LAND DEGRADATION AND ECOLOGICAL REHABILITATION IN KARST AREAS OF GUIZHOU PROVINCE, SOUTHWEASTERN CHINA

Abstract

The scientific community has paid close attention to the ka rst region for its unique environment. Early research mainly focused on inorganic natural environment, such as hydrology, geology and geochemistry of the karst area. In the past decades, land degradation in karst area has become more and more serious, even lead to rocky desertification. The fragile ecosystems and human activities in the region attract more and more attention gradually. The karst area in the southwestern China is the largest continuous karst zone in the world. Population pressure and poverty are typical in this area. The economy is in underdevelopment. The ecology is fragile and the land is degrading seriously. Therefore, the contradiction between man and the nature is unusually fierce. To reconstruct the environment and promote the development of society and economy become out of most urgent tasks in the Western Development of China. Fragile environment, increasing population pressure and continual land degeneration result in the impossibility for some karst area to rely on it's own strength to reform ecology. So it's necessary to carry out the ecological rehabilitation based on the scientific research, management and plan, and to increase related external input. This paper has summarized the theory, method, technology and model of ecological rehabilitation. The author considers land degradation of the karst area as the representation of the regional man-nature complicated huge system structure and its disorderly function. So unilateral environmental protection and simple ecological management are not enough to solve this kind of systematic problem. The ecological rehabilitation of the area needs to utilize the thought and methods of systematic science. The following issues are need to be studied furthermore: ① The land degradation process in the past 30～50 years; ②The contribution of human and natural factors respectively to land degradation; ③Human's driving force to land degradation, such as social economic factors, policy and the habits of the local people, etc.;④The key process of land degradation and the th reshold of advancing degradation to system crashing; ⑤The principle, theory, method and technology of ecological rehabilitation ; ⑥Scaling and coupling of different spatial scales;⑦The security system of regional ecology rehabilitation.