喀斯特峰丛洼地石漠化治理自然地域分区

峰丛洼地是我国西南地区面积最大的喀斯特地貌类型区,水热资源相对较好,由于其较高的景观异质性,该区面临着石漠化治理投入与分区粗放、治理技术与模式区域针对性不强等问题,亟需开展面向石漠化治理的喀斯特峰丛洼地自然地域分区。基于修正的地质图将峰丛洼地区划分成碎屑岩为主的非喀斯特区和碳酸盐岩为主的喀斯特区,依据气候分异特征将喀斯特区划分为滇东南桂西南西南季风非典型峰丛洼地区和东亚季风典型峰丛洼地区,进一步依据大地貌部位及微地貌特征将东亚季风典型峰丛洼地区细分为黔西南高原面浅碟型锥峰洼地区、黔南桂北大斜坡北部漏斗型锥峰洼地区、桂中大斜坡南部漏斗型锥塔峰洼地区和桂南丘陵浅碟型锥塔峰洼谷区等亚区。分区结果表明各分区自然地域特征鲜明:碎屑岩为主的非喀斯特区坡缓土厚,人口压力相对舒缓;西南季风非典型峰丛洼地区受气候影响显著,地貌形态以常态山为主;桂中大斜坡南部漏斗型锥塔峰洼地区重度、极重度石漠化问题突出,但削减快、治理成效显著;黔西南高原面浅碟型锥峰洼地区人地矛盾最为尖锐,石漠化问题严重;黔南桂北大斜坡北部漏斗型锥峰洼地区石漠化比例相对较低、喀斯特景观资源丰富;桂南丘陵浅碟型锥塔峰洼谷地区水热资源最为充沛、人地关系相对缓和。面向石漠化治理的喀斯特峰丛洼地自然地域分区明确了分区的自然与社会经济条件差异,有助于提升石漠化治理的区域针对性和可持续性。

Natural regionalization for rocky desertification treatment in karst peak-cluster depression regions

Karst peak-cluster depressions are the largest karst landforms in southwest China. Compared with other karst landforms, the hydrothermal resources in peak-cluster depressions are relatively abundant. Due to the heterogeneity of this region, the investment and governance for rocky desertification treatment is extensive, and the treatment and governance technologies are lack of robustness and pertinence. Therefore, it is urgent to develop the natural regionalization for rocky desertification treatment in karst peak cluster depression to enhance the sustainability and pertinence of rocky desertification treatment. In this study, with the combination of the heterogeneity of geological setting, climate, geomorphic and topographic conditions of karst peak-cluster depression, we proposed a method to regionalize peak-cluster depression into different subregions. Firstly, based on the corrected geological map, karst peak-cluster depressions were divided into non-karst area dominated by clastic rocks and karst area dominated by carbonate rocks. Then, according to the characteristics of heterogeneous climate conditions, the karst area was divided into the atypical peak-cluster depression area of southeastern Yunnan and southwestern Guangxi in southwest monsoon and typical peak-cluster depression area in East Asia monsoon. Furthermore, the typical peak-cluster depression areas of East Asia monsoon were further divided into four subregions, including the shallow dish-shaped awl-peak depression subregion in southwestern Guizhou plateau, funnel-shape awl-peak depression areas in southern Guizhou and Northern Guangxi, funnel-shaped awl-tower depression subregion in central Guangxi and the southern giant slope areas, and shallow dish-shaped awl and tower peak depression subregion in southern Guangxi hills in accordance with the geomorphological location and topographic features. The regionalization results showed that the natural geographical characteristics of each subregion were apparently distinct. The landforms in non-karst area dominated by clastic rocks have gentle slope and thick soil, where population pressure is relatively relaxed. The atypical peak-cluster depression area of southeastern Yunnan and southwestern Guangxi in Southwest monsoon is dominated by normal mountains because of the significantly impacts of southwest monsoon climate. The severe and extremely severe rocky desertification are serious in the funnel-shaped awl and tower depression subregion in central Guangxi and the southern giant slope areas, while the rocky desertification in this subregion reduced more faster and the treatment efficiency are the most significant. The contradiction between human and land is the most acute in the shallow dish-shaped awl-peak depression areas in southwestern Guizhou plateau, and the problem of rocky desertification in this area is also serious. The proportion of rocky desertification treatment is relatively low and karst landscape resources are rich in the funnel-shaped awl-peak depression subregion in southern Guizhou, northern Guangxi and the northern giant slope areas. The hydrothermal resources are the most abundant and the relationship between human and land is relatively relaxed in the shallow dish-shaped awl and tower peak depression subregion in southern Guangxi hills. The natural regionalization for rocky desertification treatment clarifies the homogeneity and heterogeneity of natural and socio-economic conditions in different karst peak-cluster depression subregions, which will enhance the regional pertinence and sustainability of rocky desertification treatment.