若尔盖高原生态环境恶化与沼泽退化及其形成机制

根据１９９６－１９９８年野外考察与研究获得信息,结合前人研究的资料,论证了若尔盖高原沼泽区生态环境恶化,沼泽退化十分严重,其主要表现为：沼泽旱化,沼泽类型改变,沼泽逆向生态演替,沼泽区沙化,野生动物种类,种群数量减少,土壤质量下降,沼泽水质变劣,草场退化和鼠害猖獗,剖析了沼泽区生态环境恶化,沼泽退化与人类活动干扰,自然因素作用的关系,进而阐明了人类活动干扰是沼泽区生态环境恶化,沼泽退化主要原因。     

青藏高原生态环境问题研究

论述青藏高原生态环境现状和面临的严重问题,从人口、资源和环境角度阐述造成高原严重生态环境问题的自然和社会根源。分析解决高原生态环境问题所面临的巨大的自然和社会经济障碍,给出重新认识和评价高原资源优势的新视点,并提出适合于高原自然和社会经济环境的优先产业。     

气候变化对青藏高原生态环境的影响评价

根据青藏高原16个气象观测台站有关气温和降水的多年数据,分析了近40年来青藏高原的气候变化特征。结果表明,近40年来青藏高原气候变化的总趋势是气温升高,降水量稍有增加。这种气候波动变化,对高原植被、冰雪水及土地沙化都有较大的影响。据预测到2100年青藏高原气温将上升2～3 6℃,降水量在高原中部和东部增加约0～300mm,而在西南部将减少0～500mm。气候的变化使植被群落发生明显的变化,分布界线向更高的海拔高度迁移。也使高原冰川退缩,但未来冰川不一定消失。     

基于景观格局优化的北京市域生态环境保育途径

北京城市空间持续扩张导致对地域生态系统的胁迫不断增强,城镇发展空间和自然生态空间的矛盾日趋尖锐,城市的可持续发展受到制约.如何合理配置城市用地和区域空间资源,使城市与自然的关系重归和谐,已成为北京城市发展必须面临的重要课题.运用生态敏感性与适宜性分析的方法,辨识与诊断北京市域生态系统存在的问题.尝试通过景观格局的整体优化, 实现生态环境的保育,使城镇生态景观斑块镶嵌于自然生态景观基质中,并通过多种类型的生态廊道相连, 提高地域生态系统稳定性,防止城市发展空间无序蔓延,为城市地域生态系统服务功能的正常发挥提供保障.     

青藏高原城镇化与生态环境交互影响关系分析

科学评估青藏高原城镇化与生态环境交互影响的总体状况,对优化城镇化速度和质量,修复和提升生态环境状态具有重要意义。在梳理青藏高原城镇化与生态环境交互影响研究进展基础上,本文尝试构建一套完整的城镇化与生态环境交互影响分析模型体系,实现从综合评价指数分析、耦合协调度量化、耦合类型识别、解耦路径探索到未来趋势预测的全过程解析。以青藏高原及其省域、地级单元多尺度分析对比为手段,尝试厘清尺度之间的差异性,识别出问题区域,并提出针对性的改进措施。研究发现,青藏高原不同尺度间城镇化综合评价指数呈阶段性上升趋势,青海的整体城镇化指数高于西藏;生态环境指数变化趋势不同,青海呈下降态势,西藏则趋向平稳,各地级单元生态环境指数存在分层现象。青藏高原不同尺度城镇化与生态环境耦合协调度总体呈上升趋势,协调类型由失调衰退类向濒临失调衰退类转变,最后转为勉强协调发展类,基本属于城镇化滞后型。城镇化指数与生态环境指数呈现出强脱钩、弱脱钩交互出现的波动态势,说明不同尺度间存在城镇化与生态环境的负相互作用,消极城镇化现象突出。通过预测,青藏高原各地级单元在未来10年内,系统耦合协调度将稳步上升,但各地增长速度将存在显著差距。     

东北山区湿地的保育与合理利用对策

大、小兴安岭和长白山区是东北湿地的主要分布区之一。山区湿地面积452．31万hm^2，以沼泽湿地为主，占山区湿地总面积的76．71％，分布着特有的中营养和贫营养沼泽。山区大面积的森林和湿地是保护东北平原农牧业生产及生态环境的重要天然屏障。在分析湿地主要生态功能及保护利用现状的同时，提出增设湿地自然保护区、加强保护区的有效管理和能力建设、实施对湿地开发项目的生态环境影响评价、建立湿地生态监测试验站、加强湿地科学研究、可持续利用湿地资源及增强湿地保护的经济活力等建议。     

