荒漠化评价的理论框架

本文在深入调查研究的基础上,参考国内外目前有关荒漠化及荒漠化评价的研究成果,结合我国实际情况,提出了荒漠化评价的理论框架。内容包括荒漠化评价的原则和任务、荒漠化的主要类型和评价类型、荒漠化的气候分区、荒漠化发展程度的判定标准、荒漠化评价的尺度和技术方法等。     

喀斯特石漠化贫困地区文化生态发展研究——以贵州省平坝县桃花村为例

民族在其历史进程中,在不断地适应生存环境时,构建了特有的文化生态,研究特殊环境下民族文化生态的发展,对人类文化生态发展有着重要意义。在对贵州省平坝县桃花村实际调研的基础上,以这一典型民族文化生态村为例,阐述了喀斯特石漠化特殊环境下贫困地区的文化发展特征,并在分析桃花村文化生态发展中存在的困境的基础上,就解决困境提出了一定的对策和建议,以实现喀斯特石漠化贫困地区生态民族的可持续发展。     

近10年共和盆地土地沙漠化时空变化特征分析

以Landsat-TM遥感数据为信息源,依据沙化荒漠化土地分类系统和土地利用类型分类系统，在地理信息系统的支持下，对青海省共和县2001年，2005年以及2011年的TM影像进行了目视解译,分析了该地区近10年来土地沙漠化时空变化规律。分析结果表明,与2001年相比较，2005年沙漠化土地面积减少了71.09km2，年均减少17.77km2,与2005年相比，2011年沙漠化土地总面积减少了49.69km2，年均减少7.1km2。与2001年相比，2011年沙漠化土地总面积减少了120.78km2,年均减少了10.98km2。这表明近年来通过不断的治理与整治，沙漠化趋势在减小，但总体状况还是不容乐观，需要投入更大的治理力度。     

青海省荒漠化治理中林业科技功能研究

青海省随着人口的增加和过渡放牧以及乱砍、乱挖、乱垦造成了生态的严重破坏,使荒漠化面积不断扩大.为了控制荒漠化面积,应充分发挥林业科技功能作用,植树造林、绿化荒漠、减少荒漠化面积.总结了林业科技功能在青海荒漠化治理中的重要作用,并进行了前景展望.     

浅析若尔盖沙化区地形特征

地处青藏高原东隅的若尔盖湿地是长江、黄河上游重要的水源涵养地和长江、黄河流域重要的生态屏障,素有"高原之肾"的美誉。近几十年来该区湿地萎缩、草原沙化严重,直接威胁到该区域及相邻区域的生态环境。通过卫星遥感动态监测显示,沙化地主要分布于黄河两岸河谷地带(首曲、黑河、白河的中游)[1]及其故旧河道,沼泽边缘退化地带以及高山垭口。古河床和河流附近的风积母质上发育的风沙土为沙化区提供了沙源,气温升高、降水减少以及大风因素为沙地的扩展提供了必要的气候条件,而人为的扰动是河谷、沼泽边缘生态脆弱带沙化的诱导因素。     

基于MODIS遥感数据的呼伦贝尔土地荒漠化信息提取

[目的]基于MODIS遥感数据,对呼伦贝尔地区土地荒漠化信息进行提取。[方法]基于空间分辨率为1 km的MODIS遥感数据,选取可以反映不同荒漠化特征的5个指标进行反演,并采用决策树分类方法对呼伦贝尔地区土地荒漠化信息进行提取。[结果]呼伦贝尔地区土地荒漠化面积为33 862 km2,占全区总面积的20.36%,且主要以沙质荒漠化为主;通过野外验证及高分辨率解译数据采点验证,此评价方法总体精度达89%以上。[结论]使用文中评价方法进行荒漠化监测,不仅能够对大尺度的荒漠化地区进行监测,而且具有较好的评价效果。     

寒地落叶松林生态脆弱性分析

大兴安岭林区自开发建设以来,由于没有正确处理好人与自然的关系,导致寒地落叶松林的生境遭到严重的破坏,多年冻土不断退化,寒地落叶松林逐渐北移,致使寒地落叶松林的生态环境极其脆弱。为使寒地落叶松林得到有效保护,文章提出了发展对策。     

我国北方农牧交错地区沙漠化原因及防治措施

分析了我国北方农牧交错地区沙漠化形成的原因，主要有自然因素和人为因素两方面，自然因素有干旱少雨、多风和丰富的沙物质，人为因素有生产活动、耕作经营方式和人口增长等。在此基础上提出了防治措施。     

Nitrogen Fertility Island Stability around Prosopis glandulosa Sprouts after Mechanical Shrub Control in a Degraded Grassland

We examined the effects of mechanical chopping to reduce shrub cover for grassland restoration in a semi-desert environment near Douglas, Arizona, USA. Specifically, soils were sampled to determine spatial and treatment differences, after 10 years, in soil-N fertility islands associated with undisturbed honey mesquite shrubs (Prosopis glandulosa Torr. var. glandulosa) compared with resprouted mesquite shrubs. Honey mesquite is the dominant shrub of this degraded grassland community.

One decade after mechanical crushing of shrubs for grassland restoration, soil amino sugar nitrogen (N) values and patterns for resprouted honey mesquite and undisturbed shrubs did not differ from one another according to a repeated measures analysis of variance. However, the concentrations in samples of the surficial 30-cm of soil around undisturbed and resprouted shrubs combined differed statistically at 161 parts per million (ppm) at trunk, 100 ppm midway between trunk and dripline, 78 ppm at the dripline, and 46 ppm beyond the dripline.

The results indicate that soil N fertility remained stable, but with decreasing levels at regular, radial sample points extending from the trunk to beyond the dripline, around mesquite shrubs that resprouted 10 years after mechanical crushing of tops for grassland restoration.     

Processes and mechanisms of desertification in northern China during the last 30 years,with a special reference to the Hunshandake Sandy Land,eastern Inner Mongolia

Desertification has been widely recognized as one of the most serious environmental problems in China, although its concept and causes are still debated in scientific communities. The semi-arid region in northeastern China, located on northern margin of eastern Asian summer monsoon, is ideal for investigating the processes and mechanisms of desertification because of its very sensitive ecosystem. Using the Hunshandake Sandy Land of eastern Inner Mongolia, a former dormant dunes and wetlands environment, we monitored the variation of the desertified land and the wetlands in order to assess the climatic and human impacts on the processes of desertification. The research methods included digital image processing of LANDSAT data and ground checks. The remote sensing data from the last three decades show that the wetlands were larger in 1975 and 1992 than in 1989 and 2001. The variation of the extension of mobile dunes is in inverse proportion to that of wetlands. The main process of desertification is the reactivation of dormant sand dunes. The changes of wetlands and desertified lands correlate considerably well with the variations of local precipitation and temperature, suggesting that climate might be the key factor triggering desertification in the Hunshandake. In other sandy lands of China, however, human activities might be the key factor causing desertification and land degradation.