南京市湿地水质对城市化影响强度的响应研究

选取28个受城市化影响程度不同的典型湿地,对其水质进行连续监测.另一方面利用GIS技术及景观生态学原理对城市湿地所在集水区不透水类型及林地类型进行景观分析,并构建城市化影响指数(UEI),进一步对区域城市化水平与湿地水质进行相关分析.结果表明:①南京仙林新市区湿地水质季节性变化表现为夏季水质较差,冬季水质相对较好,春、秋季节差别不大.②湿地水质与城市化水平有着明显的相关关系,城市化水平等级越高,湿地水质越差,其中高等城市化水平(HU)湿地TP、TN、NH4+-N、Chla等富营养化指标质量浓度分别达到0.27、1.07、0.15、17.94 mg.L-1,而低等城市化水平(LW)湿地其质量浓度则分别为0.12、0.56、0.12、4.85 mg.L-1.③城市化影响指数与湿地水质存在着阈值关系,整体来看,当UEI值超过2.2时,湿地水质恶化速度加快.

Responses of Wetland Water Quality to Influence the Strengthness of Urbanization in Nanjing, China

28 typical wetlands were selected to monitor the contaminants in water monthly, that influenced by urbanization in different scales. On the other hand, the land use types such as impervious area and forest area in the catchments of urban wetlands were analyzed by GIS and landscape ecology. And then the effects of urbanization index (UEI) was employed to reveal the relationship between urbanization level and water quality in Xianlin New City of Nanjing. Results indicated that: 1 the seasonal variations of water quality showed that water quality in summer was worse than those in other seasons, and the water quality in winter was good. However there were no significant differences between the spring and the autumn. 2 the relationship was significant between urbanization level and water quality, and the water quality tended to be getting worse when the urbanization level was getting higher. The concentrations of TP, TN, NH₄⁺-N, and Chla were 0.27, 1.07, 0.15 and 17.94 mg·L^-1respectively in the high urbanization(HU) level wetland while the concentrations were 0.12, 0.56, 0.12 and 4.85 mg·L^-1 in the low urbanization(LW) level wetland. 3there was a threshold between UEI and the water quality. On the whole, the water quality would get worse quickly when the value of UEI exceeded 2.2.