广西土地合理利用与生态环境建设探讨

生态环境的破坏与建设与土地利用是密切相关的，分析了广西土地类型和土地利用现状，探讨了由于土地不合理利用导致的生态环境问题，提出了通过合理利用土地来建设生态环境的措施。     

三江平原沼泽生态系统中露水凝结研究

通过对三江平原露日季节变化的分析及对毛果苔草沼泽群落中露水的实地观测，探讨了年露日的出现规律及露水凝结量的时空变化。结果表明：三江平原露水出现频率较高的季节是夏秋季(6～9月)，近12年来露日在66～108d／a，平均为95．42d／a；每年露水的凝结存在两个明显的峰值，分别是6月(或7月)、9月；露水量随高度的变化明显，植物冠层高度处的露水凝结量较多；由于沼泽植物茂密，叶面积较大，加之地面粗糙，单位土地面积上在植物及地面实际凝结的露水量远高于相同面积下较光滑的收集器测得的露水量。用杨木棒测得的毛果苔草地表面的露水量为2．83mm／a，折算成单位土地面积上地表面和植物叶片实际凝结的露水量为20．68mm／a，占同期降水量的5．05％。露水是影响水量平衡的重要因子。     

克里雅河流域生态环境变化与水资源合理利用

水是极端干旱区重要的环境资源。由于自然因素的影响,克里雅河历史时期的沙漠化过程表现为水文网系缩短,天然绿洲沦为沙漠;现代环境变化主要由人类经济活动引起,一方面于田绿洲面积扩大,生产发展。另一方面人类不得当的干涉,造成了环境的不利变化,特别是对下游天然绿洲。以流域为单元的国土整治,合理开发利用水资源是确保生态环境稳定的基础。大河沿天然绿洲在探索干旱区环境变化和植物演替中,有特殊意义的自然景观地域,拟建为自然保护区,每年确保1.0-1.5亿m³水量是必需的和可行的。于田绿洲发展与保护区建立是相辅相成的,共寓于统一的流域生态系统之中,搞好土地生态规划,建立合理的农林牧生态结构和布局,搞好流域土地生态系统功能管理,以期取得良好经济效益和生态效益。     

河北省农田环境问题与生态保育

农田生态保育对建立健康的农田生态系统、提高农田综合生产力和保障粮食安全具有重要意义。根据1996—2004年土地调查数据和TM影像解译数据,分析河北省耕地资源的动态变化及重要的环境因子信息,阐述河北省农田数量与质量下降、土壤沙化、水土流失、农田污染、干旱缺水等农田环境问题对保障粮食安全及农业可持续发展的影响。探讨河北省农田生态保育对策,即加强基本农田保护、中低产田改造与培育、农田污染综合防治、优化区域生态环境和强化生态保育的理念。     

西藏高原生态安全研究

西藏高原是青藏高原的主体,其平均海拔达4 727 m,有"地球第三极"之称,生态环境十分脆弱,高原地形与生态屏障作用对我国乃至亚洲地区生态安全产生重要影响.基于西藏高原脆弱生态环境和独特生态系统不受破坏、生态系统服务功能与人类生存发展相协调,并对邻近区域环境起到安全保障作用为目的的生态安全进行研究,围绕人类与生态环境之间的相互关系,以生态学、生态经济学和可持续发展原理为指导,采用"3S"技术、野外调查和数理统计相结合的方法,对西藏生态环境问题与成因、经济社会发展对生态环境的影响、生态系统服务功能区域分异,生态承载力与生态风险对生态安全影响等进行了系统调查与评价.通过多学科综合集成,揭示了生态环境脆弱度、人类干扰度和生态安全空间格局,构建了西藏高原生态安全屏障保护与建设体系,为维护西藏高原生态安全和保障区域社会经济可持续发展提供了科学依据.     

