【作者】 沈忱；

【导师】 刘茂松；

【作者基本信息】 南京大学 ， 生态学， 2012， 硕士

【摘要】 湖滨带是连接湖泊水域生态系统与陆地生态系统的功能过渡区,是湖泊生产力、生境多样性和生物多样性最集中的区域,在涵养水源、净化水体、维护生物多样性和保持生态平衡等方面有重要的作用。随着工农业发展、人口增长以及人类不合理开发活动的加剧,越来越多的湖滨带结构、生态过程受到干扰和破坏,生态功能下降,外在表现为生物多样性下降及自然景观的退化,湖滨带生态修复成为湖泊生态治理的重要措施。其主要措施包括生境修复、群落结构修复和生态系统功能修复3个方面。可通过基底修复、选择适宜的先锋植物和群落结构配置,实行水体、底泥、植被与群落同步分级恢复,逐步使湖滨带生态系统的结构、功能和生态学潜力恢复到原有水平。大型底栖动物是水生态系统食物链中重要组成部分,其优势类群主要包括水栖寡毛类、软体动物和水生昆虫等,在加速碎屑分解,调节泥水界面物质交换,促进水体自净等方面具有重要作用。由于底栖动物寿命较长,迁移能力有限,对环境变化反应敏感,因此,当水体富营养化或受到污染时,底栖动物群落结构及多样性会发生明显改变,而河流湖泊的底质、水环境等生境差异也会对底栖动物的分布造成影响。太湖贡湖湾生态修复工程区是国家林业局太湖治理湿地生态保护与恢复工程的一个工程点,于2008年11月竣工,面积约0.2km2,北接湖岸,南面由留有缺口的几段低浅人工桩基消浪堰与太湖相接,形成了一个东西向长约1100m、南北宽约160m的半封闭型的矩形人工湖湾。其生态修复工程已实施近四年,其消浪堰内、外形成了3个不同生境梯度,为研究工程区内底栖动物的分布状况、群落结构及其与水质指标等的相互关系,于2010年-2011年调查了修复区内几种典型生境梯度内的底栖动物种类和密度,并且同步调查了各梯度带的水质状况,对底栖动物群落和水质状况之间的关系做了研究,结果表明：(1)修复工程的实施使得消浪堰内、外形成了3个不同生境梯度,即滨岸挺水植物带、湾相沉水植物带、堰外开敞水体,分别记为Ⅰ带、Ⅱ带和Ⅲ带。不同生境梯度的底栖动物在物种组成和群落结构上均存在差异。底栖动物种类数量为Ⅲ带>Ⅰ带>Ⅱ带,种群密度为Ⅲ带>Ⅱ带>Ⅰ带,消浪堰内的底栖动物种类数和密度均低于堰外。3个生境梯度带均有物种仅出现于相应的生境梯度带中,且共有12个物种的种群密度存在生境梯度间差异,占总物种数的66.7%；(2)从摄食功能类群来看,刮食者和收集者在工程区内是优势类群,其中刮食者在Ⅰ带和Ⅲ带相对丰度较高,在Ⅱ带相对丰富最低；收集者在Ⅱ带种数最少,相对丰度最高；滤食者在Ⅰ带相对丰度最低,仅出现与该生境梯度的种类数最少；从生活类群来看,物种数和相对丰度的GS/GSB均为Ⅰ带最高,Ⅱ带最低；(3)工程区水质状况是影响底栖动物群落分布的重要环境因素,DO、TN、 NH4-N、NO2-N、NO3-N、TP、PO4-P、COD等8个水质参数共可以解释54.5%的底栖动物群落的结构差异。其中DO以及N、P元素动态是最关键的影响因子,工程区大多数底栖动物群落分布均与其密切相关。环节类和昆虫与DO呈正相关,对水体富营养化耐受能力较强,而软体动物大多与水体富营养化程度负相关,一些运动能力较强的腹足类对于低DO环境的耐受能力较强,在还原性较强的区域有较多分布。本文通过在对工程区内底栖动物群落状况调查,发现了底栖动物在不同生境梯度下的分布状况；同时通过研究底栖动物群落状况与水质之间的关系,揭示了不同类群底栖动物对于不同水质因子的响应。研究结果在一定程度上揭示了滨岸带生态修复区内底栖动物与环境间的关系,可为湖滨带生态修复工程的设计与建设提供参考。更多还原

