The causes and processes responsible for rocky desertification in karst areas of southern China

The karst region of southern China is a fragile ecological zone with widespread rocky desertification. This paper describes the rocky desertification occurring in this region in terms of both natural and anthropogenic factors. During geological time periods, the region’s changing environment governed the natural rocky desertification processes, whereas during historical and modern times, anthropogenic processes have been superimposed on these natural processes. Human activities have accelerated and exacerbated rocky desertification. The period from the beginning to the middle of the Qing dynasty was an important transitional period in which human activities began to exert a particularly strong influence on rocky desertification. Since then, the effect of anthropogenic factors has increasingly exceeded the effect of natural factors. The rocky desertification process in southern China’s karst region combines surface ecological processes (including vegetation degradation and loss, soil erosion, surface water loss, and bedrock solution) with a reduction of the land’s biological productivity, leading to degradation that produces rocky desert. Controlling rocky desertification requires comprehensive development of sustainable agriculture and economic development that provides employment alternatives to agriculture and thereby promotes the rehabilitation of rocky desertified land.     

中国沙区人居环境安全研究的初步探讨

沙漠化严重威胁沙区人居环境安全,研究沙区人居环境安全保障技术,是关系到民族生存空间的迫切任务。基于人居环境理论的介绍,阐述了沙区人居环境的概念、内涵、分级和研究尺度,初步勾勒了沙区人居环境安全研究的内容体系和评价方法。在深入讨论导致沙区人居环境恶化根源的基础上,认为从资源环境和人类社会两个互相耦合的维度上,从沙区人居环境这一综合的系统整体入手,是防沙治沙技术研究重大突破的一个方向。     

云南石林景区恢复植被的土壤水文结构功能研究

基于喀斯特恢复植被生态系统功能评价的要求,采用土壤水文结构功能模型评价云南石林景区恢复植被的土壤水文结构功能。选取原生滇青冈林、恢复26a的次生林B、恢复21a次生林A、恢复8a的灌丛、石漠化灌草丛和恢复30a云南松林6个样地,分别调查它们的土壤水文结构特征。相对于原生林,石漠化样地经过8a的封禁,其土壤水文结构功能可恢复31%,21a可恢复45%,人工飞播的云南松林经过30a恢复的只有38%,而砍伐林地封禁26a可恢复71%。土壤水文结构功能评价模型基本适用于岩溶区不同恢复林地的土壤水文结构功能的恢复评价。      

我国西南岩溶石漠化土地生态建设分区治理思路与途径探讨

论述了实施岩溶石漠化分区治理的必要性;根据岩溶石漠化土地分布特点及区域自然地理、社会经济、生物资源等差异性,将我国西南岩溶区分为中高山、岩溶断陷盆地、岩溶高原、岩溶峡谷、峰丛洼地、岩溶槽谷、峰林平原及溶丘洼地（槽谷）8个岩溶石漠化综合治理区,其建设重点与主要措施分别是:中高山区重点实施封山育林育草与营造生态防护林与薪炭林,利用自然景观和原生态文化,发展生态旅游业;岩溶断陷盆地区对盆地周边山地实施封山育林育草,盆地内修缮水利设施,建设高效经果林或中草药基地;岩溶高原区保护好现有林草植被,积极发展水源涵养林与经济林,完善生态体系结构,培育生态经济型产业,合理开展生态移民;岩溶峡谷区通过封造、乔灌治理相结合,提高岩溶植被的生态功能,积极发展生态旅游业与特色农林牧业;峰丛洼地区开展封山育林育草,发展南亚热带特色林业,适度进行生态移民;岩溶槽谷区加强对石漠化区域的生态建设,提高非石漠化土地的开发利用力度;峰林平原区合理开发利用地表和地下水资源,实施封山育林和人工造林,提高森林生态功能与景观价值;溶丘洼地（槽谷）区则围绕洞庭湖流域、岩溶景观区开展封山育林育草、人工造林,加强薪炭林与沼气池建设。      

