【作者】 王强；

【导师】 袁兴中；

【作者基本信息】 重庆大学 ， 环境科学， 2011， 博士

【摘要】 河流生境是河流生物和物理环境的自然联系,受到河道内部结构、流域地形地貌、人为干扰等环境因素影响。大型底栖动物和鱼类是山地河流生态系统的重要组成部分,对河流生境的变化最为敏感。近年来为了片面追求经济效益,引水式小水电建设造成山地河流流域生态失调,坝下河段减水、脱水甚至河床干涸,河流生境破碎和衰退,水生生物多样性丧失等日益严重的生态环境问题。如何寻求水能资源开发与山地河流生态系统健康、河流生物多样性完整的和谐发展,是急需研究和探索的重大问题。基于我国山地河流的环境现状和现实需要,本研究紧紧围绕河流生境这一研究主题,开展宏观、中观、微观尺度的山地河流生境分类研究,从中观和微观尺度研究山地河流生境对大型底栖动物的影响,研究了引水式小水电影响下河流生境演变规律及大型底栖动物和鱼类的响应机制。主要研究结论如下:(1)基于Bisson的河流生境分类方法,结合野外实地调查和GIS分析,以地处三峡库区腹心的重庆开县东河为研究对象,开展宏观、中观、微观尺度的山地河流生境分类研究。在河流系统尺度上,将东河划分为上游、中游、下游3段;河区尺度上,将东河河流生境划分为源头河区、基岩河区、淤积河区三种类型;在河段尺度上,划分了源头河段、基岩河段、小瀑布河段、深潭-浅滩河段、阶梯-深潭河段、平坦河床河段6种类型;河道生境单元尺度上,划分了跌水、小瀑布、急濑、浅濑、斜槽、平流、回水潭、深沟、河道中央水潭、侧面冲槽、跌水潭、崩塌阻塞水潭、死水潭、二级河道水潭等14种类型。微生境尺度上,按照河床底质颗粒大小划分了河流生境。(2)调查了重庆市城口县鱼肚河源头河段小圆石和大圆石上附石性水生昆虫,研究了山地源头溪流附石性水生昆虫群落特征和多样性,探讨了不同大小石块对附石性水生昆虫群落的影响。结果表明:鱼肚河源头溪流中水生昆虫有62种,分属6目、30科。蜉蝣目、毛翅目、双翅目昆虫为优势类群。随着溪流高程的增加,毛翅目昆虫优势度愈加明显。附石性水生昆虫功能摄食类群以撕食者、收集者为主。大圆石上附石性水生昆虫群落多度、Shannon-Wiener多样性指数、Margalef丰度指数显著高于小圆石。沿溪流高程梯度,小圆石上水生昆虫群落多样性指标无显著差异;大圆石上水生昆虫群落多度、Margalef丰度指数有显著差异。两种石块在生境异质性和稳定性上的差异是附石性水生昆虫群落差异的主要原因。(3)浅滩和深潭是山地河流中观尺度上常见的河流生境结构。在重庆开县东河上游双河口-杉木桥河段,选择21个浅滩和深潭,调查大型底栖动物。结果表明:调查河段浅滩和深潭中大型底栖动物分别为31种和24种,密度分别为450.62 ind/m~2和86.24 ind/m~2,生物量分别为2.88 g/m~2和0.55 g/m~2。浅滩有指示种11种,即纹石蛾、假蜉、假二翅蜉、舌石蛾、高翔蜉、背刺蜉、Heterocloeon sp、锯形蜉、朝大蚊、等蜉、溪颏蜉。深潭指示种仅蜉蝣和黑大蚊两种。刮食者为两类生境的优势功能摄食类群。浅滩中滤食者和刮食者比例显著高于深潭,而收集者和捕食者显著低于深潭。两类生境中大型底栖动物群落结构差异显著。浅滩中大型底栖动物的密度、生物量、丰富度指数、Shannon-Wiener指数、改进的Shannon-Wiener指数均明显高于深潭。受地貌形态、水力特征和冲淤变化规律影响的生境稳定性和异质性差异是大型底栖动物群落差异的主要原因。(4)调查重庆东河白里电站和红花电站影响河段的河流生境和鱼类,研究引水式小水电对山地河流鱼类群落的影响,从河流生境角度对其影响机制进行探讨。共采集鱼类149尾,隶属4目、8科、16属、17种。研究表明,引水式小水电影响河段鱼类多样性普遍偏低。引水坝修建后,库区逐年淤积,河流生境异质性和多样性丧失;坝下形成减水河段,河流生境面积缩小,浅滩-深潭交替的生境结构被破坏。引水式小水电对鱼类群落的影响主要是引水坝修建改变河流生境所致。(5)选择重庆东河白里电站和红花电站影响河段为研究区域,各电站设置库尾以上河段,库区河段,引水坝下减水河段,电站出水口以上河段,电站出水口以下河段5个调查河段,研究引水式小水电对河流大型底栖动物群落的影响。调查共采集到大型底栖动物43种,隶属3门4纲30科。各调查河段大型底栖动物组成以蜉蝣目、毛翅目昆虫为主。研究表明,引水式小水电修建后河流水质并未发生明显变化,但库区河段和坝下河段的生境状况发生了较大变化。库区河段受泥沙淤积影响,依然保持流水状态,大型底栖动物与电站出水口及库区河段无明显差异。但是由于泥沙淤积降低了生境的多样性和异质性,库区河段大型底栖动物群落密度、生物量和多样性指数显著低于电站出水口以下河段。坝下河段由于流量减少,生境适宜性降低,大型底栖动物密度、生物量和多样性明显降低。(6)从河流生境结构和功能出发,选用河流生境多样性指数、河道湿润率、生境单元质量指数,采用专家打分法确定权重系数,建立了山地河流生境快速评价指标体系及定量评价模型。选取东河进行河流生境质量定量评价。结果表明河流生境质量从库尾以上河段起逐步下降,在引水坝以下河段降至最低,其后呈逐渐恢复的态势。坝下河流生境主要受到河流减水影响;坝上河段河流生境主要受泥沙淤积影响。评价结果能较直观地反映水电工程影响下山地河流生境状况,以及导致河流生境质量衰退的原因。更多还原

【Abstract】 River habitat was significant influenced by in stream physical structure, topography, geomorphology and human disturbance and was also important to river biodiversity. Macroinvertebrate and fish, which is sensitive to river habitat variation, were important component of mountain river ecosystem. In the past twenties years, numerous small diversion type hydropower stations were constructed in mountain river of China for their good economic benefit. As a consequence, a lot of environmental problem relative to river ecosystem and aquatic organisms exhibited including dysbiosis, drought of river channel, habitat fragmentation and loss of aquatic biodiversity. Therefore, maintenance of mountain river ecosystem health, biodiversity integrity was important and urgent for water energy resource exploitation in China.In view of the need of reality and present environment status of mountain river in China, we conducted research on river habitat. In this study, we classified river habitat of mountain river ranging from macro to meso and micro habitat scale, explored the relationship between macroinvertebrate and meso habitat and micro habitat, discovered both character of