北京市凉水河物理栖息地完整性评价

针对城市河流强人为干扰特征,从横向完整性、纵向完整性和垂向完整性3个维度选择了10个评价指标,引入信息熵对传统的灰色聚类评价方法进行改进,构建城市河流物理完整性评价指标体系。利用该方法对北京市凉水河物理栖息地完整性开展了评价,结果表明在监测的21个采样点中评价结果为好、较好、一般和较差的比例分别为19.1%、23.8%、33.3%和23.8%,造成凉水河物理栖息地完整性较差的指标依次为生态流量满足率、纵向连通性指数和河流蜿蜒度。导致凉水河物理栖息地完整性较差的突出原因为生态流量满足率低、闸坝较多及土地利用不合理,其中闸坝出现的周期性与物理栖息地变差的周期性相一致。

Evaluation of physical habitat integrity of Liangshui River in Beijing

Considering the strong human disturbances of urban rivers, 10 evaluation indexes from three dimensions of horizontal integrity, longitudinal integrity and vertical integrity were selected. The traditional grey clustering evaluation method was improved by introducing information entropy to construct the urban river physical integrity evaluation index system. This method was used to evaluate the physical habitat integrity of Liangshui River in Beijing. The results show that: among the 21 monitoring sites under the evaluation of physical habitat integrity, evaluation results were defined to be four grades of good, better, medium and poor, accounting for 19. 1%, 23. 8%, 33. 3% and 23. 8%, respectively. The indicators leading to poor physical habitat integrity of Liangshui River are the low ecological flow(EF), longitudinal connectivity(LC), and river meandering(RM)in sequence. The prominent reasons that cause poor physical habitat integrity of Liangshui River attribute to low ecological flow, more dams and unreasonable land use. The periodicity of the emerging dam is consistent with the same of the physical habitat deterioration.