Quantitative relationships of invertebrates to pH in Norwegian river systems
Quantitative relationships of invertebrates to pH in Norwegian river systems
复制标题
挪威河流系统中无脊椎动物与 pH 值的定量关系
作者：
J. Larsen;H. J. B. Birksl;G. Raddum;A. Fjellheim
对挪威21条无边界的酸性河流系统的无脊椎动物群进行了调查。数据包括180个样品和127个无脊椎动物分类群以及相关的水化学数据（pH、钙、酸中和能力、总铝和电导率）。采用多元数值方法量化了水生无脊椎动物与水化学之间的关系。非趋势正则对应分析（DCCA）显示了pH和铝的高相关性变化的一个主导轴。DCCA轴2与钙含量显著相关。采用加权平均（WA）回归校正和加权平均偏最小二乘回归（WA- pls）方法探讨了无脊椎动物对pH的预测能力。根据（观测pH值-推断pH值）的均方根预测误差（RMSEP）报告了这些方法的性能。Bootstrapping和leave- out jackknife被用作交叉验证过程。无脊椎动物的预测能力较好（对WA的RMSEPboot = 0.309 pH单位）。无脊椎动物与硅藻研究的比较表明，无脊椎动物与硅藻一样是现代pH值的良好预测者。RMSEPjack表明，WA-PLS提高了预测能力。通过高斯回归找到pH的指示分类群。异翅目、灰鳞目、边缘瘦翅目、黄翅目和夜翅目呈显著的s型曲线，丰度随ph的降低而增加。黄翅目呈显著的单峰响应，在梯度的酸性部分估计最优。随着pH值的增加，异形虫和介形虫的丰度呈显著的s型响应，而北方双翅虫、南翅虫、grammatica异形虫、暗箱虫和burmeisteri Siphonoperla的丰度呈显著的单峰响应，且pH值较高。许多类群的单峰或s型曲线在统计上不显著，但WA发现它们具有高pH或低pH的特征。这些结果表明，需要结合使用高斯回归和直接梯度分析来全面了解潜在指标类群。
The invertebrate fauna has been surveyed for twenty one unlimed generally acidic river systems in Norway. The data consist of 180 samples and 127 invertebrate taxa and associated water chemistry data (pH, calcium, acid neutralizing capacity, total aluminium, and conductivity). Multivariate numerical methods are used to quantify the relationships between aquatic invertebrates and water chemistry. Detrended canonical correspondence analysis (DCCA) shows one dominant axis of variation with high correlations for pH and aluminium. DCCA axis 2 is significantly correlated with calcium. The predictive abilities of invertebrates to pH are explored by means of weighted averaging (WA) regression and calibration and weighted averaging partial-least-squares regression (WA-PLS). The performance of the methods is reported in terms of the root mean square error of prediction (RMSEP) of (observed pH-inferred pH). Bootstrapping and leave-one-out jackknifing are used as cross-validation procedures. The predictive abilities of invertebrates are good (RMSEPboot for WA = 0.309 pH units). Comparison of the invertebrates with diatom studies shows that invertebrates are as good predictors of modern pH as diatoms are. RMSEPjack shows that WA-PLS improves the predictive abilities. Indicator taxa for pH are found by Gaussian regression. Anisoptera, Agrypnia obsoleta, Leptophlebia marginata, Sialis lutaria, and Zygoptera have significant sigmoidal curves where abundances increase with decreasing pH. Cyrnus flavidus shows a significant unimodal response and has an estimated optimum in the acid part of the gradient. Isoperla spp. and Ostracoda show significant sigmoidal responses where abundances increase with increasing pH. Amphinemura borealis, Diura nanseni, Isoperla grammatica, I. obscura, and Siphonoperla burmeisteri show significant unimodal responses and have high pH optima. Many taxa do not have statistically significant unimodal or sigmoidal curves, but are found by WA to be characteristic of either high pH or low pH. These results suggest that a combined use of Gaussian regression and direct gradient analysis is needed to get a full overview of potential indicator taxa.