river habitat and pattern of macroinvertebrate and fish community diversity which were influenced by small diversion type hydropower stations.The main contents and researeh results are summarized as follows:(1) According to Bisson’s river habitat classification system and basing and based on GIS technology and field survey date, we classified river habitat of Dong River ranging from macro to meso and micro habitat scale. At river system scale, we divided Dong River in to three parts, including upstream, middlestream and downstream. At river segment scale, we identified three types segment, including colluvial valleys, bedrock valleys, headwear valleys. At river reach scale, six types of river reaches presented in Dong River, including bedrock reaches, headwear reaches, cascade reaches, step-pool reaches, plane-bed reaches, pool-riffle reaches. At channel unit scale, Dong River had 14 types of habitat as followings: falls, cascade, rapids, riffle, chute, run, eddy, trench, midchannel pool, latteral pool, plunge pool, landslide dam pool, backwater and abandoned channel pool. River habitat at micro habitat scale can be classified according to substrate particle size.(2) Aquatic insect larva on stone surfaces played an important role in headwater ecosystem. In May 2007, aquatic insect larvas on small and large cobble surface in four sampling section were investigated in the headwater of Yudu stream in Chengkou County, Chongqing. The aim of present research is to discover the community characteristic and biodiversity of aquatic insect on stone surface and analyze the influence of stone size on insect larva. The result shows that there were 62 species of 30 families of 8 orders in headwater of Yundu stream. Ephemeroptera, Trichoptera and Diptera were the dominant groups. Trichoptera showed more proportions in stream reach of higher altitude. Shredder and Collector-gatherer were dominant functional feeding groups. Abundance, Shannon-Wiener Index and Margalef index of large cobble were significantly higher than that of small cobble, which may be determined by heterogeneity and stability difference of these two types of stone habitats. There were no significant differences in biodiversity index of aquatic insect larva on small cobble among four sampling sites, while abundance and Margalef Index of larva on large cobble were significant different.(3) Riffle and pool was the most common habitat unit in mountain river. In July 2011, macroinvertebrate of twenty one riffles and pools respectively in upstream of Dong River in Kaixian County of Chongqing were sampling to compare their difference in assemblage structure and composition. The result indicated that there were 31 and 24 in riffles and pools respectively. The density, wet biomass of riffles were 450.62 ind/m~2 and 2.88 g/m~2, respectively, compared to 86.24 ind/m~2 and 0.55 g/m~2 of pools. Eleven taxon, including Hydropsyche sp, Iron sp, Pseudocloeon sp, Glossosoma sp, Epeorus sp2, Notacanthurus sp, Heterocloeon sp, Serratella sp, Antocha sp, Isonychia sp and Rhithrogena sp, were indicator species of riffles, while pools only had two indicator species, Ephemera sp and Hexatoma sp. Scraper was the dominate functional feeding group in both habitat. Riffles exhibited significantly higher percentage of collector-filterer and scraper, while percentage of collector-gatherer and predator in pools were significantly higher than that of riffles. Difference of macroinvertebrate community structure among two habitats was significant. Density, biomass, species richness, Shannon-Wiener index and Improved Shannon-Wiener index of riffles were significant higher than that of pools. Habitat stability and heterogeneity affected by habitat morphology, hydraulic characteristics and erosion/deposition pattern may be the major explanation.