阜新重点沙化地区沙化动态变化研究

<正>阜新市彰武县处于科尔沁沙漠南缘,是辽宁受风沙、干旱危害最严重的地区,沙化导致生态平衡遭到破坏,自然环境趋于恶化,生物多样性受损,降低了区域可持续发展的能力。因此,对阜新市重点沙化地区进行监测具有重要意义。研究意义传统的沙化监测是在已往沙化调查监测数据的基础上,进行人工野外实地调查与勾绘,更新沙化图     

雅鲁藏布江中部流域土地沙化遥感识别

雅鲁藏布江中部流域长期遭受土地沙化侵蚀,采取有效手段进行沙化土地信息快速识别,跟踪土地沙化现状和动态发展,是土地沙化防治的基本前提。遥感数据因其快速、大范围、高精度监测等特点已被广泛应用于土地沙化监测。为降低该区域沙化土地破碎化分布特征以及广泛分布的稀疏植被地表对沙化土地遥感识别带来的不确定性,本文利用Google Earth Engine平台获取2019年秋季雅鲁藏布江中部流域Landsat无云遥感影像,基于面向对象的分类思想,充分提取沙化土地的光谱、几何和地形特征,根据不同的分类器构建4种分类方案,包括单一分类器（支持向量机、决策树、最近邻）分类以及组合分类法分类,提取雅江中游河谷地区沙化土地信息并验证不同方案的提取精度。结果表明：① 利用面向对象组合分类模型提取的沙化土地信息效果最佳,总体精度高达91.38 %,Kappa系数为0.82;② 相较于采用单一分类器（支持向量机、最近邻和决策树分类）的面向对象分类方法,组合分类模型能更有效地识别破碎化的小面积沙化土地,降低沙化土地与稀疏植被地表的混淆情况,提高分类可靠性;③ 基于面向对象组合分类模型反演得到雅鲁藏布江中部流域2019年沙化土地分布信息,土地沙化面积达299.61 km²,总体上呈现沿河谷的带状不连续分布,且集中分布于河流北岸以及靠近河道的阳坡、低海拔地区。本研究可为土地沙化遥感监测提供新思路,其应用可服务于雅鲁藏布江中部流域土地沙化预防和治理工作。     

辽宁投3亿元治理 300万亩沙化草原

辽宁省近日决定投资3亿元,在沙化严重的阜新、彰武、建平、北票、朝阳、凌源等10个县（市）治理沙化草原300万亩。     

陕西治理沙化土地897万亩

日前,国家林业局通报了“十一五”省级政府防沙治沙目标责任综合考核结果,陕西被确定为工作突出省份。据悉,“十一五”期间,陕西通过三北防护林建设等林业生态项目,共完成沙化土地治理任务897万亩,达目标任务870万亩的103％;荒漠化和沙化土地面积分别缩减61万亩和32万亩,重度、     

对泰来县地质环境保护与综合治理项目实施管理的思考

泰来县位于黑龙江省西南部,地处黑龙江、吉林、内蒙古三省（区）交界处,幅员总面积3960平方公里,沙化土地面积150万亩,是国家级贫困县,也是国家级防沙治沙重点县。由于地质环境遭到严重破坏,出现了严重的盐碱化、沙化、草原退化等地质灾害。为了改善生态环境、恢复草原植被、提高土地利用率,泰来县申请专项资金1008万元,先后在8个乡镇（场）,     

