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1.
The causes and processes responsible for rocky desertification in karst areas of southern China 总被引：2，自引：0，他引：2
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. 相似文献
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中国沙漠化研究进展 总被引：4，自引：0，他引：4
王涛 《地理学报(英文版)》2004,14(4):387-400
Sandy desertification is land degradation characterized by wind erosion mainly resulted from the excessive human activities in arid, semiarid and part of sub-humid regions in northern China. The research on sandy desertification has experienced more than 5 decades of arduous course of the struggle along with the establishment and development of China‘s desert science. Researches in this field have made a great contribution to the national economic construction, and environmental protection. This paper focuses on presenting the major progress and achievements in the sandy desertification research during the last 50 years, including the stages of study on sandy desertification,background environment of sandy desertification and its changes, the conception, causes, process,monitoring and assessment of sandy desertification, the vegetation succession, landscape ecology, plant physiology, impacts on ecosystem, high-effective use of water and land resources and sustainable development in sandy desertified regions, sandy desertification control models and techniques etc. 相似文献
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The area of desertified land has increased by 27.3% from 1987 to 2000 in Maduo County,northeastern Qinghai-Tibet Plateau.Driving forces of land degradation has been extensively studied in the region.Using Factor Analysis (FA),we evaluate contribution of human activity and natural environmental change to land degradation.Four common factors were extracted in this study.The result shows that climate related other than human-related factors,are the major inducing factors of land degradation in Maduo County.Climate change and consequent change of permafrost account for 70% to the land degradation.Increasing evaporation and declining precipitation in the beginning of the growing season hamper seedling establishment.Decreasing frozen days and rising active layer lower bound make surface soil loose and less soil moisture available for plant. 相似文献
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Sandy desertification in the Shule River Basin has expanded dramatically during the past 30 years. We evaluated the status, evolution, and main causes of sandy desertification by interpreting Landsat images which were acquired in 1978, 1990, 2000, 2005, and 2010, and analyzing the relevant meteorological data. The results show there was 3,477.95 km2, 3,733.32 km2, 3,620.29 km2, 3,565.65 km2, and 3,557.88 km2 of sandy desertified land in 1978, 1990, 2000, 2005, and 2010, respectively. From 1978 to 1990, not only the area of sandy desertified land （SDL） but also the degree of SDL levels increased. From 1990 to 2010 there was widespread restoration of SDL but the recovery trend of SDL gradually slowed. Although climate change contributes to expanding sandy desertification, human activities can either accelerate or reverse trends of natural sandy desertification. Some detrimental human activities can accelerate sandy desertification, but, conversely, desertification control measures such as the Three-North Shelter Forest Project and watershed rehabilitation programs in areas including the Shule River Basin resulted in many SDL being turned into grasslands or forest lands when shrubs and trees were planted to fix mobile sands at the edges of oases and cities. With population growth, much SDL has been reclaimed as farm land using water-saving agricultural methods or has been turned into built-up land as a result of urbanization. 相似文献
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The west sandy land of the Northeast China Plain is located in the eastern huge sandy belt of mid-latitude in Eurasia and the eastern fringe of desertified land with best bio-climatic conditions in China. Over-extensive regional development has made the desertified landscape very obvious, especially in Horqin Sandy Land where desertification is more serious than that in Hushandake Sandy Land with worse bio-climatic conditions. There were some researches on the desertification in western No… 相似文献
