Land degradation in the source region of the Yellow River, northeast Qinghai-Xizang Plateau: classification and evaluation

Land degradation imposes a great threat to the world. It is not merely an environmental issue, but also a social and economic problem. Land desertification is among the main aspects of environment changes in the source region of the Yellow River. Previous studies focused on water resource utilization and soil erosion, but land degradation in the source region of the Yellow River even the whole Qinghai-Xizang Plateau received little attention. Based on the data obtained by field investigation and TM satellite images of 2000, this study provides the classification and evaluation information of the land degradation in the source region of the Yellow River. There are six types of land degradation in this region: water erosion in the northern mountains around the Gonghe Basin, sandy desertification in the Gonghe Basin and Upland Plain Area, aridization in the lower reaches, salinization in the Gonghe Basin, vegetation degradation in the intramontance basin and freezing and thawing erosion in the high mountains. The total degraded area is 34,429.6 km², making up 37.5% of the land in the study area. Finally, land degradation in the source region of the Yellow River was evaluated according to changes in the physical structure and chemical component of soils, land productivity, secondary soil salt and water conditions.     

Natural and anthropogenic hazards in the Yellow River Delta,China

Natural Hazards - In China, the Yellow River Delta is a unique region with vulnerable ecosystems, and it is under the largest pressure from various risk sources. In recent years, this region has...     

黄河源区生态环境退化研究

生态环境退化是黄河源区所面临的重要的生态问题和社会经济问题。源区生态环境退化不但影响本区经济的可持续发展,而且对中下游地区的生态环境和水文条件构成很大威胁。在收集区内现有研究成果的基础上,通过对2000年TM影像的解译,对黄河源区生态环境退化现状和特征作了全面系统的研究。源区生态环境退化主要表现在冰川退缩、冻土面积的减小和冻融侵蚀面积的扩大,植被退化和土地退化的加剧等过程。最后,在分析未来气候变化和人类活动的基础上,对生态环境变化趋势作了预测。     

Environmental hazards from population pressure in the Jinta Oasis, arid northwestern China

Oasis is not only the most concentrated area of human activities in arid region but also the largest area where artificial disturbances occur at the regional scale. The Jinta Oasis is a very typical artificial oasis in arid region of China and is set as one of the national land resource developing and representative areas in China. With the continuous increase in population and livestock number in Jinta Oasis, such severe problems of environmental degradation as serious land pollution and desertification, water environmental degradation, and vegetation degeneracy occur within the whole oasis.     

黑河流域环境退化特征分析及防治研究

生态环境条件的好坏,是制约我国社会、经济和人民生活可持续发展的重要问题之一,特别是在生态环境脆弱的西北干旱区的内陆河流域。本文以黑河流域为例,根据最新的野外调查数据,结合该流域已有的研究文献资料,分析了黑河流域生态环境退化的现状和主要特征。研究结果表明,黑河流域生态环境退化主要是由于人类不合理的经济活动造成的,具体表现在土地的沙漠化、水资源的变化、土壤盐渍化和植被退化等方面。在此基础上,初步提出了防止流域生态环境恶化的综合治理对策。     

Impacts of coal mining subsidence on the surface landscape in Longkou city,Shandong Province of China

Coal mining subsidence is a common human geological disaster that was particularly conspicuous in China. It seriously restricts the sustainable development of mining areas, and it not only damages land resources but also triggers a series of ecological and environmental problems that may result in social and economic issues. This report studied the coal mining subsidence area of Longkou in Shandong province and uses digital elevation data (DEM) of the mining area before subsidence in 1978 as the baseline elevation. Through image algorithms, we obtained coal mining subsidence region data for 1984, 1996, 2000, and 2004. And with spatial data sources of the same period of TM/ETM⁺ and SPOT5 remote sensing images, BP artificial neural network (BPNN) classification is used to extract surface landscape information in the subsidence area. With the support of GIS technology, superimposing subsidence area on the surface landscape—using the largest landscape ecology patch index, landscape shape index, landscape condensation index, and the index of landscape distribution—report analyzes the mining landscape changes before and after subsidence. This study also carries on exploratory research with the landscape changes, thereby providing a scientific basis for integrated prevention and treatment.     

Wetland loss and degradation in the Yellow River Delta, Shandong Province of China

Environmental degradation of wetlands is a major issue in the Yellow River Delta of China. Natural threats and human activities, such as flow cut-off of the Yellow River and droughts, population growth and urbanization, cause wetlands degradation of the delta during the last century, especially in the recent 50?years. Wetland degradation in the Yellow River Delta was investigated and its causation was analyzed. The results indicated that landscape changes of wetlands were mostly tremendous in the whole delta, namely loss of wetland area, surface water and groundwater pollution. Some new degradation control measures based on traditional and scientific knowledge must be used to reverse the wetlands degradation in the Yellow River Delta.     

Karst landslides hazard during 1940–2002 in the mountainous region of Guizhou Province, Southwest China

Mountain landslide has been an environmental geological problem and occurs frequently in China, especially in the karst region of Guizhou Province, Southwest China. The data of karst mountain landslide are collected and analysed, which occurred in the period of 1940–2002. The collection includes 321 events in the karst region of Guizhou Province. The characteristics of mountain landslides may be classified as two types, namely natural mountain landslides (287 events) and the other induced by human activities (34 events). The results indicate that natural mountain landslide causes especially high damage and is still the main type of natural hazard in the study area owing to the extremely fragile karst geological environment.