Spatial distribution of karst cave resources in south-western Hubei region

A karst cave is one of the most important geological tourism resources. China possesses about 9.1×105 km2 the karst terrain, and accounts for approximately 1/10 of the whole land surface of the country. There are 6 provinces in southwest China, including Sichuan, Hubei, Hunan, Guangxi, Guizhou and Yunnan. This area is the largest and concentrated karst distribution area in the world, commonly known as "Southwest China Karst Area". Southwestern Hubei is in the northeast of the area and in the southwest of Hubei Province. It contains two cities and six counties of Enshi Tujia and Miao Autonomous Prefecture, as well as two counties of Yichang City, which is about 29,000 km2. The strata in the area are dominated by the thick marine carbonate rocks, and the exposed area of carbonate rocks accounts for 61.6% of the total. Its overall topography is the slope from the west to the east, which controls both the development and flow of the major water systems in the area, and the development and distribution of the tourism karst caves in the southwest Hubei.The spatial distribution of the karst cave tourism resources is the focus of tourist cave research and survey. In order to quantitatively analyze the distribution patterns and characteristics of the tourism karst caves in the southwest Hubei, and to provide the scientific basis for the investigation, planning and development of the resources in the future, this paper first obtains the basic geographic information of 73 tourism karst caves in the southwest Hubei. Firstly, on the basis of the secondary data and on-the-spot investigations, the geographical database for these caves was then constructed using ArcGIS software. Secondly, the distribution patterns, the horizontal and vertical distribution characteristics of the caves were analysed, respectively, using the methods of nearest proximity analysis, buffer analysis and cluster analysis built in the ArcGIS spatial analysis. The analytical results show that, (1) The karst cave tourism resources, in the ten counties of the southwest Hubei, are mainly distributed in the zones within the scope of 2.5 km along main rivers and within 1.8 km along the tributaries of the main rivers ; (2) Additionally, they form a ladder-like distribution with five levels including low altitude karst caves, low-middle altitude karst caves, middle altitude karst caves, middle-high altitude karst caves and high altitude karst caves.