江苏兴化DS浅孔沉积物地球化学元素与粒度所揭示的古环境意义

选择位于东亚季风典型区的苏北盆地沉降中心附近湖沼沉积为研究对象,进行了AMS¹⁴C、粒度、地球化学元素的综合分析。分析表明,末次冰消期以来苏北盆地古气候经历了冷干、暖湿、温湿、冷暖波动剧烈、暖湿的变化过程。苏北盆地DS钻孔沉积物所揭示的气候变化与贵州董歌洞石笋氧同位素数据和格陵兰冰芯数据所揭示的气候变化总体变化趋势大体一致,但在一些细部上还是存在着差异,较好的响应了区域环境和全球气候变化。     

基于元胞自动机民勤绿洲湖区荒漠化演化预测

民勤湖区是民勤绿洲中生态环境最为恶劣的地区,土地荒漠化问题十分突出。以民勤绿洲湖区为例,解译1992年、1998年、2002年和2006年TM卫星影像,分析其荒漠化动态变化情况,利用ArcObjects模块结合地理元胞自动机理论构造荒漠化动态模拟模型,通过对比2006年的预测数据与实际数据,对模型进行参数调整和预测检验。预测结果表明,模型预测的准确性达到90%。最后对2012年该区土地利用状况做出预测,进而对荒漠化的发展趋势进行预测分析。     

西部中国沙棘叶片稳定碳同位素组成的空间特征及其气候意义

分析了西部中国沙棘（Hippophate rhamnoides sinensis）叶片稳定碳同位素组成特征及其与环境因子之间的关系。结果表明,中国沙棘叶片δ13C值在-30.40‰~-24.91‰之间变化,平均值约为-27.62‰,属于C3植物。随纬度和经度的升高,中国沙棘叶片δ13C值明显升高,而随海拔的升高而降低,具有明显的空间分布特征。中国沙棘叶片δ13C值与温度没有明显的关系,随蒸发量和日照时间的升高而升高,随降水量的升高有降低趋势,具有明显的气候意义。表明中国沙棘具有较高的水分利用效率,水分是控制中国沙棘δ13C值变化或生长的主导因子。     

沙漠化地区的旅游发展对沙漠化的影响研究——以河西走廊为例

以河西走廊为例研究了沙漠化地区的旅游开发对沙漠化的影响。研究发现,河西走廊主要的旅游资源的开发,都受到了沙漠生态环境空间上的制约,因此多数的旅游产品都集中在生态环境较好的绿洲上。通过计算旅游人口的用水量发现,旅游发展对沙漠化的直接影响很小,但旅游业在沙漠化地区不同流域地段的发展会对政府的环境政策产生不同的影响,从而间接影响到沙漠化的进程。     

南极政治及浅析

随着各国对南极考察和研究的日益深入,南极政治作为国际政治的一个新兴领域已经形成。本文拟通过对南极地区的领土争端问题、环境保护问题、矿产资源问题和科学考察问题的研究来阐述南极政治的主要内涵,并对南极政治法律框架在解决这些问题中的作用进行初步的分析,探讨南极条约体系与国际社会的互动对南极政治的影响。     

Cropland cover change in Northeast China during the past 300 years

Land use/cover change induced by human activities has emerged as a “global” phenomenon with Earth system consequences. Northeast China is an area where the largest land cultivation activities by migrants have happened in China during the past 300 years. In this paper, methods including documentary data calibration and multi-sourced data conversion model are used to reconstruct historical cropland cover change in Northeast China during the past 300 years. It is concluded that human beings have remarkably changed the natural landscape of the region by land cultivation in the past 300 years. Cropland area has increased almost exponentially during the past 300 years, especially during the past 100 years when the ratio of cropland cover changed from 10% to 20%. Until the middle of the 19th century, the agricultural area was still mainly restricted in Liaoning Province. From the late 19th century to the early 20th century, dramatic changes took place when the northern boundary of cultivation had extended to the middle of Heilongjiang Province. During the 20th century, three agricultural regions with high ratio of cropland cover were formed after the two phases of spatial expansion of cropland area in 1900s–1930s and 1950s–1980s. Since 1930s–1940s, the expansion of new cultivated area have invaded the forest lands especially in Jilin and Heilongjiang Provinces. Supported by National Natural Science Foundation of China (Grant No. 40571165) and Innovation Foundation of Chinese Academy of Sciences (Grant No. KZCX2-YW-315)