中国北方农牧交错带土地沙化区典型植物的雨季水分来源

中国北方农牧交错带是中东部地区重要的生态安全屏障, 由于其系统结构脆弱、生态环境问题多发、土地沙化严重, 开展生态修复工作显得十分重要。植物-土壤水分关系作为土地沙化区生态水文过程的重要组成部分, 研究二者的转化过程对于了解植物吸水模式、确定生态修复的首选植物种非常关键。以河北省张家口市康保县北部为例, 基于雨季的大气降水、地下水、土壤水和植物水的氢氧同位素特征, 分析了主要植物的吸水层位、生态位宽度和水分竞争关系。结果表明, 柠条以吸收80~100 cm深度土壤水为主, 吸水比例最大可达87.7%, 油菜花以吸收0~20 cm深度土壤水为主, 吸水比例最大可达82.3%, 狼针的吸水层位与土壤含水率有关, 在含水率较高的深度吸水比例更大, 栉叶蒿的吸水深度较为均衡, 各植物种的生态位宽度均较大, 但部分植物间存在较强的水分竞争关系。本研究为中国北方农牧交错带土地沙化区的植物水源来源识别和生态修复提供了科学依据。      

知识天地

荒漠化是指在不利的自然条件和（或）人为不合理开发利用土地的条件下,土地发生沙化、石质化,以及土壤发生盐渍化、贫瘠化、污染等的总称。     

内蒙古中部MODIS植被动态监测分析

对中分辨率成像光谱仪(MODIS)250m空间分辨率的每8天NDVI卫星遥感数据,利用年平均NDVI及一元线性回归方法,分析了2000-2008年内蒙古中部地区植被变化趋势。结果表明,近9年内蒙古中部地区79.60%地区的植被总体上保持稳定,17.33%的地区得到了明显改善,3.06%的地区仍存在较强的退化或沙化趋势。退化或沙化地区主要分布在内蒙古农牧交错带北部边缘,成条带状分布,反映了农牧交错带地区生态仍然较为脆弱,需要进一步关注和保护,东南部地区的植被恢复明显。植被年际动态主要受该地区暖干化气候影响,气候变暖造成植被NDVI增加,而降水波动导致NDVI随之变化,降水的作用是气温的2.8倍,有些地区可达到11倍之多。     

中国千亿巨资投向退耕还林

国家林业局近日宣布，中国土地荒漠化和沙化情况出现了自1999年来的双逆转，各占国土面积的27．46％和18．12％，生态建设状况己由“治理小于破坏阶段”进入了“治理与破坏相持阶段”。     

吉尔嘎郎图草原栗钙土沉积微相研究

锡林郭勒大草原的迅速沙化,已经成为我国严重的环境问题。查清其第四系沙源的沉积相和微相及其空间特征,有 助于寻找标本兼治的途径与方法。以锡林河中游的吉尔嘎郎图平地小草原为例,首 先,对典型剖面进行了分层精准观测和采样测试,把宏观沉积学研究与微观粒度参数分析相结合,在第四系栗钙土中识别出河床、堤岸和洪泛３个亚相及其所属的６个微相,建立了６种微相的粒度分布模型;然后,基于图解法的粒度参数计算和有约束点的动态聚类分析法,实现了面上大量栗钙土样品的沉积微相归类,从而快速有效地查明了沙化沙源为河流侵蚀成因,沙源来自下伏白垩系顶部的古河流－三角洲砂体。      

Thermohaline structure inhomogeneity associated with polynia at the northern margin of Emery Ice-shelf

Based on the hydrographic data in austral summer during the 22nd Antarctic Expedition of China(2005/2006),some features can be found about the northern margin of Emery ice shelf as follows.The heat content in the surface layer(0-50 m) at the eastern end and the western end of the ice-shelf margin is much higher than that at the middle.The upper mixing-layer depth and the seasonal thermocline depth at the middle of the ice-shelf northern margin are much shallower than those at the both ends.However there is much less difference between the middle and the ends in the bottom layer.The remote sensing photos show that the inhomogeneity in the surface-layer water is closely related to the spatial distribution of the floes and polynia in the area.     

