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题名: 城市化对河流生态系统的影响研究--以北京市为例
作者: 陈向
学位类别: 博士
答辩日期: 2016-06
授予单位: 中国科学院研究生院
授予地点: 北京
导师: 周伟奇
关键词: 水质 ; Water quality ; 底栖硅藻 ; diatom assamblages ; 土地利用/覆盖 ; land use and land cover ; 多元分析 ; multiple analysis ; 北京 ; Beijing
其他题名: The influence of urbanization on urban stream ecosystem in Beijing, China
学位专业: 生态学
中文摘要:     城市化的快速发展对城市河流水文、水质及水生生物等产生了重大影响。本论文以快速城市化的北京为研究区域,利用水化历史数据和遥感数据,研究了2000年、2005年和   2010年,北京城市、郊区和山区不同区域河流水质的时空变化特征及其与周边土地利用/覆盖类型变化的相关关系。同时,通过采样调查,定量分析了 2014年  5月-11月五环城区内城市上游河道、城市下游河道及山区对照溪流河流水质、底栖硅藻的空间特征,及其在春季、夏季和秋季的季节变化特征,进一步分析了底栖硅藻的时空分布特征与水质的响应关系。主要研究结果和结论如下:
(1)不同流域及城市五环内的河流水质空间差异明显,但时间差异较小。①不同流域中,山区河流水质显著优于城市河流和郊区河流(p<0.05),郊区河流水质最差。②  2000年-2010年,北京市的水质情况整体上逐渐趋好,表现为城市河流和郊区河流的部分水质理化指标的浓度逐年下降,而山区河流部分水质理化指标的浓度有逐年上升的趋势,但不显著。③城市五环内河流水质空间差异较大,城市下游河道水质理化指标浓度显著高于城市上游河道和对照溪流(p<0.05),而后两者浓度差异不显著(p>0.05 )。④对照溪流、城市上游河道和城市下游河道水质指标(如水温、pH等)之间的季节差异不同。其中,对照溪流指标季节变化较大,而城市上游河道和城市下游河道水质季节变化相对较小。
(2)城市河流底栖硅藻组成空间差异明显;相对丰度和多样性指数季节上有变化,但相对较小。①采样点的硅藻种类可以分为对照溪流、城市上游河道及城市下游河道 3个主要类群。其中,对照溪流的主要优势种为Achnanthidium minutissima;城市上游河道的主要优势种为Pseudostaurosira  brevistriata和Staurosira construens  var. venter;城市下游河道的主要优势种为 Nitzschia  palea。主要优势种的变化特征为城市下游河道>对照溪流>城市上游河道。②主要优势种的季节变化特征表现为,A. minutissima和P.  brevistriata均为春季>秋季>夏季;S. construens  var. venter和  N.palea均为春季>夏季>秋季。③硅藻多样性指数种类丰富度(S)、Shannon多样性指数(H‟)、Pielou均匀度(J‟)及   Simpson多样性指数(D‟)的空间差异特征为:对照溪流>城市上游河道>城市下游河道。④不同样区的多样性指数季节变化差异较大。在对照溪流, S、H‟,J‟的季节变化特征为秋季>夏季>春季,而 D‟为秋季>春季>夏季。在城市上游河道,S的季节变化特征为秋季>春季>夏季,H‟及 D‟为夏季>秋季>春季,但 J‟为夏季>春季>秋季。在城市下游河道,硅藻多样性指数的季节变化特征均为秋季>春季>夏季。
(3)土地利用/覆盖与水质之间有较强的相关关系。①不同区域内的土地利用/覆盖类型所占比例差异较大。在河流 100 m到  2000 m的缓冲区范围内,在山区,林地是主要的土地利用/覆盖类型;在城市,建设用地是主要的土地利用/覆盖类型;而在城郊,耕地是主要的土地利用/覆盖类型。②土地利用/覆盖是北京市水质空间差异的重要影响因素。分析表明,林地与水质呈正相关关系,而不透水表面、耕地、水体等均与水质呈负相关关系。草地与水质的关系较为复杂。③土地利用/覆盖类型对河流水质的影响具有明显的尺度效应。在200 m的缓冲区范围内,林地对水质的影响大于其它土地利用/覆盖类型;而在300 m到600 m,林地、建设用地、耕地等均对水质有显著影响;而在 600 m以后,耕地及建设用地逐渐成为影响水质的主要土地利用/覆盖类型。
(4)河流底栖硅藻分布受水质影响较大,而受季节变化的影响较小。①冗余分析(RDA)表明,电导率、NH4+、HCO3-、NO3-及   Na+等5个水质因子及Chl a、平均底质组成(MSUBST)对硅藻空间分布有显著影响(p<0.05)。②  RDA双序图结果表明,对照溪流、城市上游河道及城市下游河道的硅藻组成受环境影响差异明显。在对照溪流,自然底质组成、河岸较高的植被覆盖度和低浓度污染物等环境因子与A.minutissima等种类相关性较好;城市上游河道,较高比例的不透水表面和相对较低的污染物浓度等环境因子与          P.brevistriata和 S.construens var. venter等相关性较好;在城市下游河道,较高比例的不透水表面,高浓度污染物等环境因子与 N.  palea等相关性较好。③典范对应分析(CCA)表明,Cl-、SiO2、NO3-、TN、WT、Cond.、Mg2+、SO42-、Ca2+、NH4+、K+及
Na+等水质指标对硅藻季节变化有显著影响(p<0.05)。④  CCA双序图结果表明,对照溪流、城市上游河道及城市下游河道的硅藻组成与环境因子之间的关系季节变化相对较小。本文有助于深入认识和理解在城市化背景下河流生态系统的变化特征和过程,并可为城市河流水环境质量的管理和调控提供重要的科学理论依据。
