 总被引：1，自引：0，他引：1
分析了岩溶石漠化地质指标的概念和特征,从影响石漠化环境的自然因子、人文因子,石漠化发育分布现状和所引发的后果或危害中提取相应的指标,依照影响（Cause）-状态（State）-后果（Result）框架构建了石漠化地质指标体系。探讨了石漠化地质指标的研究内容,包括指标的研究意义、指标变化的原因和指标监测的空间尺度、时间尺度、测量方法。 相似文献
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根据＂压力-状态-响应＂（PSR）框架模型,对南四湖健康状态进行评价。选取南四湖流域人口密度、工农业供水需求、富营养化程度、南四湖生物多样性指数、环保投资指数等能够充分反映南四湖压力、状态和响应的指标构建评价指标体系;通过专家经验赋值法对各评价指标进行权重确定,并对指标进行标准化赋值;提出了南四湖健康评价模型并且得出南四湖的健康综合指数;根据健康综合指数,确定南四湖健康状况。研究结果表明,南四湖健康评价指数为0.4051,南四湖健康处于＂亚健康＂状态。 相似文献
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基于“驱动力-压力-状态-影响-响应”（DPSIR）系统模型,分别从水资源、经济社会和生态环境等方面选取22个评价指标,建立了沂河水资源可持续利用评价指标体系,运用基于层次分析法和熵值法的综合权重法确定各指标权重,采用综合指数法进行水资源可持续利用评价。研究表明：沂河水资源可持续利用综合评价值介于0.478～0.633,可持续利用水平为基本可持续,准则层以影响评价值最高,其次是状态、压力、驱动力和响应。通过实际调研可得,评价结果与流域实际情况基本相符。近年来,沂河水资源可持续利用水平逐渐提高,但未来仍需通过加大政府水利投入、增强人民环境保护观念等措施,提高沂河水资源可持续利用水平。 相似文献
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川西北江河源区位于四川西北部,其境内的草地有着十分高的生态服务和社会服务价值。以其作为研究区域,利用2001年-2010年MODIS植被指数数据,通过GIS的空间分析和地统计分析功能,得到10年内江河源区植被覆盖度。同时,使用四川省高寒草甸草地生物量模型在MODIS植被指数的基础上反演了2001年-2010年川西北江河源区草地生物量。综合草地植被覆盖度和草地生物量指标,建立了川西北草地退化状况分级评价体系。结合研究区DEM数据对草地退化状况的空间分布进行了分析,结果表明:(1)草地退化率与海拔高度呈反比关系,海拔越高,退化率越低,反之,退化率越高;(2)草地退化率随着坡度的增大呈缓慢升高状态,在32.28°退化率达到最大,之后退化率开始出现降低趋势;(3)草地在各坡向上的分布面积虽有高有低,但退化率变化不大。 相似文献
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基于DPSIRM框架模型的高原湿地生态安全评价 总被引：2，自引：0，他引：2
综合考虑高原湿地生态安全的资源、 环境、 生态、 社会、 经济等影响因素， 以驱动力-压力-状态-影响-响应-管理（DPSIRM）框架模型建立高原湿地生态安全DPSIRM评价指标体系， 采用灰色关联法对各评价指标赋权重值， 运用集对分析法建立评价模型， 对威宁草海2011 - 2016年的湿地生态安全进行评价研究。结果显示： 人口自然增长率、 单位工业产值废水排放量、 生活污水排放量、 化肥施用强度、 农药施用强度、 人均水资源量、 物种多样性、 水土流失率、 物质生产、 湿地面积退化率、 污水处理率、 物质生活指数、 环保投资指数和政策法规实施力度等是影响威宁草海湿地生态安全的主要因素； 威宁草海湿地生态安全逐渐转好， 2011 - 2012年草海湿地生态安全属于不安全等级， 2013 - 2016年属于临界安全等级； 从各子系统情况看， 驱动力子系统为较安全等级， 压力、 状态、 影响、 响应和管理子系统均为临界安全等级， 响应子系统为不安全等级， 成为影响威宁草海湿地生态安全的重要系统。研究成果可为威宁草海湿地的生态安全和环境建设提供科学参考。 相似文献
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地质环境问题的地质指标体系框架及其构建方法 总被引：1，自引：0，他引：1
面对复杂、多变、脆弱的地质环境和不断加剧的人类工程经济活动,急需建立面向多种地质环境问题的地质指
标体系。针对中国地质环境工作现状,借鉴国际地质指标工作组最新的成果和经验,对地质指标的定义、内涵进行了
修订和拓展,创建了包括调查指标体系（影响指标、状态指标、后果指标）和监测指标体系（压力指标、状态指标、
响应指标）的地质指标体系框架,并建立了从面向单一地质环境问题的地质指标体系的构建思路、实际范例,到面向
一个国家或地区的地质指标体系的构建步骤,为地质指标的创建、完善和应用指明了方向。 相似文献
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2005-2015年贵阳市生境退化程度对土地利用变化的响应 总被引：1，自引：1，他引：0
基于2005和2015年贵阳市土地利用数据,利用InVEST模型,分析了2005-2015年贵阳市生境退化程度对土地利用变化的响应,结果表明:（1）2005-2015年贵阳市城镇建设用地、农村居民点和有林地大幅增加,水田和旱地大幅下降,其他地类变化相对较小;水田和旱地转化为城镇建设用地、农村居民点和有林地最为突出;（2）10年间,贵阳市生境退化程度以下降为主,生境退化程度增加区主要分布在南部,下降区主要分布在北部、东部和西部;（3）生境退化程度热点变化以低值减少和高值减少为主;生境退化程度热点空间变化主要分布于南部。退耕还林政策及快速城镇化引起的水田和旱地转化为有林地、城镇建设用地和农村居民点是导致该区生境退化程度变化的主要因素。 相似文献
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随着全球城市化进程的不断加快,城市水土环境变化日益引起人们的关注。借鉴国际地质指标研究的思路,有针对性地构建了城市水土环境变化的地质指标体系。首先明确了城市水土环境的概念内涵,确定了指标体系构建的原则,在此基础上提出了融合“CSR模型”和“PSR模型”的指标体系框架,在此框架指导下构建了城市水土环境变化调查指标体系和监测指标体系,二者共同构成了城市水土环境变化地质指标体系,为城市水土环境调查、监测与管理提供了前期的技术支撑。 相似文献
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Fazel Amiri Abdul Rashid bin Mohamed Shariff Taybeh Tabatabaie Biswajeet Pradhan 《Arabian Journal of Geosciences》2014,7(3):1101-1114
