The causes and processes responsible for rocky desertification in karst areas of southern China

The karst region of southern China is a fragile ecological zone with widespread rocky desertification. This paper describes the rocky desertification occurring in this region in terms of both natural and anthropogenic factors. During geological time periods, the region’s changing environment governed the natural rocky desertification processes, whereas during historical and modern times, anthropogenic processes have been superimposed on these natural processes. Human activities have accelerated and exacerbated rocky desertification. The period from the beginning to the middle of the Qing dynasty was an important transitional period in which human activities began to exert a particularly strong influence on rocky desertification. Since then, the effect of anthropogenic factors has increasingly exceeded the effect of natural factors. The rocky desertification process in southern China’s karst region combines surface ecological processes (including vegetation degradation and loss, soil erosion, surface water loss, and bedrock solution) with a reduction of the land’s biological productivity, leading to degradation that produces rocky desert. Controlling rocky desertification requires comprehensive development of sustainable agriculture and economic development that provides employment alternatives to agriculture and thereby promotes the rehabilitation of rocky desertified land.

Analysis on Hydrogeochemical Characteristics and Their Temporal and Spatial Variation in the Karst Catchment of Lianjiang River,Northern Guangdong Province

[ Objective] The study aimed to discuss the hydrogeochemical features and their temporal and spatial variation in the karst catchment of Lianjiang River, northem Guangdong Province. [ Method] Water samples were collected from 10 sub-drainages of Lianjiang River in July of 2012 and January of 2013, and then major chemical ions in tributaries of Xingzi River and Tongguanshui River were analyzed in detail to discuss the hydrochemistry type, spatial and temporal distribution and its causes of formation in Lianjiang River basin. [ Result] Among chemical ions in the wa- ter samples, Ca2. and HCO^- were dominant in Lianjiang River, accounting for over 70% and 80% of total concentrations of cations and anions re- spectively, followed by Mg2＋ and SO24-. The concentrations of most major ions were higher in winter than those in summer except SO4^2- concentra- tion was much higher in summer than that in winter, which was related to anthropogenic factors. From hydrochemical types, it is seen that HCO3-- Ca2＋ type in summer and HCO3--Ca2＋ ~ Mg2. type in winter were dominant in Lianjiang River, followed by the HCO3--SO4^2- · Ca2＋ type, and only two samples of Xingzi River belonged to HCO3--Ca2＋ Mg2· Na＋ type in winter. The spatial distribution regularity of chemical ions was not obvi- ous in the 10 sub-drainages of Lianjiang River. The concentrations of chemical ions changed greatly in the upper reaches but slightly in the lower reaches of Xingzi River catchment. The concentrations of chemical ions were steady in Tongguanshui River catchment with a smaller area, and it was a little higher in the upper reaches than those in the lower reaches. [ Conclusion] Natural processes, such as lithological heterogeneities and at- mospheric precipitation, contributed to the chemical composition of Lianjiang River catchment, northem Guangdong Province.

Pathway and Countermeasure of Farmers' Livelihood Transformation in the Ecological Development Area of Northern Guangdong Province from the Perspective of Ecological Protection

[Objectives]To explore pathways and countermeasures for transforming farmers livelihoods in the way of reducing their dependence on land while promoting sustainable development and alleviating ecological degradation.[Methods]A combination of field research,literature review,and policy analysis was employed to identify key factors affecting farmers livelihoods and potential strategies for transformation.[Results]The study found that developing ecological agriculture and modern agriculture,promoting agricultural transformation and upgrading,cultivating alternative industries,strengthening ecological engineering construction,and establishing diversified ecological compensation methods and supporting policies are effective strategies for transforming farmers livelihoods.[Conclusions]Implementing these strategies can help alleviate the contradiction between ecological protection and farmers livelihood development,promoting coordinated development of both.This approach not only benefits farmers but also contributes to sustainable environmental management and biodiversity conservation.