关于中国西南石漠化的若干问题

石漠化是西南岩溶山地脆弱生态系统发生的土地退化。根据已有的经验和研究成果,深入探讨了中国西南岩溶山地喀斯特石漠化的科学内涵、成因、发展过程、评价指标及防治机理等。土壤和植被是岩溶环境中最为敏感的自然环境要素,可能是石漠化过程的主要自然成因,而以土地利用为表现形式的强烈人类活动为驱动力;石漠化的发生发展过程即人为过程→生物学过程→加速的地学过程。石漠与石漠化,二者属于完全不同的范畴,不同空间尺度的石漠化评价应有不同的评价指标、标准和石漠化生态基准的多样性,以便为石漠化的演化研究及生态重建起一定的参考作用。鉴于石漠化现象在我国现实中存在的客观性、在理论概念上的模糊性及在生态治理中的急迫性,有必要加强石漠化在不同时空尺度下的驱动机制研究,特别是人类驱动力的研究,加强原生岩溶生态系统和受损岩溶生态系统运行规律的研究。

PROBLEMS OF KARST ROCKY DESERTIFICATION IN SOUTHWEST CHINA

Karst rocky desertification is a kind of land degradation which has happened in fragile karst mountain ecosystem in southwest China. This paper intends to clarify the connotation, cause, process, evaluation index, and rehabilitation of rocky desertification in southwest China. Karst rocky desertification is a major type of desertification, the vulnerable eco-geo-environment serves as its base, especially the most sensitive soil and vegeta-tion may be the main naturai causes of karst rock desertification, violent human impaction as its driving force, and the most important cause is the irrational human activities including overgrazing, deforestation and cultiva-tion. All of these factors led to the degradation of ecosystems, and ultimately to the desert-like conditions in the humid areas of southwest China, including man-made process, biology process, accelerated water and soil loss process. It is very important to establish evaluation criteria for different types of rocky desertification land in dif-ferent scale and different karst geomorphic types, including naturai criteria, biology and agriculture criteria, so-cial criteria. It is also indicated that the present controversy on the process and mechanism of rocky desertification in southwest China is largely due to the misunderstanding on the concepts of "rocky desertification" and "rock desert". Because of the objectivity in reality, the illegibility in concepts and the exigency in eco-environ-mental construction, the driving mechanism in different spatial-temporal scale, particularly the human driving force, and the evolvement of original and degraded karst eco-systems must be studied further.