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The area of land that is affected by soil erosion in the Yangtze River has been reduced by 146,000 km2(accounting for 27% of the entire Yangtze River) since 2000. However, the contributions of different tributaries to this soil erosion decline and the underlying causes have not been determined. Here we quantify the soil erosion decline in the Yangtze River and the impacts of the Grain-for-Green Programme(GFGP) and climate change using the RUSLE model and statistical methods. The resul... 相似文献
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长江上游社会经济因子对侵蚀产沙的影响 总被引：1，自引：0，他引：1
In recent years,the role of human activities in changing sediment yield has become more apparent for the construction of hydraulic engineering and water conservation projec-tions in the Upper Yangtze River,but it has not been evaluated at the macro scale.Taking Sichuan Province and Chongqing City as an example,this paper studies the relationship between socio-economic factors and sediment yield in the Upper Yangtze River based on section data in 1989 and 2007.The results show that sediment yield is significantly correlated with population density and cultivated area,in which the former appears to be more closely related to sediment yield.Moreover,in the relation of sediment yield vs.population density,a critical value of population density exists,below which the sediment yield increases with the increase of population density and over which the sediment yield increases with the decrease of population density.The phenomenon essentially reflects the influence of natural factors,such as topography,precipitation and soil property,and some human activities on sediment yield.The region with a higher population density than critical value is located in the east of the study area and is characterized by plains,hills and low mountains,whereas the opposite is located in the west and characterized by middle and high mountains.In the eastern region,more people live on the lands with a low slope where regional soil erosion is slight;therefore,sediment yield is negatively related with population density.In contrast,in the western region,the population tends to aggregate in the areas with abundant soil and water resources which usually lead to a higher intensity of natural erosion,and in turn,high-intensity agricultural practices in these areas may further strengthen local soil erosion.It is also found that popu-lation tends to move from the areas with bad environment and high sediment yield to the areas with more comfortable environment and less sediment yield.The natural factors have greater influence on sediment yield of western region than that of eastern region.Generally,the natural factors play a dominant role on sediment yield in the Upper Yangtze River. 相似文献
8.
Human Causes of Aeolian Desertification in Northern China 总被引：1，自引：0，他引：1
Tao Wang Xian Xue Yiqi Luo Xuhui Zhou Bao Yang Wanqun T Wei Wu Lihua Zhou Qingwei Sun XunmingWang Halin Zhao Xueyong Zhao 《寒旱区科学》2008,(1):0001-0013
Aeolian desertification has rapidly developed in the past 50 years in Northern China,covered an area of 0.386 million km2 by 2000,affected nearly 170 million population,and caused the direct and indirect economic loss of about $6.75(U.S.dollar) billion per year.Here we present several lines of evidence to demonstrate that human activities guided by policy shifts have been a major force to drive aeolian desertification via changes in land-use patterns and intensity.It is suggested that the desertification can be curbed or even reversed by adopting prevention and control measures with ecologically sound land-use practices in China. 相似文献
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Lakes in China have undergone considerable environmental changes during the past 50 years, e.g. lake level, water area changes, as did in the past several thousands years. The enhanced human activities, such as land reclamation, application of chemical fertilizer, land use and cover, irrigation and industrialization in the catchment etc., have played an important role on the recent decades＇ changes of these lakes, although constrained to a great extent by the natural impact. Comparative study on variations of lake volume （water level, depth and area） in the eastern and western lake regions of China during 1950-2000 indicated that, lake volume in the eastern region had approximately undergone a two-stage change, i.e. a dramatic decrease from the 1950s to 1970s, and a continuous increase between the 1980s and 1990s; while, in the western region, lake volume had been decreasing nearly all the time. Further studies on some typical lakes concluded that, climatic change was a primary factor for the variations of lake volume during the past 50 years, although human activities showed important effect. 相似文献
10.
