Unlocking the relationship of biotic integrity of impaired waters to anthropogenic stresses

A concept of a layered hierarchical model that will link the watershed, landscape and stream morphology pollution stressors to the biotic assessment endpoints (IBIs) is described. The key groups of structural components of the model are: IBIs and their metrics in the top layer, chemical water and sediment risks and a habitat quality index in the layer below, in-stream concentrations in water and sediments and channel/habitat impairment parameters in the third layer, and watershed/landscaper pollution generating stressors, land use change rates, and hydrology in the lowest layer of stressors. A modified and expanded Maximum Species Richness concept is developed and used to reveal quantitatively the functional relationships between the top two layers of the structural components and parameters of the model.