【Abstract】 As a kind of aquatic-terrestrial ecotone, riparian area plays an important role in the lake basin ecosystem, and has high ecological, social and economic values. Its functions include lake buffer, conservation of biological diversities and special habitats, dike protection from soil erosion, and economic and esthetics values. The main factors inducting riparian area degradation are the anthropogenic activities that caused the converse succession of communities and the decline of ecological function. The theoretical basis of ecological restoration and reconstruction of degraded riparian area is restoration ecology; while the technologies are of three types, i. e., habitat restoration and reconstruction, species restoration and reconstruction, and structural and functional restoration.Macrobenthos is an important component of wetland ecosystems. Auatic Oligochaetes, mollusks and aquatic insects are the dominant groups of macrobenthos in freshwater. Macrobenthos in freshwater plays an important role in accelerating debris decomposition, regulating the material exchange on the interface water, and the promotion of self-purification of water. Macrobenthos is sensitive to the variation habitat due to the limited migration ability and the comparative long life. The distribution of macrobenthos will change significantly with different sediments of rivers and lakes, water environments and habitats. It has great significance to understand the structure, function and evolution of wetland ecosystems. Current researched had no enough attention on relationship between the macrobenthos composition and the habitat in ecological restoration pilot area. In this study, The T-Park ecological restoration project zone was taken as the study area. We wanted to study the macrobenthos composition, the habitat gradient, and the relationships between them, which had an important reference value on researches on the ecological restoration engineering.To examine the relationships between habitat gradient and macrobenthos composition, a field investigation was undertaken in three different habitats, riparian zone with emerged vegetation (zone Ⅰ), lake-bay zone with submerged vegetation (zone Ⅱ) and open water zone outside the weir (zone Ⅲ) in an ecological restoration pilot area of Gonghu Bay, Taihu Lake, during2010-2011. The result shows:(1) Collectively,18species of macrobenthos were identified from12sampling sites. Of those,7species were found in association with only one habitat type. Of the other11species,5ones showed significant differences in abundance across the habitat gradient.(2) By investigating the distribution of functional feeding groups of macrobenthos, significant differences were observed among the habitat types. For the scrapers, the highest relative abundance was shown in zone I, while that was present in zone II and III for gather-collectors and filter-collectors, respectively. In terms of species richness and relative abundance, the ratio between group of surface and group of surface below (GS/GSB) were the highest in zone I and the lowest in zone II.(3) Redundancy analysis was applied to examine the influence of water quality on macrobenthos composition. The results showed that annelids and aquatic insects were positively correlated with DO, NO3--N, PO43--P. Mollusks were negatively correlated with NO3--N and PO43--P. Some mollusks were able to endure the stress from low DO and correlated positively with NH4+-N and COD.Overall, the three distinctive habitat types were formed via the restoration project and varied in hydraulic conditions, water quality and substrates. As a result, they can lead to three different types of macrobenthos in terms of life form and feeding attributes.This study identified macrobenthos composition in three different habitats in an ecological restoration pilot area of Gonghu Bay, Taihu Lake; while by investigating distribution of functional feeding groups and life groups of the macrobenthos, revealed the communities difference among the three habitats. Redundancy analysis in the relationships between habitat gradient and macrobenthos composition showed the three distinctive habitat types lead to three different types of macrobenthos in terms of life form and feeding attributes. The results could provide a reference for protection on ecological restoration and reconstruction of degraded riparian area.更多还原