太子河河岸带土地利用类型与硅藻群落结构的关系

为了评价河岸带土地利用对河流硅藻群落的影响,于2012年5月对太子河河岸带4种主要土地利用类型(森林用地、森林耕作用地、耕地、城镇建设用地)下38个采样点的硅藻群落和水环境特征进行采样分析. 结果表明:森林用地的指示种为膨大桥弯藻(Cymbella turgida)、优美桥弯藻(C. delicatula)、弧形峨眉藻(Ceratoneis arcus)、Gomphonema trancatum等寡污指示种；耕地的指示种为颗粒直链藻(M. granulate)、库津小环藻(Cyclotella kuetzingiana)、线形菱形藻(N. linearis)、尖布纹藻(Gyrosigma acuminatum)等污染指示种. 聚类分析结果显示,相同土地利用类型区域内,硅藻群落结构特征较为相似. 典范对应分析显示,ρ(COD_Mn)、ρ(SS)(SS为悬浮物)和ρ(TDS)(TDS为总溶解固体)是影响硅藻群落结构特征的主要水环境因子. 不同土地利用类型区域内硅藻群落结构特征差异显著,其中,森林用地内硅藻生物指数(17.98)和硅藻属数量(17.33个)最高,Shannon-Wiener多样性指数(2.22)和Pielou均匀度指数(0.54)最低；耕地内Shannon-Wiener多样性指数和Pielou均匀度指数平均值最高,分别为3.37和0.82；城镇建设用地内物种丰富度(11.00)、硅藻生物指数(9.20)和硅藻平均密度(0.71×104 L-1)最低. 研究显示,不同土地利用类型通过对水环境因子的影响进而影响硅藻群落的变化,其中城镇建设用地面积所占比例较高的河流水环境质量和硅藻群落状况最差；太子河河岸带土地利用类型对河流硅藻群落结构影响显著,并表现出明显的空间异质性. 

Relationship between Land Use Types within Riparian Zones and Community Structure of Diatom in Taizi River, China

To evaluate the effects of land use types (e.g. forest land, farmland, combination of forest land and farmland and urban land) within riparian zones on diatom community structure, the community structure of diatom and physical and chemical characteristics of water bodies were investigated at 38 sampling sites in the Taizi River, China. Cluster analysis of diatom communities showed that the same type of land use area exhibited relatively similar characteristics of diatom community structure. Indicator species analysis showed that the indicator species of forest were Cymbella turgida, Cymbella delicatula, Ceratoneis arcus and Gomphonema trancatum; the indicator species of farmland were M. granulate, N. linearis, Gyrosigma acuminatum and Cyclotella kuetzingiana. Canonical correspondence analysis showed that the COD_Mn, suspended solids and the total dissolved solid were the main factors influencing the diatom community structure characteristics in the Taizi River. The characteristics of diatom community showed an apparent divergence in the four land use types:the mean values of IDG and IBD were the highest in the forest, being 17.33 and 17.98 respectively. The mean values of Shannon-Wiener diversity and Pielou evenness index were the highest in farmland, being 3.37 and 0.82 respectively, and the lowest in forest, being 2.22 and 0.54 respectively. The mean values of species abundance, IBD and density were the lowest in urban land, being 11.00,9.20 and 0.71. The results indicated that land use types affect the diatom community structure by influencing environment conditions, and water quality and diatom community conditions were poor in urban land. Land use types within riparian zones significantly influence the diatom community structure in the Taizi River, which showed an obvious spatial heterogeneity. The study showed that the land use types within riparian zones might affect water environment quality and diatom community structure of the river.