Impact of farmer households’ livelihood assets on their options of economic compensation patterns for cultivated land protection简 总被引：4，自引：1，他引：3
With rapid urbanization and the socio-economic transformation, cultivated land protection has gradually become a major concern in China. The economic compensation plays a crucial role in promoting cultivated land protection and improving the utilization ratio of cultivated land. Farmer household＇s satisfaction has a great influence on the effectiveness of compensation. Therefore, households＇ willingness to select the economic compensation pattern for cultivated land protection has been considered and re-examined. By employing Participatory Rural Appraisal method （PRA）, 3 villages and 392 households were investigated and sampled in mesa and hilly areas of Chongqing. Then a quantitative analysis framework of household livelihood hexagon has been developed to quantify the livelihood assets of differ- ent farmer households. Finally, the Gray Relation Model and Probit Regression Model have been employed to explore the coupling relationship between the household livelihood assets and their compensation pattern options. The results show that there are both qualitative and spatial heterogeneity in household livelihood assets. We found that the inequality of livelihood assets is evident for five household types. There is a spatial trend that the higher the eleva- tion, the less livelihood assets are. In addition, their options of economic compensation pat- tern vary from Chengdu Pattern to Foshan Pattern due to their difference in livelihood assets and difference in location. In detail, there is a coupling relationship between household live- lihood assets and their compensation pattern; negative correlation is observed between natural assets value and household pattern options, while the other livelihood assets have positive impacts on compensation pattern in varying degrees, which from the top are psy- chological assets, human assets, physical assets, financial assets, and social assets respec- tively. A conceptual compensation pattern system has been designed to meet the demands for farmer households mainly according to their shortage in livelihood assets. In addition, compensation method, compensation standard, the basis of compensation and the source of compensation funds have been proposed accordingly. 相似文献
11.
The sandy land of the western part of Jilin Province is located in the ecotone of semi-humid and semi-arid area in the temperate zone of China. The sandy desertification has widely spread in the region because of the vulnerable natural conditions and the unreasonable human activity; as a result of this, the precious land resources and the economic development in the area have been seriously impacted. In this paper, the sandy land ecologic environment geographic information system is established based on the multi-spectral, multi-temporal Landsat TM images and field investigation. The comprehensive indexes of sandy desertification extent assessment which include vegetation degradation, wind erosion extent and soil depth are presented to classify the sandy