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应用底栖藻类群落评价小水电对河流生态系统的影响-以香溪河为例
Alternative TitleUsing benthic algal communities to assess the impacts of small hydropowers on river ecosystem- a case study of Xiangxi River
吴乃成
Subtype硕士
Thesis Advisor蔡庆华
2007-06-13
Degree Grantor中国科学院水生生物研究所
Place of Conferral水生生物研究所
Keyword小水电站 梯级开发 底栖藻类 香溪河 基于底栖藻类的小水电干扰指数 评价 建前-建后-参照-受损
Abstract为探讨小水电开发对河流生态系统的影响,本论文以香溪河为例,用底栖藻类为指示生物,比较了小水电建设前后底栖藻类群落的变化情况;构建了小水电干扰指数,用以评价小水电梯级开发对河流底栖藻类的影响;研究了小水电开发在不同月份对底栖藻类的影响。主要结果如下: 1.选择香溪河一支流—九冲河上一个电站(芦院电站,于2003年8月投入生产),依据“建前-建后-参照-受损 (BACI)”的设计方法,从2003年2月~2004年8月对底栖藻类进行月度采样。共观测到底栖藻类130种(变种),分属硅藻(107种)、绿藻(11种)和蓝藻(12种)三门,计40个属。硅藻为绝对优势类群,相对丰富度为69.81%。分析表明,电站建设后,取水坝下游样点的流速、水深、水面宽度等主要物理指标变化显著,而其它化学指标(NH4-N、TN、SiO2等)不受电站建设的影响;从底栖藻类群落整体来说(通过非度量多维标度分析),在小水电建设后的一年内,对底栖藻类群落的影响不明显(MRPP分析,p>0.05),但对5项藻类评价参数的影响显著(如桥弯藻属密度、直立型相对含量、硅藻总密度、物种丰富度及Margalef多样性指数)。 2.为探讨小水电梯级开发对底栖藻类群落的影响,于2005年10月20日至11月1日分别对香溪河流域内23个小水电站(每个电站设立5个采样点,样点1、2位于出水口上游,样点3位于取水坝下游,样点4、5分别处于出水口的上下游)共92个样点及未受电站干扰的4个样点(R1-R4)进行采样分析。共观察到底栖藻类150种,分属硅藻(133种)、绿藻(8种)和蓝藻(9种)三门,计38个属。硅藻为绝对优势类群,相对丰富度为78.05%,其中,线形曲壳藻(Achnanthes linearis)和扁圆卵形藻(Cocconeis placentula)为绝对优势种,平均相对丰富度分别为60.82%和10.22%。 据其所处生境不同所有采样点可分为5组,第一组是参照点包括R1-R4及每个电站的1号样点(共24个);第二组为每个电站的2号样点(共19个);第三组为每个电站的3号样点(共21个);第四组为每个电站的4号样点(共15个);第五组为每个电站的5号样点(共15个)。比较各组理化指标,发现流速等物理因素是小水电开发对河流生态系统的主要影响因素。与此同时,从91个底栖藻类群落候选参数中选取了7项核心参数,包括藻类叶绿素a浓度、3种优势属的密度(曲壳藻属、桥弯藻属、舟形藻属)、卵形藻属百分含量、Margalef多样性指数和硅藻物种丰富度用来构建小水电干扰指数。该指数能很好地反映小水电梯级开发对河流生态系统的影响。结果表明,受影响最严重的是位于取水口和出水口之间的河段。 3.为研究小水电在不同月份对河流底栖藻类的影响,从2005年11月至2006年6月份,对香溪河干流上一个典型电站(苍坪河电站)进行月度监测。共观察到底栖藻类119种,分属硅藻(104种)、绿藻(6种)和蓝藻(9种)三门,计32个属。硅藻仍占绝对优势,相对丰富度为61.90%。双因素方差(Two-way ANOVA)分析表明:流速、水面宽度、水深、电导率和总溶解性固体在时间和空间尺度上差异均显著(p<0.05),而pH、浊度、溶解氧、水温和氧化还原电位只在时间尺度上变化显著(p<0.05)。 采用小水电干扰指数来评价电站取水对河流生态系统的影响,将设置的所有样点分成三组(G1-G3):G1组样点位于电站取水口上游,G2组样点位于取水口和出水口之间,G3样点位于出水口下游。三组样点的小水电干扰指数得分均存在明显的季节波动(F分别为11.24、17.14、40.35,p均<0.0001)。如果按75分以上为“很好”、50-75为“好”、25-50为“一般”、25以下为“差”作为评价的标准,则第一组样点(G1)除2005年11月和2006年6月为“好”外,均为“很好”;第二组样点(G2),从2005年11月至2006年3月有逐步变好的趋势(从“一般”到“很好”),从2006年3月后又有降低趋势;第三组样点(G3)除2005年11月为“一般”外,均为“好”或“很好”。从2005年11月至2006年2月,小水电干扰指数得分在三组样点间差异显著(F分别为:10.18、17.51、8.18、6.53,p均<0.05);而从2006年3至6月差异不显著(p均>0.05);在2005年11月和2006年6月,三组样点的得分值均较低,处于“好”和“一般”之间。 小水电取水对河流生态系统的影响因干旱持续长短而异:即使在丰水期,只要断流时间足够长(如2006年6月份),就会对河流底栖藻类产生影响。反之,即使在枯水期只要保证河流周期性的连通,也不会对底栖藻类产生较大影响。
Other AbstractIn order to explore the impacts of the small hydropowers (SHPs) on the river ecosystem, several researches based on benthic algae were carried out in Xiangxi River: 1) Changes of benthic algal communities following a low-head dam construction. 2) Developing a benthic algae based Index of SHP’s Disturbance (B-ISHD) to assess the influence of the cascade small hydropowers on benthic algal communities in Xiangxi River system. 3) Effects of a small hydropower on benthic algal communities in different months. The main results are as follows: 1. We chose a small hydropower station (named Luyuan hydropower station, run in August 2003), which is located on a tributary of Xiangxi River. Monthly sampling of 5 sites (JC09, JC08, JC05, JC03 and JC02) was carried out from February 2003 to August 2004 and a modified ‘Before-After-Control- Impact’ (BACI) was used to study the responses of benthic algal communities downstream of the dam. Benthic algal sampling yielded 130 taxa (mostly to species levels) in 40 genera, which belonged to Bacillariophyta (107 taxa), Chlorophyta (11 taxa) and Cyanophyta (12 taxa), and diatoms were predominant with 69.81 % of the total taxa. Results indicated that some physical factors (flow velocity, depth and channel width) and 5 algal metrics (including the density of Cymbella individuals, % erect individuals, total density of diatoms, richness and Margalef diversity) were significantly affected by SHP, while other chemical factors (NH4-N, TN, SiO2, etc.) were not influenced. However, overall assemblage structure downstream remained similar to upstream control sites throughout the study by means of Non-metric Multidimensional Scaling ordinations (MRPP, p>0.05). 