【作者】 李然然；

【导师】 章光新；

【作者基本信息】 中国科学院研究生院（东北地理与农业生态研究所） ， 环境科学， 2014， 博士

【摘要】 湿地水环境是湿地生态系统的重要组成部分，也是导致湿地形成、发展、演替、消亡与再生的关键因素。全球气候变化与高强度人类活动导致湿地水位、水流和水质等水环境恶化，给湿地生态系统结构稳定和功能发挥带来潜在风险。本文以吉林西部重要的生态屏障——查干湖湿地为研究对象，重点研究了查干湖湿地水位、水质演变特征及规律，运用多元统计分析方法分析浮游生物与环境因子的关系，在此基础上，建立了查干湖湿地生态风险评价指标体系，定量评估其生态风险并进行了等级分区，提出相应的水环境保护管理对策，对维系查干湖湿地生态系统的稳定与健康具有重要的理论意义和现实意义。通过研究取得以下几个方面主要成果：（1）查干湖湿地水环境演变特征及规律利用1982~2011年的水位资料和1985~2011年的水质资料分析查干湖湿地水环境演变特征，采用卡尔森指数法和模糊综合评价法对查干湖湿地进行综合营养状态和水质状况评价。结果表明引松工程通水后查干湖湿地水位得以恢复并稳定在129.8~130.3m；20世纪80年代末湿地水环境大幅改善，水体盐碱化、富营养化、有机污染得以缓解，但2006年以来水质碱化和有机质污染加剧，水质由Ⅲ类演变为IV类。现阶段农田退水缓解了主湖区的碱化且暂未加剧其富营养化水平。查干湖湿地水质受流域陆源排放、湖泊内源释放及水文情势等多重因素的交互作用，表现为以年为周期的季节变化，呈以磷素为限制的中营养状态。（2）查干湖湿地水环境变化的生态效应调查期间共鉴定出浮游植物5门53属127种，主要由硅藻和绿藻组成；浮游动物4门26属46种，轮虫的种类、丰度均处绝对优势地位。结合聚类（Cluster）、多维排序尺度（MDS）、冗余度分析（RDA）、典范对应关系分析（CCA）以及多样性指数等手段，研究了查干湖湿地2012年平水期（5月）和丰水期（9月）浮游动植物的种群结构特征、丰度、多样性及其与环境因子的关系。研究表明：浮游生物丰度及生物量受盐度、营养盐、流速等的影响，时空差异显著：平水期高于丰水期，新庙泡低于主湖区。浮游植物群落主要受pH值、盐度、PO43-、TN和BOD5影响，浮游动物种群差异来自于pH值、水温、CODMn和BOD5四个环境因子影响。浮游生物多样性结果显示查干湖湿地处于β-中度污染水平。（3）查干湖湿地生态风险评估选取物理化学指标、营养状态指标、有机污染指标及生态指标构成生态风险评价指标体系，基于熵权法研究查干湖湿地2006~2011年生态风险演变特征，并对2012年5月、9月和2013年9月生态风险水平进行空间分级。结果显示：查干湖湿地2006~2011年水环境质量恶化严重，其所面临生态风险日趋严峻，处于中度生态风险；2012年平水期生态风险较丰水期严重，查干湖主湖区南岸、西部及新庙泡生态风险等级高；2013年丰水期生态系统状况较2012年丰水期稳定，但剔除对水环境生态效应的考虑后，导致单个指标熵权过大，使生态风险评价结果产生两级分化现象。以查干湖湿地生态风险等级划分为依据，提出保护、维持其水环境安全的管理措施。通过保证水源补给、控制面源污染、构建人工湿地及水生态系统工程建设可从控制污染物源头排放，并增加运移过程的吸附、湖体内部生物治理三个方面减轻其生态威胁，降低生态风险。更多还原

