洱海流域水生态分区

分区边界的确定是生态分区的重要步骤,但目前多数水生态分区的边界确定以定性分析、专家判断为主。本研究以洱海流域为例,建立了一套两级分区体系。该体系基于GIS技术,用子流域作为分区基本单元,并用相关分析法,定量筛选一、二级分区指标。其中,一级分区指标为高程、坡度和植被归一化指数(NDVI),二级分区指标为农田百分比和城镇百分比。通过指标图层的叠加和重分类,合并同质性子流域,从而将洱海流域划分为5个一级区和9个二级区。藻类群落分布的验证结果表明分区合理。本研究将定量分析和子流域边界应用于水生态分区,使分区边界的确定更科学,在实际管理中更具有可操作性。本研究结果为水生态分区研究提供了新的方法,为洱海流域水生态管理提供了基本管理单元。

Aquatic eco-regionalization of Erhai Lake Basin, Yunnan Province of Southwest China

Delineation of regional boundary is an important procedure in ecological regionalization,but at present,this delineation for aquatic eco-regionalization is mostly dependent on qualitative analysis and expert judgment.In this paper,a two-level eco-region framework was established to delineate the aquatic eco-regions in Erhai Lake Basin.In this framework,sub-basin was taken as the basic unit based on GIS technique,and the indices for the two-level regionalization were quantitatively screened by correlation analysis.Altitude,slope,and normalized difference vegetation index were identified as the indices for level I,and farmland and urban area percentages were the indices for level Ⅱ.The index maps were overlaid and re-classified,and the sub-basins were further merged into several regions.Five level-I eco-regions and nine level-Ⅱ eco-regions were delineated finally.The examination through the comparison of the distribution of algal communities in different eco-regions showed that the regionalization result was reasonable.It was suggested that applying quantitative analysis and sub-basin boundaries in aquatic eco-regionalization could make the delineation of regional boundary more scientific and the actual management more operational.This study provided a new method for the study of aquatic eco-regionalization,and the basic units for the aquatic ecological management of Erhai Lake Basin.