青藏高原古岩溶的性质、发育时代和环境特征

青藏高原目前多处所见岩溶地貌主要属第三纪古岩溶之地下部分经后期剥蚀而出露于地表的，风化壳红土和洞穴次生化学沉积等古岩溶相关沉积也多以残留形态出露在已经发生解体的高原主夷平面的南和东南缘，风化壳红土中所含粘粒部分的主要化学成分为SiO2,Al2O3和Fe2O3；粘土矿物多属“伊利石-高岭石”型组合，少数样品属“高岭石-伊利石”型组合，据硅酸系数和粘土矿物组合判断，古岩溶风化壳红土的发育阶段处在化学风化的初期，但由于目前所见红土仅反映当时风化壳剖面根部的化学风化状况，故其较弱的风化指数仍能间接指示古岩溶发育时期湿热的地表环境，扫描电镜观测结果亦表明，风化壳红土中石英砂的表面结构特征以化学溶蚀形成的为主，机械侵蚀形成的为辅，反映了高原风化壳红土垢长期残留特征，对应风化壳发育时期的湿热环境。     

CoLM模型在高原多年冻土区的单点模拟适用性

使用CoLM模型,以青藏高原冰冻圈观测研究站设在唐古拉综合观测场的气象资料作为驱动资料,在青藏高原多年冻土区的唐古拉地区开展了单点模拟试验.通过和该站点同期实测资料对比发现:CoLM模型对高原多年冻土区的辐射通量各分量的模拟效果较好;对潜热通量的模拟误差较大,感热和地表热通量的模拟相对较好;模型能够很好地模拟活动层浅层土壤温度,但随着深度加深,模拟的温度较观测值有所低估.研究表明CoLM模型能较好地模拟多年冻土区地表与大气的能水交换过程,对其进行一些适应性改进后将能得到更好地应用.改进模型的土壤水热参数化过程尤其是添加未冻水参数化方案是将其应用到冻土区首先要解决的问题;再者扩展模型的模拟深度也十分必要.     

夏半年青藏高原“湿池”的水汽分布及水汽输送特征

采用1948-2007年共计60年的NCEP/NCAR再分析资料.计算了夏半年(4-9月)青藏高原大气中的可降水量、水汽输送通量和水汽输送通量散度,分析了夏半年青藏高原可降水量的分布和变化特征,青藏高原及其附近的水汽输送.结果表明:在对流层中层的青藏高原上空,夏季是一个明显的大气水汽含量高中心,"湿池"特征非常显著,湿池主要有三个大的可降水量中心,即高原的西南部、东南部和高原南侧.4-9月,高原上的可降水量变化很大,高原的增湿的速度小于减湿的速度.水汽进人高原主要通过三条水汽通道,即西风带水汽输送通道、印度洋-孟别拉湾水汽通道和南海-孟加托湾水汽通道.水汽主要在高原西南侧、喜马拉雅山中段和高原东南侧进入高原.     

Diatom-based conductivity and water-level inference models from eastern Tibetan (Qinghai-Xizang) Plateau lakes

Climate in central Asia is dominated by the Asian monsoon. The varying impact of the summer monsoon across the Tibetan (Qinghai-Xizang) Plateau provides a strong gradient in precipitation, resulting in lakes of different salinity. Diatoms have been shown to indicate changes in salinity. Thus, transfer functions for diatoms and salinity or related environmental variables represent an excellent tool for paleoclimatic reconstructions in the Tibetan Plateau. Forty freshwater to hypersaline lakes (salinity: 0.1 to 91.7 g l^–1) were investigated in the eastern Tibetan Plateau. The relationship between 120 diatom taxa and conductivity, maximum water depth and major ions were analyzed using an indicator value approach, ordination and taxon response models. Canonical correspondence analysis indicated that conductivity was the most important variable, accounting for 10.8% of the variance in the diatom assemblages. In addition water depth and weathering were influential. Weighted Averaging (WA) and Weighted Averaging Partial Least Square (WA-PLS) regression and calibration models were used to establish diatom-conductivity and water depth transfer functions. An optimal two-component WA-PLS model provided a high jack-knifed coefficient of prediction for conductivity (r² _jack = 0.92), with a moderate root mean squared error of prediction (RMSEP_jack = 0.22), a very low mean bias (0.0003), and a moderate maximum bias (0.26). A WA model with tolerance downweighting resulted in a slightly lower r² _jack (0.89) for water depth, with RMSEP_jack= 0.26, mean bias = –0.0103 and maximum bias = 0.26.     

