【作者】 黄玉洁；

【导师】 张银龙；

【作者基本信息】 南京林业大学 ， 生态学， 2011， 博士

【摘要】 竺山湾河口湿地是太湖水域第一块建成的规模化河口湿地,其背靠太湖,又位于太滆运河河口,受太湖、滆湖和太滆运河影响,地理位置特殊,生境独特,同时还受到很多外界的干扰和破坏。因此,其建设、研究成果对太湖其它河口湿地、湖滨带以及同类浅水湖泊湿地恢复都具有普遍指导意义。本文以竺山湾湿地植被恢复区为研究区,研究了恢复后湿地植物的群落特征、沉积物粒度、沉积物中碳、氮、磷的分布特征以及重金属污染状况,为评价湿地植被建设成果、完善湿地生态修复技术和管理方案及后期湿地恢复的长期监测和研究提供了基础数据和科学依据。主要研究结果如下：(1)恢复后的湿地植物群落发展正处于上升阶段,并已进入自然演替状态,但整体生物量还偏低,生态系统的生产力水平还有待于进一步提高。不同水分条件对物种多样性变化影响较大,随着基底高程的降低,物种丰富度指数呈下降趋势,Shannon-Wiener多样性指数和Pielou均匀度指数变化基本一致,先降低后升高,Simpson优势度指数则先升高后降低。(2)研究区沉积物组成以粉砂为主,沉积物类型主要是砂质粉砂和粉砂。粘土、粉砂、砂均为中等程度变异,且在研究区分布比较均匀。芦苇群落对沉积物中粘粒和砂粒的沉积效果最好。(3)沉积物有机碳的平均值为19.59g·kg-1,储量较高；全氮含量不是很高,平均值为1.25g·kg-1,全磷和有效磷的平均值分别为5.32g·kg-1和420mg·kg-1,其中全磷的平均值远超过加拿大安大略省环境和能源部发布的沉积物严重级别生态毒性效应的全磷浓度。从不同群落来看,总体上芦苇群落对碳、氮、磷等元素的拦截、沉积效果最好；沉水植物群落和芦苇群落分布区中大部分区域碳氮比都大于20,表明研究区有机质的外源输入量很大。(4)有机碳、全氮、全磷和有效磷的季节变化顺序都为秋冬季>春季>夏季,其主要受温度、水环境、湿地动植物、微生物等因素变化的影响。对植物体内氮、磷含量的研究表明单位面积内芦苇的全氮贮量是香蒲的6.65倍,全磷贮量是荷花的4.41倍,因此芦苇是研究区高功能积累群落。(5)沉积物中As、Cd、Gr、Cu、Ni、Pb、Zn七种重金属的平均值都明显高于各自的背景值。地累积指数法评价结果显示,研究区As、Cd的污染程度比较严重,Zn的污染基本上为中等程度,Cr、Pb基本上为轻微污染。潜在生态风险指数法评价显示,研究区大约80%的区域处于强与很强的危害程度,造成研究区重金属潜在危害的主要元素是Cd和As。更多还原

【Abstract】 Zhushan Bay wetland was the first estuary designed as restoration wetland in Taihu lake. It was located adjacent to Taihu lake and close to estuary of Taige canal thus can be influenced by Taihu lake, Gehu lake and Taige canal. The area receive high levels of human the disturbances and destructions. A case study on the wetland plant restoring area of Zhushan Bay was conducted to reveal the characteristics of the wetland plant community, grain size of the sediments, spatial distribution of C, N, P and the pollution condition of heavy metals in the sediments. The results showed:(1) The restored wetland plant community was in early succession stage. The overall plant biomass was low. Ecosystem productivity was positioned to increase. Water depth showed great influence on the species diversity. Plant species richness index reduced, Shannon-wiener diversity index and Pielou evenness index first decreased then increased, while Simpson dominance index first increased then decreased along increase with water depth.(2) In the studied area, the sediments was primarily consisted of silt. Dominant sediments were mainly silt and sandy silt. The clay, silt and sand all had moderate variability and were well-distributed in the space. Deposition of the clay and sand was the highest in Phragmites australis community.(3) SOC was very high with a mean value of 19.59g·kg-1. TN was relatively low with a mean vaule of 1.25g·kg-1. The means of TP, AP were 5.32g·kg-1 and 420mg·kg-1 respectively. The mean of TP greatly exceed levels of toxic tolerance standards issued by Environment and Energy Ministry of Ontario, Canada. From the different community, Phragmites australis community intercepted the highest levels of sediment and C, N, P. Sediment C/N was greater than 20 in most submerged plant community and Phragmites australis community, which showed exogenous input of organic matters.(4) Seasonal changes of SOC, TN, TP and AP all were autumn-winter spring>summer mainly influenced by change of the temperature, water environment, the wetland plants, animals and microbes. In the same area TN of Phragmites australis was 6.65 times that of Typha angustifolia. TP of Phragmites australis was 4.41 times that of Nelumbo nucifera. Phragmites australis community was most effective in intercepting sediments and elements.(5) The average contents of As, Cd, Cr, Cu, Ni, Pb and Zn were all higher than their background values. Results from Geo-accumulation index method indicated that As and Cd reached the serious pollution level, that Zn was the moderate pollution level, that Cr and Pb reached the lower pollution level, that Cu and Ni pollution had different pollution levels in the studied area. Results from ecological risk index method indicated that about 80% of the studied area reached severe and very severe harm degree and Cd and As were the main elements of potential harm.更多还原