Since its establishment in 1903, the National Wildlife Refuge System (NWRS) has grown to 635 units and 37 Wetland Management Districts in the United States and its territories. These units provide the seasonal habitats necessary for migratory waterfowl and other species to complete their annual...

Biological integrity, environmental health, and naturalness are increasingly relevant to the management of conservation lands. Biological integrity and environmental health, integrated via the concept of ecological integrity, imply the recognition of natural conditions. A holistic and adaptable...