Guam National Wildlife Refuge was established in 1993, to protect and recover endangered and threatened species, protect habitat, control non-native species with emphasis on the brown tree snake, protect cultural resources, and provide recreational and educational opportunities to the public where possible. The refuge receives over 90,000 visits a year from island residents and tourists. Current plans are to renovate the facilities to improve research capabilities, improve administrative and maintenance capabilities of the refuge staff, and establish a visitor and interpretive center. The refuge is composed of 771 acres (371 acres of coral reefs and 400 acres of terrestrial habitat) owned by the U.S. Fish and Wildlife Service, and 22,456 acres (mostly forest) owned by the Department of Defense in Air Force and Navy installations that are classified as refuge overlay. The Ritidian Unit of Guam Refuge (owned by the Fish and Wildlife Service) was created from a small decommissioned, specialized naval installation. The transfer included buildings as well as habitat.