Phylogenetic analysis of cultivable bacteria isolated from Arctic sea-ice

Phylogenetic analysis based on 16S rDNA of 8 strains of cultivable bacteria isolated from Arctic sea-ice was studied.The results showed that strain BJ1 belonged to genus Planococcus,which was a genus of low mole percent G C gram-positive bacteria;strain BJ6 belonged to genus Burkholderia of β-proteobacteria and the rest 6 strain all belonged to γ-proteobacteria,of which strain BJ8 was a species of Pseudoalteromonas,strain BJ2-BJ5 and BJ7 were members of genus Psychrobacter.Phylogenetic analysis also indicated that bacteria of genus Psychrobacter of the isolates formed a relatively independent phylogenetic cluster in comparison with other bacteria belonged to genus Psychrobacter.     

Information for authors

正1 Aims and Scope Advances in Polar Science(APS)is an international,peer-reviewed journal jointly sponsored by the Polar Research Institute of China and the Chinese Arctic and Antarctic Administration.APS is a comprchensive academic journal dedicated to presentation of multi-disciplinary achievements in Arctic and Antarctic expeditions and research.Its primary purpose is to publish achievements in fundamental research,applied     

Advances in Polar Science CONTENTS(Volume 25,2014)

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Guide to Authors： Journal of Mountain Science

<正>AIMS AND SCOPE(Editorial Policy)The Journal of Mountain Science(JMS)is devoted to mountains and their surrounding lowlands-ecoregions of particular global importance,with a particular emphasis on the important highlands/mountains in the world,such as the Tibetan Plateau,the Himalayas,the Alps,the Andes,the Rockies and many other mountain ranges of our planet.     

Journal of Mountain Science(JMS)

<正>The Journal of Mountain Science(JMS),founded in2004,is an international English-language journal on mountain sciences.JMS is supervised by the Chinese Academy of Sciences(CAS),sponsored by the Chengdu Institute of Mountain Hazards and Environment,CAS,published by Science Press China,and distributed by Springer exclusively throughout the world(excluding Mainland China).The JMS is published bimonthly,fulltexted in SpringerLink and CNKI,indexed/abstracted by     

Influence of livestock soil eutrophication on floral composition in the Pyrenees mountains

Livestock behaviour in the Pyrenees includes free grazing and a long resting period that provokes the accumulation of dung and urine in some places,so-called camping areas. The aims of this study were （i） to analyze any change in floral composition,and in nutritional and chemical contents of plants in a livestock camping area; and （ii） to relate the floral composition with soil chemical properties. In a linear transect,five sampling zones were established,from the centre of the camping area to the surrounding Nardus stricta-dominant pasture. The above ground plant biomass and the topsoil were sampled in each zone with 6 replicates per zone. Plant species were classified and weighed to calculate above ground biomass,nutritional and chemical contents,and Shannon diversity and evenness indices. Additionally,soils were sampled in two periods,at the beginning and at the end of grazing period. Soil available nutrients （nitrate,ammonium,phosphorus,potassium,calcium and magnesium）,total nitrogen,organic carbon and pH were measured.
Plant chemical contents （protein,lignin and others） were significantly related to the proportions of grasses,legumes and other plants; so,the protein content is positively correlated with legumes plant biomass while lignin content is negatively correlated with grasses. Both plant and soil nutrients increased linearly towards the centre of the camping area. However,the relationship among plant species richness,diversity and evenness relative to its position along the studied transect was bell-shaped. From the outskirts to the centre of the camping area,plants with low nutrient demand were progressively replaced by those with medium and high nutrients demand and by pioneers.
Nardus stricta-dominant pasture has low plant diversity and plant nutrient content as well as a poor soil nutrient availability. The presence of the camping area introduced patches with more soil nutrients and new species in the large spatial scale. However at a small spatial scale,the strong soil nutrien     

General Table of Contents(Vol.11,2014)

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介绍GPS定位中的几个概念

文章概略介绍了利用卫星进行定位的原理 ;由卫星信号传播、信号接收和SA政策等引起的理论误差 ;给出了多种快速、高精度定位的工作模式和观测点选择的原则 ;列出了将WGS - 84坐标转换为我国坐标的公式及解算参数的具体方法 ,供读者在GPS工作中参考。