2. In order to explore the impacts of the cascade development of small hydropowers on the river ecosystem, a total of 92 sites of 23 SHPs (5 sites were placed on each SHP, and site1 is located at 100m upstream the dam which formed by intake of SHP, site2 just upstream the dam, site3 just downstream the dam, site4 is about 50m upstream the SHP’s outlet, while site5 is mounted at outlet of SHP) within Xiangxi River and other 4 reference sites (R1-R4) were sampled from October 20 to November 1, 2005. Periphyton sampling yielded 150 taxa (mostly to species levels) in 38 genera, which belonged to Bacillariophyta (133 taxa), Chlorophyta (8 taxa) and Cyanophyta (9 taxa), and diatoms were predominant with 78.05 % of the total taxa. Achnanthes linearis and Cocconeis placentula were the most abundant species, whose relative abundances were 60.82 % and 10.22 %, respectively. All the sites were divided into 5 groups based on their habitats. Group 1 was reference group including R1-R4 and site 1 of all SHPs; all SHPs’ site 2 to 5 made up of Group 2 to 5, respectively. Then, we tried to comparing differences of physicochemical factors among them by one-way ANOVA, and the results indicated that physical factors (flow velocity) were the main factor affecting the aquatic ecosystem. 91 potential attributes belonging to 13 categories were selected originally. Based on the selection methods, final 7 attributes (Chl a, the densities of 3 dominant genera, % Cocconeis individuals, Margalef diversity and richness) were selected to develop a benthic algae based Index of SHP’s Disturbance (B-ISHD). Based on B-ISHD, we found that segment between the dam and the outlet was severely influenced by SHPs. 3. In order to study the temporal impacts of SHP on benthic algal communities, we chose a typical station (Cangpinghe hydropower station) and carried out monthly sampling from November 2005 to June 2006. A total of 119 taxa (mostly to species levels) in 32 genera were identified, which belonged to Bacillariophyta (104 taxa), Chlorophyta (6 taxa) and Cyanophyta (9 taxa), and diatoms were also predominant with 61.90 % of the total taxa. Two-way ANOVA indicated that water flow velocity, width and depth were significantly different among not only different sampling dates but also sampling locations (p<0.05), while pH, turbidity (TURB), dissovled oxygen (DO), water temperature (WT) and ORP were only different among different sampling date (p<0.05). Benthic algae based Index of SHP’s Disturbance (B-ISHD) was employed to assess the impacts of water abstractions on river ecosystem. All the sites were divided into 3 groups (G1-G3). Sites located upstream of dam were sorted into G1, and G2 included the sites between the dam and the outlet while sites downstream the outlet made up of G3. B-ISHD scores of three groups (G1-G3) showed a remarkable seasonal fluctuation (F values were 11.24, 17.14, 40.35, respectively and all the p values <0.0001). We set standard as: >75: excellence, 50-74: good, 49-25: fair, <24: poor, then, apart from November and June, which were good, all the B-ISHD scores of first group 1 (G1) are excellence; the B-ISHD scores of group 2 (G2) varied dramatically–from November 2005 to March 2006 it increased gradually (from fair to good) and then decreased until June 2006; the B-ISHD scores of group 3 (G3) were good or excellence except for November (fair). During the first 4-month sampling period, B-ISHD scores were significantly different among three groups (F values were 10.18, 17.51, 8.18 and 6.53, respectively; all the p values <0.05), but from March to June 2006 were not (all the p values >0.05). B-ISHD scores of two sampling occasions (November and June) were relative lower than others, which ranged between good and fair. The impacts of water abstractions on benthic algal communities were determined by the duration of drought. Even though in rainy seasons, the influences induced by SHPs on algal communities would be significant if the duration of drought was long enough (e.g. June 2006). On the other hand, if we kept connective of downstream and upstream reaches in dry seasons, impacts on algal communities of SHPs could also be ignored.
Pages103
Language中文
Document Type学位论文
Identifierhttp://ir.ihb.ac.cn/handle/342005/12192
Collection学位论文
Recommended Citation
GB/T 7714
吴乃成. 应用底栖藻类群落评价小水电对河流生态系统的影响-以香溪河为例[D]. 水生生物研究所. 中国科学院水生生物研究所,2007.
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