To date, the majority of the reserves have engaged in restoration science and have planned or conducted small to medium-scale restoration projects (.5 to 250 acres). An inventory of key habitats at the reserves and restoration activities and priorities conducted in 2000 and updated in 2001 is summarized in the NERRS Restoration Science Strategy. Reserves have investigated both engineering and natural approaches to restore areas to approximate natural, unaltered conditions. Several reserves must first address water quality issues and/or restore hydrologic regimes (i.e. sheet flow, tidal exchange, and freshwater drainage) before they can restore terrestrial and aquatic native plant communities and achieve faunal and ecological recovery.