英文摘要:      Urbanization dramatically  affects hydrology systems,  water quality, and  aquatic ecosystem  composition in  urban  streams. In  this  study, we  characterized  the water quality and diatom  assemblage composition  along a rural  to urban gradient  to assess impacts of  urbanization on  stream  ecosystems in  Beijing, China.  The effects  of the spatiotemporal  dynamics  of  urbanization on  water  quality  and  diatom  assemblage composition were  investigated using remote  sensing data, field  survey and statistical analysis. The  analysis was  conducted at  two  spatial scales.  On the  watershed scale,land use  and land  cover  (LULC) data  in four  watersheds belonging  to three  spatial scales  (rural, urban,  and  exurban) was  obtained  from TM  data  in 2000,  2005,  and 2010.  Water  quality data  were  collected  from  2000  to  2010. Relationships  of  the LULC types in  the buffers of 100  m to 2000 m  and water quality were  calculated by Pearson analysis,  Redundancy analysis  (RDA), and multiple  regression analysis.  On the sampling scale,  LULC data of  the fifth-ring roads  in the city were  obtained from ALOS imagery  in 2010.  Water quality and  diatom assemblages  were collected from urban upstreams,  urban downstreams, and  reference streams from May  to November in 2014. The spatial and temporal patterns of the water quality and diatom  assemblage were  quantified,  and   the  relationships  among  LULC,   water  quality,  and   diatom assemblages  were analyzed  using  multiple regression  analyses.  The major  findings and conclusions were summarized as follows:
    1. Water  quality was  significantly different  (p<0.05) at  both the  watershed and sampling site level among the urban,  suburban, and rural sites, but with no significant seasonal difference  (p>0.05) at  both scales. (1)  The water quality  in rural  watershed was better than urban  watershed and exurban watershed, the water  quality of exurban watershed  was  the worst  in  the  three  watersheds.  The  concentration of  BOD,  for example,  was  115.8  mg/L in  exurban  watershed,  higher  than  37.1  mg/L in  urban watershed and 2.22  mg/L in rural watershed (p<0.001).  (2) Water quality was  getting better in Beijing: the concentration of  pollutants was decreasing from 2000 to 2010 in urban and exurban  watershed. The concentration of  COD Mn  was 10.7 mg/L in 2000,decreased to 8.33 mg/L in 2005 and 5.25 mg/L in 2010 (p<0.05). The concentration of pollutants in rural watershed, however, increased from 2000 to 2010 (p>0.05). (3) The water  quality in  urban  downstream  was higher  than  urban upstream  and  reference stream (p<0.05). For example,  the average concentration of Cond. was  946.8 mg/L in urban downstream,  higher  than 463.3  mg/L in  reference  stream and  388.6 mg/L  in urban upstream (p<0.05). But  most of the water quality indicators  have no significant difference  between  urban   upstream  and  reference  stream   (p>0.05).  (4)  Seasonal variations  of   the  water  quality   indicators  have   no  significant  difference   in  the sampling sites.  But the seasonal  variation of the  water quality indicators  was greater in reference stream than in urban upstreams and urban downstreams.
