Resource Management


 The San Luis NWR Complex must actively manage each refuge unit to enhance habitat conditions and promote wildlife. Past changes to the northern San Joaquin Valley – loss of habitats and species, alterations to natural hydrology, and the introduction and establishment of exotic plants and animals – necessitates proactive natural resources management activities.

The Complex conducts wildlife and habitat monitoring programs to ascertain plant and animal distributions and abundances, and to gauge the success of management programs. Waterbird and songbird surveys are routinely conducted on refuge units. Less well-known techniques that are employed to study certain wildlife species include remote camera stations, spotlight surveys, bird banding stations, search dog scenting surveys, and others.

For wildlife which has been locally extirpated, the Complex works with partners to reintroduce certain species to its refuge units. Black-tailed deer have been reintroduced in recent years to the San Luis National Wildlife Refuge and can be viewed along riparian corridors. The endangered riparian brush rabbit has been re-established on the San Joaquin River National Wildlife Refuge using rabbits produced from a captive breeding facility. The program has been successful with native-born rabbits now found on the Refuge.

Artificial dens and other habitat structures are constructed on the Complex to benefit wildlife with very specific needs. These include nest boxes for songbirds, owls, and wood ducks, buried culverts to create dens for kit foxes, raised mounds to create high ground refugia during floods for small mammals, and islands in wetlands for nesting/roosting waterfowl. Habitat management and restoration are frequent activities at the Complex and require significant efforts to conduct.

Wetland habitat management requires an infrastructure of water conveyance canals, water control structures, pumps, and wells to manage the 150+ individual wetland units or ponds at the Complex. These wetland units support a tremendous variety and abundance of waterbirds. Most of the Complex’s wetlands are managed as moist soil units where important wetland food plants, in particular smartweed, watergrass, sedge, and swamp timothy are grown as forage for waterbirds. Seasonal wetlands are drained in spring, irrigated once or twice during the early summer, and flooded in late summer and early autumn. The careful timing of flooding and draining wetlands encourages the key wetland plants to grow, and coincides with bird migration so that most wetland units are flooded when waterbirds are using the Central Valley. In addition to these seasonal wetlands, the Complex also maintains a smaller amount of year-round permanent wetlands and summer wetlands for breeding waterbirds.

Riparian woodlands are key wildlife travel corridors for many Central Valley wildlife species and provide unique breeding sites for many migratory birds. The Complex restores fallow agricultural lands to riparian woodlands or native grasslands and wetlands. Restoring riparian woodlands requires planting stocks of a variety of woody species including willow, ash, and cottonwoods, as well as irrigating the first few years after planting.

Woodland habitat maintenance requires periodic disturbance of senescent, or aging, stands and providing conditions suitable for regeneration.

Grasslands are the most common habitat at the Complex. These habitats support geese, cranes, songbirds, elk, raptors, and a host of other wildlife. These grasslands are managed by a variety of techniques including prescribed burning, grazing, mowing, and disking. The Complex also restores native grasslands by preparing the ground and seeding with native grass species and/or planting grass plugs.