land in western Jilin into three levels--slight, moderate and severe sandy desertification with the support of GIS platform. The results demonstrate that the sandy desertification has been partly controlled in the past twenty years, except some small sites. However, this doesn't necessarily mean that there is nothing for more concern. The two main causes of sandy desertification have not been eliminated yet, one is its natural factor, especially the physical and chemical characters of sandy soil and dry climate; another is the immoderate economic activity of human being that has highly accelerated the sandy desertification process. 相似文献
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科尔沁地区现代沙漠化过程的驱动因素分析 总被引：64，自引：36，他引：28
基于近50a科尔沁地区沙漠化土地发展-再发展-逆转的时空变化的研究结果, 以气候波动和人类活动变化作为主驱动因子, 探讨现代沙漠化过程的驱动因素的作用。近40多年气候的波动在一定程度上直接地通过不同时期的降水-温度组合影响着沙漠化的进程, 间接地通过人类对气候波动的响应而产生的经济活动来加速沙漠化的进程。尽管科尔沁地区的气候驱动因子呈现出有利于沙漠化发展过程的趋势, 但在近10多年来, 这种驱动力的作用被有利于沙漠化逆转过程的驱动力所抵消。人类活动是研究区沙漠化过程中更加活跃的驱动因子, 体现在土地利用方式的转变和强度的增加, 以及由此而产生的对自然植被群落毁灭性的破坏而加速了沙漠化的进程。以土壤风蚀为例, 这种加速可以是自然条件下的4~10倍; 随着沙漠化程度的加剧, 所产生的在土壤养分、生物多样性和生物生产量等方面退化的加速也与自然条件下的情况相差3~10倍以上。同样是人类活动, 在合理的土地利用、采取各种沙漠化防治措施的情况下, 又可使沙漠化过程逆转。从这一点上来说, 人为驱动因素应是起绝对主导作用的。 相似文献
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西藏"一江两河"中部流域地区土地沙漠化变化的驱动因素分析 总被引：21，自引：11，他引：10
土地利用/覆盖变化及其驱动力是当前研究的热点问题,现代土地沙漠化变化的机制及其驱动因素的研究更倍受关注。选择西藏"一江两河"中部流域地区为研究区域,依据该区1991年与1997年的两期土地沙漠化类型与面积数据,利用定量方法分析了同期土地沙漠化的发展变化与区内各种自然与人文因子间的数量关系,以定量辩识其变化的驱动因素。分析结果表明,该区近期土地沙漠化的变化是在多种气候因子、社会因子与经济因子共同驱动下自然变化过程与人为变化过程相互影响的结果,其中,自然驱动因素主要是风力与干旱程度,人为驱动因素主要是农作物播种面积与牲畜(超载)数量,但比较之下自然驱动因素的作用相对稍重,具有相对主导性。 相似文献
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陕北长城沿线地区土地退化态势分析 总被引：77，自引：1，他引：77
以陕北长城沿线农牧交错区为例，运用遥感与GIS技术，定性与定量相结合的方法，对研究区1985－1998年土地利用类型转换及土地退化时空规律，趋势和机制等进行了评价与分析。研究表明：该区土地退化的主导类型及土地沙漠化。从成因分析，土地沙漠化主要是长期以来的人口超载，不合理的土地利用方式和高强度的土地开发行为激发了地表自然过程伯退化性演替，致使潜在的自然环境脆弱怀转化为现实的破坏。过去13年土地退化程度部体上在不断剧，而且退化类型正向多样化发展。最后，依据评价与分析结果，进一步对该区土地退化防治和沙漠化土地生态恢复的措施与对策进行了讨论。 相似文献
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沙质草地土壤动物的研究进展及建议 总被引：6，自引：1，他引：6
中国北方农牧交错带,生态背景脆弱,在自然因素和人为活动的严重干扰下,生态系统遭到了严重破坏,草地面临严重沙化的威胁。而土壤动物是沙质草地生态系统物质循环和能量流动的不可或缺的一环,对保护和改善土地资源,控制由于各种原因而导致的土地退化、土地沙漠化有着重要意义。从沙质草地土壤动物的物种组成、研究方法、时空动态变化及其对生态系统的作用等方面进行了总结,分析了当前沙地土壤动物研究中存在的问题,并为未来沙地土壤动物研究提出了一些建议,从而为沙质草地生态系统恢复和重建及沙漠化逆转等提供了基础资料。 相似文献
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科尔沁沙地是中国半干旱地区沙漠化发展的典型地区和沙漠化防治的重点区域。本研究以科尔沁沙地为研究区域,以沙漠化逆转不同阶段的沙地为研究对象,通过野外调查和室内分析,采用空间代替时间的方法,在区域尺度上探讨了土壤有机碳对沙漠化过程的响应规律,并结合气候、植被和地形因子阐释了该区域土壤有机碳空间变异的主导因素。结果表明:(1)土壤有机碳含量随沙漠化程度的加剧表现出疏林草地(未沙漠化)>固定沙地(轻度沙漠化)>半固定沙地(中度沙漠化)>半流动沙地(重度沙漠化)>流动沙地(极重度沙漠化)。(2)固定沙地、半固定沙地、半流动沙地和流动沙地土壤有机碳密度分别比疏林草地降低了29.1%、49.3%、62.9%和84.1%。(3)随着沙漠化的发展,土壤质地发生粗化现象,即中、细砂粒含量明显增加,而土壤细颗粒(极细砂和黏粉粒)含量明显下降。(4)科尔沁沙地沙漠化过程中,土壤黏粉粒的损失是土壤粗化、有机碳含量下降的主要原因,而pH的变化受沙漠化影响较小。(5)气候因子是导致SOC含量受经纬度影响的主要因素,而地形因子的影响次之。 相似文献
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呼伦贝尔草原沙漠化现状、发展态势与成因分析 总被引：20，自引：5，他引：15
呼伦贝尔草原是我国优质的天然牧场和重要的畜牧业生产基地。近年来,该草原中的砂质草场已大面积发生沙漠化。通过实地调查研究,并结合遥感资料和前人研究成果,本文在分析了呼伦贝尔草原沙漠化现状和发展态势的基础上,着重从地质环境变化和人类活动两个方面探讨了该区沙漠化的成因。认为沙漠化的发展是自然因素与人为因素共同作用的结果,地质环境因素是形成沙漠化的基础,地表的土壤和植被是草原良好的保护层,人类对草原的破坏是导致沙漠化的直接原因。最后,对沙漠化的防治提出了3点建议。 相似文献