Assessment of the status of habitat in the Nation's aquatic ecosystems

Habitat degradation from human activities has severely impacted the Nation’s aquatic ecosystems.  To protect and restore these systems, a status assessment of habitat conditions at a national scale is critical.  Currently, the U.S. lacks such a comprehensive and objective tool, undermining protection opportunities and compromising development of restoration strategies.  We attempt to address that need, drawing from a landscape approach to develop an assessment framework, build databases, and perform a national assessment.  Our hierarchical assessment framework allows for evaluation at multiple spatial scales from river reaches to the entire nation.  It also facilitates data exchange, ensuring that assessment results can inform other efforts and that new information can refine the assessment.  Our initial assessment has been performed on rivers of the conterminous U.S. for 2.6 million stream reaches in the NHD+.  We derived assessment scores from human disturbances, including land uses, river connectivity, point sources, and imperviousness.  Scores are based on disturbance summaries in local and network catchments reflecting the influence of multi-scale controls and are weighted by expert-based ranking of relative impacts on facets of ecological integrity like flow and temperature regimes and water chemistry.  Future work will include assessment of Alaska and Hawaii and a nation-wide lakes assessment.