黄河三角洲石油生产对东营湿地底栖动物群落结构和水质生物评价的影响

Abstract

为了解石油开采对湿地生态系统的影响,2009年10月调查了黄河三角洲东营湿地34个样点的水体物理化学属性和大型底栖无脊椎动物群落结构。共获得3门6纲12目41科70属84个大型底栖无脊椎动物分类单元。Shannon-Wiener多样性指数(<em>r</em>=-0.446,<em>P</em>=0.02)和TN显著负相关,<em>BI</em>指数与理化指标无显著相关性;软体动物分类单元数与盐度(<em>r</em>=-0.422,<em> P</em>=0.028)显著负相关,与pH值(<em>r</em>=0.435,<em>P</em>=0.023)显著正相关;软体动物个体百分数同样与盐度(<em>r</em>=-0.395, <em>P</em>=0.041)呈显著负相关,与pH值(<em>r</em>=0.565, <em>P</em>=0.002)呈极显著正相关;寡毛类分类单元数与TN(<em>r</em>=0.524,<em> P</em>=0.005)极显著正相关。水体石油含量与生物指数无显著相关性。典范对应分析(CCA)显示,TN、pH、盐度是影响东营湿地底栖动物群落结构的主要环境变量,水体石油污染并不是主要的胁迫因子。寡毛类和软体动物是该地区对环境变化的主要指示生物类群。Shannon-Wiener多样性指数水质生物评价结果显示,溢洪河支流、广利河上游、挑河上游、东张水库属于清洁;轻污点位有9个,其余点位为中污或重污。;The major environmental risks associated with petroleum extraction (e.g. oil spills and leaks) are well known. There is a lot of information on the impacts of petroleum exploration on benthic communities in foreign studies. In this study, we probed the effects of petroleum exploration on macro-invertebrate assemblages, which are important components of benthic communities in this wetland ecosystem. The object of the investigation was to provide scientific data to guide the management, ecological restoration, conservation of biodiversity, and sustainable development of aquatic ecosystems. Physicochemical variables were measured at 34 sites in the Yellow River Delta wetland, Dongying, China, in October 2009, and benthic macro-invertebrate assemblages were collected using a D-frame net and a Peterson grab. The water body in the study area was oligohaline, its salinity ranging between 0.05 and 5 ppt. A total of 84 macro-invertebrate taxa, belonging to 70 genera, 41 families, 12 orders, 6 classes, and 3 phyla, were collected. Insecta comprised 52.4% of all benthic invertebrate taxa, of which Odonata and Diptera accounted for 23% and 24%, respectively. The structure and diversity of macro-invertebrate assemblages were expressed using the Shannon-Wiener index, the Margalef index and the dominance index. Water quality was assessed by the Shannon-Wiener index and the biotic index. The dominant species at most of the sites were either <em>Chironomus</em> spp. or <em>Glyptotendipes</em> spp. with overall dominance indices of 0.0315 and 0.0522, respectively. Pearson correlation analysis showed that the Shannon-Wiener index was negatively correlated with total nitrogen (TN) (<em>r</em>=-0.446, <em>P</em>=0.02) but was not correlated with any of the other physicochemical variables measured. The biotic index was not correlated with any of the physicochemical variables. The numbers of molluscan taxa were negatively correlated with salinity (<em>r</em>=-0.422, <em>P</em>=0.028) and positively correlated with pH (<em>r</em>=0.435, <em>P</em>=0.023). Likewise, the percentages of individual Mollusca at the sites were negatively correlated with salinity (<em>r</em>=-0.395, <em>P</em>=0.041) and positively correlated with pH (<em>r</em>=0.565, <em>P</em>=0.002). The numbers of oligochaete taxa were significantly positively correlated with TN (<em>r</em>=0.524, <em>P</em>=0.005). The petroleum content of the water was not correlated with any of the biological indices and was not considered to be a major stressor. Canonical correspondence ordination analysis (CCA) showed that TN, pH, and salinity were the major contributors to the macro-invertebrate community structure, with 12.18% of species variation explained by these three variables. The substrate and hydrophytes also had effects on the structure of the macro-invertebrate communities. Cluster analysis and MDS ordination of sampling sites showed that all sites could be divided into 11 separate groups at the similarity level of 30%. Oligochaeta and Mollusca were the two main taxa responsive to environmental variables. The bio-assessment indicated that the Shannon-Wiener diversity index was a better indicator of water quality than the biotic index. Bio-assessment using the Shannon-Wiener index showed that the water quality of the Yihong River tributary, the Guangli River upstream, the Tiao River upstream, and the Dongzhang reservoir were clean, that nine sites were slightly polluted, and that the remaining sites were moderately to heavily polluted. We proposed that a comprehensive evaluation of water quality should ideally combine the Shannon-Wiener index, the biotic index, and physicochemical measurements. Additionally, other evaluation methods could be developed based on the biological indices for this region, taking into account the special characteristics of this native ecological environment.