太子河流域水生态功能Ⅱ级区的划分

Technique for Freshwater Ecosystem Functional Management Level Ⅱ Region in Taizi River Basin

流域水生态功能Ⅱ级区是实施流域层面水生生物多样性保护的重要依据.以太子河流域为研究对象,开展分区指标筛选技术方法研究,通过指标的空间变异性、主导性及其与水生态因子相关性分析,从年均气温、年降水量、年蒸发量、高程、坡度、坡向和NDVI(归一化植被指数)等备选分区指标中筛选出适宜分区指标,在此基础上采用ISODATA(迭代自组织数据分析方法)非监督分类方法划分了太子河水生态功能Ⅱ级区.结果表明,高程和NDVI具有良好的空间敏感性、主导性以及与水生态因子的相关性,可以反映地貌和植被对太子河水生态系统的影响,是太子河流域水生态功能Ⅱ级区划分的适宜指标.采用上述指标可将太子河流域划分为3个水生态功能Ⅱ级区:①上游山地森林河流水生态亚区,平均海拔511 m,区内以浅水性鱼类和激流性大型底栖动物为主;②中游丘陵森林河流水生态亚区,平均海拔282 m,区内以溪流性鱼类和缓流性大型底栖动物为主;③下游平原农业河流水生态亚区,平均海拔65 m,区内多受人类活动干扰,以耐污性大型底栖动物为主,少见鱼类.

The level II of freshwater ecosystem functional management region （FEFMR） is the basis for freshwater biodiversity conservation. The delineation method for FEFMR level II was presented for the Taizi River basin as the case study area. Based on spatial variation analysis of environmental indices, predominance analysis and its relationship with ecological factors, delineation indices were filtered from the candidates including annual average temperature, annual rainfall, annual evaporation, elevation, slope, aspect, and normalized difference vegetation index（NDVI）. Subsequently, the FEFMR level II was delineated with.the iterative self-organizing data analist techniues dgorithm （ISODATA） method, an unsupervised classification method, and freshwater ecosystem features were summarized for each region. Results showed that elevation and NDVI were proper classification factors since they were spatially sensitive, predominantly and significantly correlated with freshwater ecosystem factors, and could reflect the influences of geomorphology and vegetation type on freshwater ecosystem in the study area. The Taizi River basin was delineated into three regions named ： 1 ） highland forest freshwater ecological subecoregion, which is at the mean altitude of 511 m and dominated by shallow water fish species and wildwater macroinvertebrate species; 2） midland midland forest freshwater ecological subecoregion, which is at the mean altitude of 282 m and dominated by stream fish species and subcritical flow invertebrate species; and 3 ）lowland plain farmland freshwater ecological subecoregion, which is at the mean altitude of 65 m, frequently disturbed by human activity, and dominated by macroinvertebrates pollution tolerant of pollution, with few fish fund.