Aplicação da análise das componentes principais na ordenação dos parâmetros físico-químicos no alto rio Madeira e afluentes, Amazônia Ocidental..

Abstract

We used principal components analysis (PCA) to evaluate the physicochemicalparameters of the Upper Madeira River and its tributaries in the state of Rondônia,Brazil. The physicochemical parameters indicated that the Madeira River drainagebasin comprises three groups of waters regarding pH (slightly alkaline to slightly acid),conductivity (high to low), and dissolved oxygen and suspended solids. The PCA of thephysicochemical parameters demonstrated the influence of pH, conductivity anddissolved solids in the total variability: the PCA scores revealed differences resultingfrom the seasonal influences of high and low waters (rain and dry seasons). The flowand physicochemical parameters could be discriminated according to seasons, whichare affected by marginal soils, land use (agriculture and cattle ranging), floodedwetlands, and by the specific tributaries’ physicochemical-characteristics