    2. The diatom  assessblages composition was  very different among  the sampling sites  at different  spatial locations  (i.e.,  urban, suburban,  and rural),  but  the relative abundance and the diversity index had no significant difference across season.  (1) The diatom assessblages  composition was divided  into reference stream,  urban upstream, and  urban  downstream   by  cluster  analysis.   Achnanthidium  minutissima  was   the dominant   species   in   reference   stream,   and   Pseudostaurosira   brevistriata   and Staurosira construens  var. venter  were the dominant  species in  urban upstream, and Nitzschia palea  was the  dominant speices  in reference  stream. The  characteristic of the dominant  species  relative abundance  changes  was greater  in urban  downstream than in  reference stream  and urban  upstream. (2)  Relative abundance  of the  species had  no   significant  difference  among   spring,  summer   and  autumn.  The   relative abundance‟s  seasonal  variation  of  A.  minutissima and  P.  brevistriata  was  spring> autumn> summer, the seasonal variation of S. construens var. venter and N.  palea  was spring>  summer>  autumn. (3)  The  characteristic  of  the diversity  index  of  species richness  (S),  Shannon  diversity  (H‟),  Simpson  (D‟)  and  Pielou  (J‟)  changes  was greater  in  reference   stream  than  in   urban  upstream  and  urban   downstream.  (4) Seasonal variation  of the  diversity index  was different among  the sampling  sites. In reference stream, the seasonal variation of S, H‟, and J‟ was autumn> summer> spring,and the seasonal variation of D‟ was autumn> spring> summer. In urban upstream, the seasonal variation  of  S was  autumn> summer>  spring, the  seasonal  variation of  H‟ and  D‟ was  summer>  autumn>  spring,  but the  index  of  J‟  was summer>  spring> autumn. In  urban  downstream, the  seasonal variation  of the  all index  was autumn> spring> summer.
    3. There was  a strong correlationship between  LULC and water quality.  (1) The proportion of the  LULC types was significant  difference in the watersheds.  From the buffer of  100 m to 2000  m, forest land  was the main  LULC type in  rural watershed,impervious surface (Imp) was the main  LULC type in urban watershed, and crop land was the  main LULC type  in exurban watershed. (2)  LULC types  have very different impact  on  water quality.  Forest  land  was  positively  correlated with  water  quality. Pearson analysis results showed that the forest land was positively correlated with  DO, but negatively correlated with NH3-N, BOD, COD  Cr and COD Mn from 100 m to 2000m. However, the LULC types of  water, crop, and Imp were negatively correlated with water quality. They were negatively correlated with DO, but positively correlated with NH3-N, BOD,  COD  Cr and  COD  Mn except  for Imp, which  was negative  correlation with COD  Cr from 100 m to 2000 m. (3)  Multiple regression analysis results indicated that  buffer sizes  were  very important  for  studying the  relationship  between  LULC types and water quality.  In buffers of 100 m  and 200 m, forest  land was an important factor for water  quality. But in  the 300 m to  600 m buffers,  the mixed types of  crop, impervious surface,  water, and forest  were significantly affected  water quality. From 800 m  to 2000 m,  however, crop land  and impervious surface  were the main  factors affecting water quality.
    4. Water quality  had great impact on  the distribution of the diatom  assamblages,but the seasonal variations  of water quality have  no significant impact on the  relative abundance of  diatom species. (1)  Monte carlo  permutation test of  RDA showed that Cond, NH4+, HCO3-, NO3-, and Na+ and  Chl a, MSUBST have a significant impact on the spatial patterns  of the diatom  assamblages (p<0.05). (2) RDA ordination  diagram showed   the   distribution   of   the   diatom   assamblages    greatly   affected   by   the environmental  indicators. In  reference stream,  the  diatom assamblages  composition correlated with high  proportion of green cover  near the stream, natural  substrate, and low concentration  of  pollutants. But  in  urban downstream,  the diatom  assamblages composition correlated  with high  proportion of  Imp cover  near the  stream, artificial substrate,  and   high  concentration   of  pollutants.   In  urban   upstream,  the  diatom assamblages  composition  correlated  with  high   proportion  of  Imp  cover  near  the stream,  artificial  substrate,  and  low   concentration  of  pollutants.  (3)  Monte  carlo permutation test of Cannonical correspondence analysis (CCA) showed  that Cl-, SiO2,NO3-, TN, WT, Cond., Mg2+, SO42-, Ca2+, NH4+, K+, and Na+ have a significant impact on  the seasonal  variation  of the  diatom  assamblages (p<0.05).  (4)  CCA ordination diagram  showed  the  seasonal  variations  of  the  diatom  relative  abundance  in  the sampling sites have no strong correlation with the environmental change.
     The results  were  important for  understanding the  characteristic  and process  of urban  stream  ecosystem  changes affected  by  urbanization.  In  addition,  the  results provide important insights on water  quality regulation and control in urban streams in Beijing.

 
 
内容类型: 学位论文
URI标识: http://ir.rcees.ac.cn/handle/311016/36780
Appears in Collections:城市与区域生态国家重点实验室_学位论文

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陈向. 城市化对河流生态系统的影响研究--以北京市为例[D]. 北京. 中国科学院研究生院. 2016.
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