水生态学杂志

为了解武汉后官湖国家湿地公园水生态环境现状，于2020年1-12月对后官湖的水质、浮游植物和浮游动物进行了监测，并基于综合营养状态指数、生物多样性指数对后官湖水环境进行了评价，使用Spearman相关分析以及冗余分析（RDA）探究环境因子对浮游植物群落的影响。结果表明，后官湖西部湖区的总磷和高锰酸盐指数最高，年均浓度分别达到了0.11 mg/L和5.37 mg/L，是后官湖的主要污染来源。综合营养状态指数为29.15～46.97，属于中营养状态；浮游植物Shannon-Weaver指数和Pielou指数分别为1.12～1.89、0.38～0.72，显示后官湖总体上为轻度污染到中度污染状态。调查期间共检出浮游植物7门、54属，其中1月和4月主要以绿藻门和隐藻门占优势，5-12月则以蓝藻门占优势。5月、9-10月桡足类在浮游动物群落中占优势，其他月份则是轮虫类占优势。相比于2017-2019年，2020年后官湖的营养状态水平和浮游植物丰度出现了明显下降，大型浮游动物在群落中的比例则明显上升。Spearman相关分析和冗余分析表明，影响后官湖浮游植物群落的主要环境因子为水温、透明度和浮游动物丰度。后官湖环境管理的不断加强和新冠疫情导致的流域内人类活动减弱，可能是2020年后官湖水生态环境质量明显提升的原因。

In this study, monthly data were collected on water quality, phytoplankton and zooplankton in the National Wetland Park of Houguan Lake from January to December 2020. Then, the current aquatic environmental condition of Houguan Lake was evaluated based on the data collected using the comprehensive trophic level index TLI(∑) and biodiversity indices.The influences of environmental factors on the phytoplankton community were analyzed by Spearman's correlation analysis and redundancy analysis(RDA). The aim was to provide data and scientific evidence to support ecological evaluation of Houguan Lake and shallow lake conservation. Houguan Lake consists of four sub-lakes(HG1: Gaohu Lake; HG2:Bailian Lake; HG3: Zhiyin Lake;HG4: Tian'e Lake) and an outflow river(HG5: Dagudu River). Water samples were collected in each section and the outflow river for determination of water quality parameters,phytoplankton and zooplankton each month except February and March(due to the COVID-19 pandemic).The concentration of total phosphorus and CODMn, were highest in the western lake(HG1), with respective average annual values of 0.11 mg/L and 5.37 mg/L. The comprehensive trophic level index of Houguan Lake ranged from 29.15 to 46.97, indicating a mesotrophic condition. The ranges of the Shannon-Weaver diversity and Pielou evenness indices of the phytoplankton community were, respectively, 1.12-1.89 and0.38-0.72, indicating light to medium pollution. A total of 54 phytoplankton genera from 7 families were identified during the investigation, dominated by Chlorophyta and Cryptophyta in January and April, and Cyanophyta from May to December. Copepods dominated the zooplankton community in May, September,and October, while rotifers dominated the community in other months. Compared with data from 2017 to2019, the trophic level and phytoplankton abundance of Houguan Lake significantly decreased in 2020,while the proportion of macrozooplankton in the zooplankton community significantly increased. Spearman correlation analysis and redundancy analysis showed that the main driving factors affecting the phytoplankton community of Houguan Lake were water temperature, transparency, and zooplankton abundance. Strengthening of environmental management and reduced human activity in the catchment due to COVID-19 could explain the environmental quality improvement in Houguan Lake in 2020.