不同地质背景下岩溶生态系统的自然特征差异——以茂兰和花江为例

自然特征是典型岩溶生态系统研究与评价的基础。西南岩溶山区,由于气候、地形、地质构造、岩溶作用、土壤等条件的不同,各圈层发生着地质地貌组合→水文土壤组合→植被和小生境组合结构的作用过程,不同组合结构的岩溶生态系统具有特殊的功能和圈层的耦合作用,其本底稳定性与脆弱性各异,从而形成了不同区域岩溶生态系统及生境类型的多样性。对茂兰岩溶森林区和花江峡谷区两种典型岩溶生态系统———岩溶原生森林系统与石漠化系统的自然特征对比研究表明,两者的差异集中体现在地质构造、地貌演化、岩溶形态、水文结构、土壤侵蚀、植被群落、水文生态效应与生境多样性等方面,其中地质构造、地貌演化、岩溶形态、可开发利用的水资源、植被群落是两种系统存在显著差异的关键因素。因此,有必要探讨不同岩溶地貌单元、不同碳酸盐岩类型区的岩溶生态系统基本生态过程的共性和差异,探索地质环境与生态环境的内在联系和耦合关系,分析地质因素对生态环境的控制和影响程度,为岩溶受损生态环境单元的恢复重建提供理论依据。

DIFFERENCES IN NATURAL CHARACTERISTICS FOR KARST ECOSYSTEMS UNDER DIFFERENT GEOLOGICAL BACKGROUNDS AS EXEMPLIFIED BY MAOLAN AND HUAJIANG ECOSYSTEMS

The natural characteristics are the basis for evaluating typical karst systems. There have been found some processes of geological and geographical combination, hydrological and soil combination, vegetation and microhabitat type combination in karst ecosystems in southwestern karst mountainous regions due to differences in climate, landform, geological tectonics, karstification, soil, etc. Karst ecosystems characterized by different combination structures have special functions and coupling actions of biosphere, geosphere, pedosphere, hydrosphere, and atmosphere, and have different background stabilities and fragilities, therefore, forming karst ecosystem and microhabitat diversity in different regions. By comparing the natural characteristics between two karst ecosystems, i.e., the typical karst primitive forest in Maolan and the typical karst rock desertification ecosystem in the Huajiang Gorge, their differences are reflected by geological tectonics, landform evolution, karst form, hydrologic structure, soil erosion, vegetation community, hydro-ecological effect and microhabitat type. Among them, geological tectonics, landform evolution, karst form, exploitable and usable water and vegetation community are the key factors that lead to differences between the two systems. Therefore, there are necessities to discuss the similarity and difference of karst ecosystems in different karst landform units and different carbonate sections, discuss the inherent and coupling relations, analyze the impact and control of geological elements on eco-environment. All this provides the scientific basis for the restoration and rehabilitation of damaged karst eco-environment.