Aquatic Index of Ecological Integrity

This dataset represents Aquatic index of ecological integrity (IEI), which is a measure of relative intactness (i.e., freedom from human modifications and disturbance) and resiliency to environmental change (e.g., as caused by disturbance and climate change). Raw IEI is a composite index derived from 19 different landscape metrics that measure different aspects of intactness and resiliency. For the derivation of this layer, raw IEI is (quantile) scaled by ecological system and HUC6 watershed so that the poorest cell of each ecological system gets a 0 and the best gets a 1 within each watershed. Aquatic IEI, is provided for convenience in displaying the results of the aquatic conservation design but is otherwise equivalent to Weighted IEI except that it only has values for aquatic cells (all non-aquatic cells are set to nodata), is technically unweighted IEI. IEI is a major component of the terrestrial and aquatic core area selection indices and thus the terrestrial and aquatic network of core areas.