Research On Optimal Regionalization In Karst Peak-cluster Depression Regions

The karst area in southwestern China is a typical ecologically fragile area and the largest concentrated contiguous poverty area in China.And it is the area that the development of karst is the most typical,landform types are complete the problems of rocky desertification and poverty are intertwined.The peak-cluster depression is the largest karst landform type area with deep rocky desertification.Under the background of large-scale ecological protection and construction,the area of ??rocky desertification has achieved “continuous net reduction”,but the existing governance division mainly considers karst landform features,and the division is relatively extensive,ignoring the high landscape heterogeneity and geographical division of different karst areas.The opposite sex restricts the regional orientation and sustainability of rock desertification control.This study considers the micro-geomorphology(cone karst,tower karst and normal karst)and the geological,topographic and climatic constraints of the karst peak cluster area,and uses the geographical correlation method,the spatial superposition method and the dominant sign method to combine the research methods.Field investigations carried out the optimization of natural regions of karst peak clusters,and preliminarily clarified the characteristics of natural geographical differentiation and social and cultural differences in different peak clusters,and revealed the main problems of rocky desertification control in different peak clusters.The future governance direction,the research results have important guiding significance for the future rock desertification control of karst peak clusters.(1)Partition principle and index: according to the similarity of rocky desertification of karst mountain dominant factor,similarity of the dominate factor of land use,climate,vegetation similarity,desertification control countermeasures and measures of similarity,regional integrity,considering the karst peak-cluster depression area geology,climate and topography factors such as the similarities and differences on the space,select the lithology and the proportion of land area less than 6 degrees as the primary partition indexes;Climatic vegetation zonation is used as the secondary zoning index.The dominant slope and its variation and topographic relief are used as the three-level zoning indexes.(2)The peak-cluster depression is divided into two primary zones: non-karst zonedominated by clastic rocks and karst zone dominated by carbonate rocks.The proportion of carbonate area in non-karst areas is less than or close to 20%,or the proportion of clastic rock area is greater than or close to 60%.Compared with the gentle slope and thick soil in karst areas,normal mountains are mainly formed,with the highest vegetation coverage and good ecological environment.(3)In the secondary subdivision,karst is divided into untypical peak-cluster depressions area of southwest monsoon and typical peak-cluster depressions of east Asian monsoon.The development of karst landforms in the untypical peak-confluence depression area of southwest monsoon is dominated by climatic factors,with relatively little rainfall,low proportion of paddy soil area and the strongest degree of soil erosion.(4)According to the great geomorphologic position and the micro-geomorphologic morphology of the peak-cluster depressions in the study area,the typical peak-cluster depressions in the east Asian monsoon are further divided into the peak-cluster depression subzone of shallow dish type in the southwest Guizhou Plateau,the funnel-shaped cone peak-cluster depression in southern Guizhou and northern Guangxi,the funnel-shaped tower and cone peak-cluster depression in South of the great slope of central Guangxi and the shallow-dish-type cone and tower peak-cluster depression in southern Guangxi.(5)Characteristics of the third-level zoning: The funnel-shaped tower and cone peak-cluster depression in South of the great slope of central Guangxi has abundant precipitation,typical karst landforms,serious soil erosion and the scarcity of cultivated land resources.The average elevation of the peak-cluster depression subzone of shallow dish type in the southwest Guizhou Plateau is the highest at 1317.96 meters,with an average undulation of 105.77 meters and the lowest vegetation coverage.The funnel-shaped cone peak-cluster depression in southern Guizhou and northern Guangxi has a large topographic relief,but the central terrain is flat,the proportion of the dam area is large,and the rain and heat are in the same period,and the climate is suitable.The shallow-dish-type cone and tower peak-cluster depression in southern Guangxi has the lowest average undulation,the thickest soil layer,the average soil thickness of 92.30 meters,and good hydrothermal conditions,which is the best area for cultivated land resources in the study area.(6)The untypical peak-cluster depression area of southwest monsoon and the funnel-shaped tower and cone peak-cluster depression in South of the great slope of centralGuangxi.The terrain is undulating,the traffic is occluded,the per capita arable land is low and the quality is poor,and the contradiction between people and land is serious.The per capita GDP is low,which is seriously affected by rocky desertification and is lagging behind.It is the key area for governance;the peak-cluster depression subzone of shallow dish type in the southwest Guizhou Plateau and the funnel-shaped cone peak-cluster depression in southern Guizhou and northern Guangxi have superior geographical location.The economic development speed of the industrial and service industries is high,and the urbanization level is high.The economic development of the two regions is less dependent on the rocky desertification land,and the rock desertification control should be based on the protection;The shallow-dish-type cone and tower peak-cluster depression in southern Guangxi have many per capita arable land,rich in water and heat resources,and relatively moderate human-land relationship.The utilization efficiency of rich water and heat resources should be improved,and the long-term benefits of ecological management should be obtained.(7)Considering the different natural environmental conditions,socio-economic conditions and the effectiveness of rocky desertification control in each sub-area,the future karst peak-cluster depression rocky desertification control should strengthen the intensive use of land,the upgrading and rebuilding of stone hillside shrubs and shrubs according to the characteristics of different sub-areas.The stone forest growth environment adapts to the characteristics of high-efficiency economic forestry and fruit industry cultivation,traditional plantation ecosystem construction,and comprehensively combines the ecological benefits and economic benefits of the desertification control,short-term benefits and long-term benefit.