滇池沉水植物的分布格局及其水环境影响因子识别

Distribution pattern of submerged macrophytes and its influencing factors of water environment in Lake Dianchi

研究滇池沉水植物的分布及其与水环境因子的关系,对于滇池沉水植物的恢复具有重要的指导意义.2016年4-11月对滇池24个典型点位沉水植物群落特征进行调查,共发现16个调查区存在9种沉水植物,以篦齿眼子菜(Potamogeton pectinatus)、微齿眼子菜(P.maackianus)、穗花狐尾藻(Myriophyllum spicatum)、轮叶黑藻(Hydrilla verticillata)、马来眼子菜(P.wrightii)等为主,沉水植物主要分布在近岸3 m以内水域,盖度在10%左右.主成分分析结果表明,总氮、总磷、悬浮物、化学需氧量和叶绿素a浓度是影响沉水植物种类和生物量的主要因素,透明度是影响沉水植物盖度的主要因素;典范对应分析结果显示,滇池沉水植物的分布主要受水体中营养盐含量和化学需氧量的影响,穗花狐尾藻和轮叶黑藻对有机物和藻类的耐受能力较强,马来眼子菜和篦齿眼子菜适于生长在高营养盐的环境.滇池沉水植物恢复初级阶段的关键是降低水体中化学需氧量、抑制藻类的生长,其次是控制水体营养盐浓度.按照"一区一策"的原则,草海东风坝内和外海南部适于进行沉水植物恢复,外海北部实行控藻治理,外海东部需改善水体有机物浓度和营养盐条件,外海西部以沉水植物自然保育为主.

Studying the distribution of submerged macrophytes and the influencing factors of water environment is of significance for the recovery of submerged macrophytes in Lake Dianchi. Field surveys for characteristics of submerged macrophytes were carried out at 24 typical regions in Lake Dianchi from April to November,2016. A total of 9 submerged macrophytes species were recorded in the 16 study regions. Potamogeton pectinatus,P. maackianus,Myriophyllum spicatum,Hydrilla verticillata and P. wrightii were the main submerged macrophytes species in Lake Dianchi. The depth of submerged macrophytes was less than 3 m,which was 10% of the whole lake area. Principal component analysis showed that total nitrogen,total phosphorus,suspended solids,chemical oxygen demand,transparency and chlorophyll-a were the main influencing factors for the distribution and biomass of submerged macrophytes,whereas transparency was the main influencing factor for the coverage of submerged macrophytes. Canonical correspondence analysis indicated that the distribution of submerged macrophytes was mainly influenced by nutrient concentrations and chemical oxygen demand. M. spicatum and H. verticillata are tolerant species of organic matter concentration,and algae. P.wrightii and S. pectinata are adaptive to high nutrients concentration. Reducing chemical oxygen demand and algae biomass will be crucial to submerged macrophytes restoration,with controlling the nutrients level in water as the second. According to the principle of"one district one policy",the inside of Dongfeng dam and the southern lake should be the prior place to be restored,while the northern lake should be the place to control algae at first. The eastern lake should cut down the organic matter and nutrients concentrations. The western lake should be under natural protection.