太子河流域硅藻群落与驱动因子的定量关系

定量研究水生生物对水环境参数的适宜值是评估栖息地质量和维持生物完整性的主要途径. 以辽宁省太子河流域为研究范例,选择Y(优势度指数)大于0.000 1的硅藻为研究对象,结合水环境参数,采用CCA(典范对应分析)、CART(分类回归树)和WA(加权平均回归分析)等方法,分析硅藻与水环境因子的关系,并计算硅藻对驱动因子的最适值. CCA结果表明,IOS(底质指数)、ρ(TDS)(TDS为总溶解固体)和ρ(COD_Mn)是硅藻群落的驱动因子；CART预测结果表明,IOS高的水环境硅藻密度高于IOS低的水环境,ρ(TDS)和ρ(COD_Mn)低的水环境硅藻密度高于ρ(TDS)和ρ(COD_Mn)高的水环境；WA结果显示,96种硅藻对IOS、ρ(TDS)和ρ(COD_Mn)的最适值范围分别为1.00~6.44、60.29~820.30 mg/L和0.46~2.89 mg/L. 钝端菱形藻解剖刀变种和尖端菱形藻适宜栖息于IOS较低而ρ(COD_Mn)较高的水环境, Gomphonema trancatum和肿大桥弯藻则适宜栖息于IOS较高的水环境；缠结异极藻二叉变种和尖细异极藻适宜栖息于ρ(TDS)较高的水环境,弧形峨眉藻和克洛钝脆杆藻则适宜栖息于ρ(TDS)较低的水环境；弧形峨眉藻和隐头舟形藻威蓝变种适宜栖息于ρ(COD_Mn)较低的水环境. 针杆藻和桥弯藻对IOS的最适值高于舟形藻和菱形藻以及其他藻种,96种硅藻对ρ(TDS)和ρ(COD_Mn)的最适值均表现为菱形藻和异极藻较高、针杆藻和桥弯藻较低. 

Quantitative Relationships among the Diatom Community and Driving Factors in Taizi River Basin, China

The relationship between aquatic organisms and environmental factors as determined by quantitative analysis is a common approach to assess habitat quality and maintain biological integrity. Diatoms are important tools in assessment of human impacts on stream water quality and ecological integrity. It is important to establish diatoms habitat suitability with environmental variables in water ecosystem health evaluation. The aim of this study was to clarify the quantitative relationship between diatom species assemblages and water environments of Taizi River Basin based on canonical correspondence analysis (CCA), classification and regression tree (CART) and weighted average (WA). CCA showed that index of substrate (IOS), total dissolved solids (TDS) and permanganate index (COD_Mn) were highly correlated with the diatom assemblages. CART revealed that diatoms density from higher IOS was higher than that of lower IOS, and the diatom density from lower concentration of TDS and COD_Mn was higher than that of higher concentration of TDS and COD_Mn. The WA indicated that the appropriate values for the 96 species of diatoms adapting to IOS, TDS and COD_Mn were from 1.00-6.44,0.29-820.30 mg/L and 0.46-2.89 mg/L, respectively. Nitzschia obtusa var. Scalpelliformis, Nitzschia acula were mainly suitable for the lower IOS and higher concentration of COD_Mn; on the contrary, Gomphonema trancatum and Cymbella tumidula were mainly suitable for the high IOS. Gomphonema intricatum var. dichotomiformis and Gomphonema acuminatum were living with higher concentrations of TDS, while Ceratoneis arcus and Fragilaria crotonensis were living with lower concentrations of TDS. Ceratoneis arcus and Navicula cryptocephala var. venta mainly perched on the lower concentration of COD_Mn. The values of IOS for Synedra and Cymbella were higher than Navicula, Nitzschia and other diatom species. Furthermore, for Nitzschia and Gomphonema, the concentrations of TDS and COD_Mn were higher than any others, which were lower for Synedra and Cymbella.