【Abstract】 Water environment is an important component of the wetlandecosystem, is also the key factor for wetland formation, development,succession, death and regeneration. Global climate change andhigh-intensitive human activities deteriorate the water environmentthrough changing the water level, water flow and water qualities ofwetlands, bring potential risks to the structure and function of ecosystem.Chagan Lake wetland, the important ecological barrier in west Jilin, wastaken as the research object. Through analyzing of the evolutionalcharacteristics and laws of the water level and qualities in Chagan Lakewetland, combined with the multivariate analysis of the relationshipsbetween the changing environment and the structure, abundance andbiomass of plankton, a reasonable comprehensive index system wasestablished to assess and classify the ecological risk of Chagan Lakewetland. We proposed corresponding protection and managementstrategies of water environment, which has great theoretic and realisticsignificance to maintain the stability and healthy of the ecosystem.Through the above research, we mainly obtained the followingconclusions:(1) Analysis of evolutional characteristics of water environment ofChagan Lake wetlandAnalyzing the evolutional characteristics of the water environmentwill provide a scientific basis for the protection of the water environmentsecurity. The evolvement of water environment was comprehensivelystudied through analyzing the water level data from1982to2011and the water quality data in1985to2011. Carlson trophic state index (TSI) andthe fuzzy comprehensive evaluation method were used to assess theeutrophication level and the water quality. The results showed the waterlevel was recovered and stabilized at129.8-130.3m after the operation ofthe channel transferring water from Songhua river to Chagan Lake. Watersalinization, eutrophication, organic pollution were mitigated and thewater environment improved considerably in the late1980s, but the trendof alkalization and organic pollution has became serious since2006andthe water quality evolved from Ⅲ category to IV category. The trend ofeutrophication has been relieved since2006. Agriculture drainage hasrelieved the water salinization and hasn‘t aggravated the level ofeutrophication in Chagan Lake temporarily. The water quality of ChaganLake is interactive affected by terrestrial emissions in the catchment,endogenous releases and hydrological regimes and exhibits a remarkablephosphorus limited middle nutrition. Sewage and surface runoff pollutionshould be controlled to protect the water environment health.(2) Ecological effects of the changing water environment in ChaganLake wetlandThe study identified a total of127phytoplankton species (belongingto53genera and5phyla, mainly were Bacillariophyta and Chlorophyta)and46zooplankton species (belonging to26genera and4phyla, Rotiferawere in absolute advantage). This study investigated the biodiversity,abundance and community structures of plankton and their relations withenvironmental factors combining field investigations with cluster analysis,multi-dimensional scaling (MDS), redundancy analysis (RDA), canonicalcorrespondence analysis (CCA), and applying diversity indices in ChaganLake during the intermediate (May) and rainy season (September) in2012. Consisting of two connected parts (the main lake body and Xinmiao wetland), Chagan Lake was found to sustain significanttemporal-spatial variations of plankton populations. The abundance ofplankton in the intermediate season was considerably higher than that inthe rainy season. Because plankton abundance and biomass were affectedby salinity, nutrient, flow rate et al., abundance and biomass in Xinmiaowetland was lower than that in the main lake. the Results showedphytoplankton abundance was influenced by pH, water salinity,phosphate (PO3-4), total nitrogen (TN) and5-day biological oxygendemand (BOD5), while pH, water temperature (T), phosphate (PO3-4),whereas salinity, CODMnand BOD5were the key factors influencedzooplankton abundance. When plankton was used as a bio–indicator inwater quality evaluation, the results revealed that water quality in ChaganLake was in β-moderately-polluted category.(3) Ecological risk assessment of Chagan Lake wetlandPhysical and chemical indexes, nutrient state indicators, organicpollution indexes and ecological factors were selected to evaluate theecological risk in Chagan Lake wetland based on entropy weight.Ecological risk evolution characteristics from2006to2011and spatialclassification of ecological risk were analyzed in May and September,2012and in September,2013. The result showed: Chagan Lake wetlandwere facing an increasingly serious ecological risk during2006to2011,belonged to a moderate level risk; the status in intermediate season wasserious than in rainy season,2012. The major risk area distributed in thesouth and west of Chagan Lake besided Xinmiao wetland; the ecologicalcondition in September,2013was much more stable than in September,2012. Altogether ecosystem status in2013from2012, altogether stable,but out of respect for the ecological effect of water environment, leadingto a single index of entropy is too large, leading to the ecological riskassessment results polarized phenomenon. But without any consideration of ecological index, the entropy of a single index was enlarged, which ledto a polarized phenomenon of the ecological risk assessment results.Protection and management strategies of water environment wereproposed according to the ecological risk classification for Chagan Lakewetland, they are the guarantee of the water supply, control of agriculturalnon-point source pollution, construction of artificial wetland and waterecological system. The serious situation of eco-environment will beeffectively improved through controlling pollutant sources, increasing theadsorption during pollutant transport, combining with biologicaltreatment as well.更多还原