Responses of Freshwater Diatoms and Macrophytes Rely on the Stressor Gradient Length across the River Systems

Phytobenthic diatoms and macrophyte communities respond differently to stressors in aquatic environments. For the assessment of ecological status rivers Slovenia, we use several indices, including River Macrophyte Index (RMI) Trophic index (TI) based on phytobenthic communities, respectively. In present study, examined relationships between nutrient variables values RMI TI using varied stressor gradient lengths. We also aimed explain variability diatom with different stressors, namely nutrients land cover their combinations. The significantly were affected by length gradient. obtained a stronger relationship total phosphorous at an approximately <0.3-mg/L annual mean value, while, for TI, significant bigger greatest share community was explained combination lowest phosphorus nitrogen variables. When applied composite gradient, it similar both (up 26%). A principal component analysis (PCA) revealed that EQR PCA1 represents intensive agriculture depends shorter gradients lower decreased as extended towards higher values. Both tested methods showed are more sensitive values, whereas longer stressor.