喀斯特石漠化的形成背景、演化与治理

KARST ROCKY DESERTIFICATION:FORMATION BACKGROUND,EVOLUTION AND COMPREHENSIVE TAMING

喀斯特石漠化是青藏高原隆升在其东南翼所诱发的重要地质生态灾害问题 ,是制约中国西南地区社会经济发展的关键因素。它不是一种纯自然过程 ,而是与人类活动密切相关 ,不仅造成土地资源丧失 ,干旱缺水 ,生态系统退化 ,而且使该区的贫困问题加剧 ,具有明显的自然和社会学属性。本文着重从地质和生态的角度 ,阐述喀斯特石漠化的形成特点和演化方式 ,及其对综合治理的指导意义。对西南岩溶山地而言 ,土壤和植被是生态环境中最为敏感的自然环境要素 ,与非岩溶区相比 ,具有明显的脆弱特征。它们在干扰下发生迅速演替 ,诱发地表水文条件的改变 ,导致石漠化的形成。文中特别强调岩溶山区碳酸盐岩基底岩性的不同、生态环境类型与植被演替的方式和进程的多样性对于岩溶生态系统的影响作用。基于上述认识 ,对石漠化地区的土地利用方式和生态恢复过程以及可能发展的方向提出了一些建议和看法。

Karst rocky desertification is not only a geo-ecological disaster induced by uplift of Qinghai-Xizang Plateau in its southeast flank, but also a critical factor to constrict the social and economic development of Southwest China. It is not an absolute natural process, and relates to human activity tightly. It is a process of land degradation involving serious soil erosion, vast exposure of basement rocks, drastic decrease of soil productivity and the appearance of a desert-like landscape. In essence, karst rocky desertification is caused by irrational, intensive land use in fragile karst geo-ecological environment. The process is expanding rapidly, and it is daily reducing the living space of residents and is the root of disasters and poverty in the karst areas of Southwest China. Therefore, it possesses natural and social characteristics obviously. This paper expounds emphatically the formation character and evolving mode of karst rocky desertification and its guidance significance to comprehensive harnessing from the angles of geological and ecological viewpoints. Soil and vegetation are the most sensitive elements in karst mountain areas of Southwest China and have obvious fragile characteristics compared with non-karst areas. The rapid variation of karst soil and vegetation under anthropogenic disturbance induces the changes of surface hydrological conditions and the formation of karst rocky desertification. It is specially pointed out the influence of difference of lithology of basement carbonate (carbonate rock and dolomite), the diversity of eco-environmental types and the evolving modes and processes of plants on the operation mechanism of karst eco-system and its practical guidance to ecological rehabilitation. Finally, this paper puts forward some suggestions and opinions about land use patterns and ecological rehabilitation as well as the research trends in the future.