San Diego National Wildlife Refuge is a National Wildlife Refuge

National Wildlife Refuge

National Wildlife Refuge is a designation for certain protected areas of the United States managed by the United States Fish and Wildlife Service. The National Wildlife Refuge System is the world's premiere system of public lands and waters set aside to conserve America's fish, wildlife and plants...

 in California

California

California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

. It is part of the San Diego National Wildlife Refuge Complex

San Diego National Wildlife Refuge Complex

The San Diego National Wildlife Refuge Complex is a series of wildlife refuges established by the United States National Wildlife Service beginning in 1972. The complex incorporates six locations in San Diego County and Orange County in California.-History:...

.

A variety of habitats from coastal sage

Salvia

Salvia is the largest genus of plants in the mint family, Lamiaceae, with approximately 700-900 species of shrubs, herbaceous perennials, and annuals. It is one of several genera commonly referred to as sage. When used without modifiers, sage generally refers to Salvia officinalis ; however, it is...

 scrub and chaparral

Chaparral

Chaparral is a shrubland or heathland plant community found primarily in the U.S. state of California and in the northern portion of the Baja California peninsula, Mexico...

 to oak

Oak

An oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...

 woodland

Woodland

Ecologically, a woodland is a low-density forest forming open habitats with plenty of sunlight and limited shade. Woodlands may support an understory of shrubs and herbaceous plants including grasses. Woodland may form a transition to shrubland under drier conditions or during early stages of...

 and freshwater

Freshwater

Fresh water is naturally occurring water on the Earth's surface in ice sheets, ice caps, glaciers, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams. Fresh water is generally characterized by having low concentrations of dissolved salts and...

 marsh

Marsh

In geography, a marsh, or morass, is a type of wetland that is subject to frequent or continuous flood. Typically the water is shallow and features grasses, rushes, reeds, typhas, sedges, other herbaceous plants, and moss....

 describe this inland refuge in San Diego's backcountry.

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

California Gnatcatcher

The California Gnatcatcher, Polioptila californica, is a small 10.8 cm long insectivorous bird which frequents dense coastal sage scrub growth...

, a rare butterfly, the Quino Checkerspot

Quino Checkerspot

The Quino Checkerspot is native to California and Mexico. It is a subspecies of the common Edith's Checkerspot and the second such subspecies to be listed under the federal Endangered Species Act. This species, like many others, has undergone several changes in nomenclature and classification...

 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 44000 acres (178.1 km²), and 8000 acres (32.4 km²) for the Vernal Pools Unit.