Integrated Restoration of Small Watershed in Karst Regions of Southwest China

Abstract

Karst is a type of landscape which forms under a specific combination of geological conditions, precipitation, and temperature (Fleury 2009). It contains caves and extensive underground water systems that develop from especially soluble rocks such as limestone, marble, and gypsum (Ford and Williams 2007). Karst regions have always been characterized by environmental problems such as an impoverished ecosystem, soil degradation and erosion, deterioration of water quality and landform destruction (Urich 2002). Thus, a karst region can be considered among the most vulnerable land systems in the world. The Karst mountainous region of Southwest China is one of the largest karst continuum belts in the world (Huang et al. 2008). Karst geomorphology is mainly concentrated in the Yunnan, Guizhou, and Guangxi provinces. There, the karst system experienced rocky desertification, a process of land degradation whereby an area formerly covered by vegetation and soil is transformed into a rocky landscape almost completely devoid of soil and vegetation. Rocky desertification always leads to progressive impoverishment of local residents, a situation typically exacerbated by pressures from population growth and improper uses of land (Yuan 1997). At one time researchers called it “cancer of the land” (Zhang et al. 2006). Degradation is most severe in Guizhou province (Zhang et al. 2006; Huang et al. 2008). Biophysical characteristics such as seasonal drought and floods, vegetation degradation, soil erosion, and landslides together with such social-economic issues as poverty and concentrated ethnic minority groups living in remote and less developed areas with low education level, make for a more critical situation than in other provinces (Xing et al. 2009). The total area of Guizhou province is 176 167 km2, of which 92.5 % is hilly and 61.9 % is karst (Xiong 2002). In 2005, 21.3 % of the land was under rocky desertification, while another 31.2 % was in the process of being transformed into rocky desertification land (Fig. 1) (Xiong et al. 2009). There were 23.0 million people, or 66.2 % of the total population, living in the rural areas of Guizhou province in 2010 (Guizhou Bureau of Statistic 2011). On a national level nearly 50.3 % live in rural areas (National Bureau of Statistics 2011). Per capita cultivated land is less than 0.05 ha. In order to make a living in such harsh conditions, local peasants have to cultivate sloping fields, which leads to environmental degradation and further poverty. This vulnerable environmental system co-evolves with a lagging social economy deems this region a hotspot calling for policy attention and research. Interrupting the cycle of poverty is difficult and complex: because of the fragile socio-ecological system, most of the local inhabitants live on subsistence agriculture, it is difficult to extract themselves from poverty trap without external intervention (Reynolds et al. 2007), so assistance from outside such as government, NGOs, and foreign aid is needed. Fig. 1 Rocky desertification rate in Guizhou province (based on data from (Guizhou Bureau of Statistic 2010) Following the great floods in 1998, and in consideration of Guizhou being located at the headwater of Zhujiang and Yangtze river, particular focus was given to the rehabilitation of the ecosystem on the part of national decision-makers (Xiong et al. 2009). From then on, local government and researchers have undertaken a lot of measures to combat further degradation of the fragile environment. Some of the measures succeeded as reported by Zhang et al. (2006). The Chinese central government made a commitment in 2005, to input billions of dollars over the 2008–2015 period to restore the ecosystem in 451 counties of Southwest China experiencing severe rocky desertification. There are 78 counties in Guizhou province, of which 55 were established as pilot projects between 2008 and 2010. A systematic strategy, Integrated Restoration of Small Watershed (IRSW), was devised to apply in these 78 counties between 2011 and 2015. Different from simple measures of ecosystem recovery at site scale (Zhang et al. 2006) and recommendations for antidesertification and researches reported before (Huang et al. 2008), this paper provide a detailed illustration of the systematic approach, Integrated Restoration of Small Watershed (IRSW), for ecosystem restoration in karst areas.