基于生态脆弱性评价的松花湖湖滨带功能区划研究

Lakeside Function Division of Songhua Lake Based on Ecological Vulnerability Evaluation

通过收集松花湖湖滨带水文、水质、地貌等资料,对卫星遥感影像进行遥感解译和空间统计分析,选取丰水期和平水期两个时期,对不同土地利用类型附近的湖滨带近岸水体营养物质进行采样调查与实验分析,以压力-状态-响应模型为基础,围绕湖滨带人工干扰程度、湖岸稳定性、湖滨带植被覆盖情况、总氮浓度、总磷浓度、叶绿素浓度,建立松花湖湖滨带生态脆弱性评价指标体系,利用层次分析法对其生态脆弱性进行评价,结合各地点生态脆弱性评价结果与行政区划,对松花湖湖滨带进行功能区划,并针对各功能区提出生态修复措施。结果表明,松花湖湖滨带的土地利用方式以耕地为主,占湖滨带总面积44.91%,其次是水域及水利设施用地与草地,分别占19.96%和19.21%,林地、交通运输用地与住宅用地的比例较低,分别占7.97%、4.64%、3.30%;湖滨带水体总氮浓度为2.04mg/L,总磷浓度为0.23mg/L,叶绿素浓度为6.25μg/L,景区、耕地的总氮、总磷、叶绿素含量高于其它区域;湖滨带生态脆弱性指数1.412~7.953,平均值为3.78,总体处于轻度脆弱,西部地区处于轻度脆弱,东南部地区处于微度脆弱,东北部地区处于重度脆弱;根据脆弱性级别将湖滨带划分为4个功能区,为非点源污染防治区、旅游观光开发区、湿地生态保护区、蛟河生态重建区。对松花湖湖滨带进行区划并提出分区生态修复重点,可为该区域生态修复提供技术支撑。

Songhua Lake is one of the drinking water sources for Jilin Province.In recent years,excessive agricultural planting has encroached on the lakeside wetland,leading to excessive nutrient loading of the river and threatening the ecology of Songhua Lake.The lakeside area acts as a transition and buffer zone for the aquatic ecosystem,but is ecologically vulnerable.In this study,we assessed the ecological vulnerability of the Songhua lakeside area using an ecological vulnerability evaluation system and the results were used to divide the shoreline area into zones according to ecological function.The ecological vulnerability evaluation system for Songhua Lake was based on a stress-state-response model and field surveys of land use type,water quality,hydrology,landform and other lakeside data.The system included six evaluation indices:degree of disturbance,stability,lakeside vegetation cover,and total nitrogen,total phosphorus and chlorophyll in lakeside water.The weighting of each index was calculated using the Analytic Hierarchy Process(AHP)method.In September 2016and May 2017,a water quality investigation was carried out at 32sampling sites and hydrology,landform,fish aquaculture and other lakeside data was also investigated.Land use was analyzed by interpreting images collected by remote sensing.Land use in the Songhua lakeside was dominated by arable land(44.91%),followed by water conservancy facilities land(19.96%)and grassland(19.21%).Woodland,transportation and residential areas were relatively low,respectively accounting for 7.97%,4.64%,and 3.30%of total land use.Total nitrogen,total phosphorus and chlorophyll concentrations in lakeside water were,respectively,2.04mg/L,0.23mg/L and 6.25μg/L.The levels of total nitrogen,total phosphorus,and chlorophyll around scenic spots and arable land were clearly higher than those in other areas.The ecological vulnerability index of Songhua lakeside ranged from 1.412 to 7.953and the average index value of 3.78indicated mildly fragile conditions.The western part of the lakeside zone was also mildly vulnerable,the southeastern part was slightly vulnerable and the northeastern part was severely vulnerable.According to the level of vulnerability,the lakeside was divided into four functional zones:(1)non-point source pollution prevention and control zone,(2)tourism and sightseeing development zone,(3)wetland ecological protection zone and(4)Jiaohe ecological rehabilitation zone.Finally,ecological restoration measures were proposed for each zone.This study provides technical support for treating and restoring lakeside zones,and for protecting the self-regulating virtuous cycles of ecosystems threatened by human activities.