(4) Stream habitat and fish community of Dong River in Chongqing were investigated in order to explore the impact of two small diversion type hydropower station, Baili station and Honghua station. Mechanism of their influence on fish community was analysis from stream habitat angle. One hundred and forty-nine fishes were collected in our survey, which were subordinate to seventeen species, sixteen genus, eight families and four orders. The result showed that biodiversity of fish community of the river reach influenced by small diversion type hydropower station was rather lower and the stations was an important reason to explain depressing of fish biodiversity in mountainous stream. After the construction of water dam, habitat heterogeneity and diversity of reservoir area was lost as a result of sediment deposition. Habitat area for fish in reach between dam and powerhouse was decreased and riffle-pool structure was destructed as a result of water regime alteration. Small diversion type hydropower station influenced fish community mainly by deterioration of stream habitat.(5) Macroinvertebrate in river reaches influenced by two small diversion type hydropower stations on Dong River, namely Baili and Honghua, were sampling to explore their influence. The result indicated that there were 43 species belonging to three phylum, four classes and thirty families. Mayfly and caddify were the dominated taxa. Water quality was not significant changed by small diversion type hydropower stations, while river habitat deteriorated a lot. The reach behind the dam was influenced by sediment deposition and the flow pattern here was lotic. Component of macroinvertebrate community in the reach behind the dam were not significantly different from the reach disaffected by dam, but density, biodiversity and biomass were significantly depressed. Habitat suitability of the reach downstream of the dam was declined by flux decreasing and macroinvertebrate here exhibited lower density, biodiversity and biomass.(6) An evaluation model was established originated from both stream ecosystem structure and function integrality. This model was composed by an index system including stream habitat diversity indicator, channel wet rate and habitat unit quality indicator for rapid habitat quantificational assessment. The weight of indicators was determined by means of Delphi method. The model was used to assess the stream habitat quality of the Dong River which located in the Three Gorges region and influenced by hydroelectric projects. The results show that the habitat quality of the segment behind the dam is worse than the segment both in front of the dam and behind the hydroelectric plant water outlet. Lack of river ecological basic flow should be responsible for the worse status of the segment behind the dam and sediment deposition depressed the status of stream habitat in front of dam. Results of the evaluation can more directly reflect the status of habitat in mountain streams under the influence of hydropower projects, and the reasons of their deterioration.更多还原