Extensive livestock grazing even in unsuitable land has increasingly grown in most parts of semi-arid rangeland. Therefore, it is of paramount importance to identify suitable land for livestock grazing for optimum utilization while causing minimum impact to the environment. This paper adapted the schematic model based on the concepts presented by the Food and Agriculture Organization of suitability analysis for optimal grazing management in semi-arid rangeland in Iran. Factors affecting extensive grazing were determined and incorporated into the model. Semi-arid rangeland with variable such as climate and other agents were examined for common types of animal grazing and the advantages and limitations were elicited. Many ecosystem components affect land suitability for livestock grazing but due to time and funding restrictions, the most important and feasible elements were investigated. Within the model parameters, three submodels including water accessibility source, forage production, and erosion sensitivity were considered. Suitable areas at four levels of suitability were determined using geographic information systems. This suitability modeling approach was adopted due to its simplicity and the minimal time required for transforming and analyzing datasets. The most important reducing factors in model suitability were found to be: (a) land use and vegetation cover (in relation to soil erosion sensitivity), (b) the amount of the available forage in comparison with the total production, and (c) the existence of less palatability plants among the pasture plant species (forage production suitability). The results of the study would be beneficial to rangeland managers in devising measures more wisely to cope with the limitations and enhance the health and productivity of the rangelands. 相似文献
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This paper presents a joint constitutive model that considers separately the mechanical contribution of waviness and unevenness of a joint to shear behaviour. The critical asperities for waviness and unevenness are determined from geometric properties in a lab-scale joint. The wear process is employed to model the degradation in dilation and strength during shear. From dimensional analysis, asperity degradation constants are developed using geometric parameters including asperity angle, wavelength, and amplitude as well as rock strength and stress. The applicability of the proposed model was assessed by performing direct shear tests on three joint roughness coefficient (JRC) profiles and providing its correlation with experimental results. Additionally, experimental data taken from literature were used to validate the model’s performance. 相似文献
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Soil is a dynamic natural body and fundamental resource. Human activities influence intensively the natural processes in soils.
