San Diego National Wildlife Refuge
The Otay-Sweetwater Unit of the San Diego National Wildlife Refuge is part of the National Wildlife Refuge System's contribution to the Multiple Species Conservation Plan, a program designed to conserve enough open space and habitat for species survival while enabling orderly development to occur where necessary.
San Diego National Wildlife Refuge's abundance of coastal sage and chaparral are an important addition to other inland preserves established to conserve and restore fast diminishing habitat. This inland refuge is home to such endangered birds as Least Bell's Vireo, California Gnatcatcher, a rare butterfly, the Quino Checkerspot and to the San Diego Horned Lizard. Biological surveys for other species are ongoing as new land is acquired. The approved refuge boundary for the San Diego Refuge is 44,000 acres (180 km2), and 8,000 acres (32 km2) for the Vernal Pools Unit.