The property, age and formation environment of the palaeokarst in Qinghai-Xizang Plateau

The karst landforms distributed on the Qinghai-Xizang (Tibet) Plateau can be genetically classed with the Tertiary underground karst, which were gradually exhumed to the surface with the uplift of the plateau during Quaternary period. The relative deposits of the Tertiary palaeokarst processes, such as the residuum and speleothem, were discovered recently in the southern and southeastern fringe areas of the plateau, where has geological-currently been disintegrated by the headward erosion processes of the modern river systems. The major chemical components of the clay portion of the residuum consist mainly of SiO₂, A1₂O₃ and Fe₂O₃. The clay minerals composition of the clay portion belongs to illite-kaolinite pattern for most of the residuum samples, and kaoliniteillite pattern for a few of the samples. It can be judged from the silicic acid index and the clay minerals composition that the formation of the residuum of the Plateau was in its initial phase. However, such a lower chemical weathering index only reflected the weathering degree in the bottom or lower parts of the lateritic weathering crust. The relatively intensive chemical weathering processes of the surface layers of the lateritic weathering crust could be logically speculated. The surface feature textures of quartz grains in the residuum were formed mainly by the chemical erosion, which revealed a long-term humid-tropical environment when the residuum and the palaeokarst formed.     

The property, age and formation environment of the palaeokarst in Qinghai-Xizang Plateau

The karst landforms distributed on the Qinghai-Xizang (Tibet) Plateau can be genetically classed with the Tertiary underground karst, which were gradually exhumed to the surface with the uplift of the plateau during Quaternary period. The relative deposits of the Tertiary palaeokarst processes, such as the residuum and speleothem, were discovered recently in the southern and southeastern fringe areas of the plateau, where has geological-currently been disintegrated by the headward erosion processes of the modern river systems. The major chemical components of the clay portion of the residuum consist mainly of SiO2C, Al2CO3 and Fe2O3. The clay minerals composition of the clay portion belongs to illite-kaolinite pattern for most of the residuum samples, and kaolinite-illite pattern for a few of the samples. It can be judged from the silicic acid index and the clay minerals composition that the formation of the residuum of the Plateau was in its initial phase. However, such a lower chemical weathering index only reflected the weathering degree in the bottom or lower parts of the lateritic weathering crust. The relatively intensive chemical weathering processes of the surface layers of the lateritic weathering crust could be logically speculated. The surface feature textures of quartz grains in the residuum were formed mainly by the chemical erosion, which revealed a long-term humid-tropical environment when the residuum and the palaeokarst formed.     

近34 a青藏高原年降水变化及其分区

 对高原地区34 a（1971—2004年）82站共13 883 d的逐日降水量资料进行了统计,用REOF方法进行了分区,并讨论了趋势变化。青藏高原地区属季风降水区,在东亚季风、印度季风、高原季风和西风带系统的影响下,降水的局部特征显著。近34 a来高原上的降水量整体呈增加趋势,从20世纪70年代到90年代初期降水变化不大,90年代中后期开始明显增加,尤其是近3 a增加明显。青藏高原干旱地区降水完全取决于夏季降水量,并且降水的相对变率大。从青藏高原地区年降水的分区情况来看,西藏及四川的西南部降水增加最明显,每10 a增加幅度为54.5 mm,其次是青海的柴达木盆地和青海湖地区及甘肃的河西走廊地区。而青海的东部及三江源地区,祁连山区,四川的西北部地区呈减少趋势。高原上高海拔地区的降水在减少,而低海拔地区在增加。     

Quaternary geomorphological evolution of the Kunlun Pass area and uplift of the Qinghai-Xizang (Tibet) Plateau

There is a set of Late Cenozoic sediments in the Kunlun Pass area, Tibetan Plateau, China. Paleomagnetic, ESR and TL dating suggest that they date from the Late Pliocene to the Early Pleistocene. Analyses of stratigraphy, sedimentary characteristic, and evolution of the fauna and flora indicate that, from the Pliocene to the early Quaternary (about 5–1.1 Ma BP), there was a relatively warm and humid environment, and a paleolake occurred around the Kunlun Pass. The elevation of the Kunlun Pass area was no more than 1500 m, and only one low topographic divide existed between the Qaidam Basin and the Kunlun Pass Basin. The geomorphic pattern in the Kunlun Pass area was influenced by the Kunlun–Yellow River Tectonic Movement 1.1–0.6 Ma BP. The Wangkun Glaciation (0.7–0.5 Ma) is the maximum Quaternary glaciation in the Pass and in other areas of the Plateau. During the glaciation, the area of the glaciers was 3–5 times larger than that of the present glacier in the Pass area. There was no Xidatan Valley that time. The extreme geomorphic changes in the Kunlun Pass area reflect an abrupt uplift of the Tibet Plateau during the Early and Middle Pleistocene. This uplift of the Plateau has significance on both the Plateau itself and the surrounding area.