Relationships Between the Spatial Distribution of Karst Land Desertification and Geomorphology,Lithology,Precipitation,and Population Density in Guizhou Province
ZHANG Xin-bao1,2,WANG Shi-jie2,BAI Xiao-yong2, CHEN Wei-yan1,3,ZHANG Si-yu3(1 Key Laboratory of Mountain Environment Evolvement and Regulation,Institute of Mountain Hazards and Environment,Chinese Academy of Sciences,Chengdu 610041,China; 2.State Key Laboratory of Environmental Geochemistry,Institute of Geochemistry, Chinese Academy of Sciences,Guiyang 550002,China;3.University of Chinese Academy of Sciences,Beijing 100049,China)
This study reveals the spatial distribution of degraded karst landscape in Guizhou and concludes that it is well related to ground substance and climate(precipitation) conditions,but not well to current human activities(population densities).It is expressed as follows:(1) The spatial distribution of the geomorphologic type,dominated by chemical erosion,is well related to pure carbonate rocks in Guizhou,where peak cluster landforms are mostly distributed in the area south of the Weining-Bijie-Guiyang-Kaili line with the annual precipitation of ≥1200 mm and more tower karst hills appear as precipitation increases.In the northwest of Guizhou with the annual precipitation of ≤1100 mm,dominated by chemical erosion,north of the Weining-Bijie line,and in the area,dominated by chemical-fluvial erosion,north of the Bijie-Guiyang-Kaili line,there are mostly normal hills with few peak clusters.(2) The karst land desertification severities are well related to karst landform types,but not to population densities,in Guizhou.In the area south of the Weining-Bijie-Guiyang-Kaili line,where peak cluster landforms develop well,karst land desertification in the counties of central Guizhou with population densities of 300~400/km2 is not severer as in the counties of Southwest Guizhou with population densities of 200~300/km2 and in the counties of South Guizhou with population densities of 100~200/km2.Destruction of forests is the main driving force to karst land desertification in Guizhou.Except for a few natural karst forests,such as the Maolan Park in Libo County,the original natural forests were massively destroyed during the history,either in the areas with high population densities or in the areas with relatively low population densities.As the restored extent of secondary vegetation depends largely on the soil conditions on hill slopes,the spatial variation of karst land desertification severities is mainly controlled by soil and rock compositions on the ground,frankly speaking,by the proportion of bared rock hill land.
【Fund】： 国家重大科学研究计划项目(2013CB956704);; 中国科学院战略性先导科技专项重大课题(XDA05070400);; 贵州省重大科技专项(黔科合重大专项字〔2012〕6015号);; 国家自然科学基金项目(41001162);; 贵州-毕节-中国科学院联合资助项目(省地院合2011-4);; 贵阳市科技局项目(筑合同号);; “西部之光”之西部博士专项(科发人教字〔2012〕179号)
【CateGory Index】： X171
【CateGory Index】： X171