They modify and accelerate the development of soils. In this investigation, the deposition of colluvial sediments (colluviation)
and soil formation are proposed as geoindicators for a better understanding of long-term environmental changes and environmental
impact assessment. Deposition of colluvial sediments during several time periods and subsequent soil formation under different
land-use systems reflect important aspects on the long-term human interference in the environment. In this study, we hypothesize
that intensive human activities and environmental changes during middle and late Holocene are responsible for a strong modification
of soils in an investigation area in Schleswig–Holstein (Germany). Soil age information together with geomorphological data,
physical, chemical and biological soil properties provide the database which is necessary to study the types and rates of
colluviation and soil formation. After the investigation with a high resolution in time and space, results show that middle
and late Holocene land-use changes and land management are responsible for soil formation in colluvial layers. Properties
of soils and sediments vary intensively from Mesolithic until Modern times. Intensive soil formation took place during periods
of geomorphodynamic stability in dense woodland. Evidence in our investigations shows that colluviation has a strong relation
with decision-making and environmental degradation in the past. This confirms, too, that a geoindicator concept is needed
to understand and to monitor long-term environmental changes and degradation. 相似文献
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Implication of coupled natural and human systems in sustainable rangeland ecosystem management in HKH region 总被引：1，自引：0，他引：1
The sustainable development of rangeland ecosystems, the vital ecosystems providing many important ecosystem services for
millions of people in the Hindu Kush-Himalaya region is presently confronted with a number of challenges. A coupled natural
and human systems approach is needed to facilitate effective collaboration among social scientists, bio/physical scientists,
and management practitioners to better understand how people interact with the environment in which they live. In pursuing
this argument, three existing case studies, i.e. Indigenous rangeland management in Himalayan Nepal, Cultivated Grassland
Systems in Eastern Qinghai-Tibetan Plateau, and Grassland Restoration in Central Qinghai-Tibetan Plateau were synthesized
in this paper to address the importance of coupled natural and human systems in promoting sustainable rangeland ecosystem
management in the Hindu Kush-Himalaya (HKH) region. It was concluded although the research sites and objectives were very
different, that these three case studies had many commonalities that addressed the complex interactions and feedbacks between
natural and human systems, and highlighted the integration of various tools and techniques from the ecological and social
sciences, as well as other disciplines, in sustainable rangeland management. These case studies have offered unique interdisciplinary
insights into complexities that cannot be gained from ecological or social research alone. The results from these case studies
can be applied to many other coupled systems at local, national, and global levels. 相似文献
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好氧降解作用对垃圾土沉降变形特性的定量评价是预测和评估好氧降解稳定化的重要基础。以武汉市典型生活垃圾组成配比人工制作的垃圾土为样本,开展了不同通风条件下垃圾土沉降特性试验,分析了好氧通风频率对沉降变形的影响。试验结果表明：厌氧条件沉降速率趋于稳定后,好氧通风可显著提高垃圾土的沉降速率;上、中、下3层垃圾在高通风频率下垃圾土沉降比低通风频率下沉降效率分别提高了145%、150%、100%;建立了厌氧-好氧联合型沉降模型,通过与试验监测得到的沉降值对比,初步验证了模型的可靠性。研究结果为好氧通风过程中垃圾土沉降稳定性评估提供了理论依据。 相似文献
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重大建设项目对施工过程中岩土体稳定性提出了更高的要求,常以一种动态设计施工模式来应对工程体的各类突发状况与病害。流变损伤模型既能反映岩土体在施工过程中变形的时效发展,又能反映其力学性质的时效劣化,继而能较准确地掌握工程体动态稳定性。基于以上考虑,为体现卸载边坡工程在卸载回弹阶段的瞬时塑性特征和时效演化阶段的黏塑性特征,因此,在流变模型中引入加载塑性元件和黏塑性元件,建立了复合黏弹塑（弹-黏-黏弹-黏塑-塑）模型,室内岩石压缩（卸载）蠕变试验证明了该流变模型的合理性,并对其参数进行辨识。在此基础上,从几何研究方法出发,引入反映节理分布的初始损伤张量及一种等效的依据黏塑性偏应变推导出的损伤演化方程,最终建立了一种新型的节理岩体等效流变损伤模型。将此模型用于川东红层某软硬岩互层型路堑边坡的卸载分析,结果表明：随不同的开挖阶段,易损部位（软岩集中段、软岩深埋段、软硬交接硬岩段）在瞬时卸载回弹阶段的塑性损伤和时效演化阶段的黏塑性损伤逐渐积累,边坡浅表部逐渐出现卸载损伤（松弛）带,在损伤累积中边坡各部位蠕变速率呈不同程度的增长。计算结果较好地反映了边坡变形、损伤发展与动态稳定性特征,其研究结果对于指导支护时机及相应的信息化施工具有一定的意义。 相似文献