Field Notes
U.S. Fish & Wildlife Service
Field Notes Entry   
ENDANGERED SPECIES: Many Happy Returns: CNO Refuges Help Restore and Recover Rare Species in California
California-Nevada Offices , July 12, 2007
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By Diane Elam with contributions from California National Wildlife Refuge staff

National Wildlife Refuges in California are playing a pivotal role in moving listed species towards recovery.  Their contributions focus on habitat restoration which has prompted the return of a bird lost to the Central Valley and the potential delisting of an insect, as well as protecting and managing habitat for many other listed species and supporting listed species propagation.  While many people are aware of Hopper Mountain NWR Complex’s role in the recovery of the California Condor, some examples of lesser known recovery activities on Refuges are detailed below.


A Long Absence – Least Bell’s Vireo.  In 2005, a riparian woodland restoration site on the San Joaquin River National Wildlife Refuge attracted some surprise visitors – a nesting pair of endangered least bell’s vireos (Vireo bellii pusillus).  The least bell's vireo once was common from Red Bluff down throughout the Central Valley and into Baja California.  But the loss of much of the Valley’s riparian habitat resulted in their steep decline and loss from the Valley.  The last confirmed Valley breeding record was in 1919, and by the 1940s, the bird was no longer detected in the Valley.  The 2005 nesting was an historic event.  It marked the return of a bird long absent from the Valley and symbolized the importance of riparian woodland restoration efforts on the Refuge.  The vireos returned to nest again in 2006 and 2007.  Known to exhibit high faithfulness for breeding sites (philopatry), the birds have nested in arroyo willows in proximity to the previous years’ nest sites.  Refuge biologists carefully monitor the nests and hope that young birds hatched on the Refuge will return to breed.


A Species Recovered – Valley Elderberry Longhorn Beetle.  The valley elderberry longhorn beetle (Desmocerus californicus dimorphus,VELB) was once thought to be restricted to a mere three drainages.  After the species was listed, a substantial amount of riparian habitat for VELB was preserved and restored, especially at the Sacramento National Wildlife Refuge Complex.  As of June 2007, the Refuge, The Nature Conservancy, and River Partners had planted 117,235 blue elderberry (Sambucus mexicana) bushes, which are habitat for VELB, on 4,814 acres (1948 hectares) of riparian and floodplain habitat.  This effort, along with the efforts of other partners, and the discovery of additional VELB populations, has resulted in a recommendation to delist VELB.


A Habitat Protected­ – Vernal Pools.  Many refuges within the San Luis, San Francisco Bay and Sacramento National Wildlife Refuge Complexes contain special wetlands called vernal pools.  They are seasonally flooded depressions in impermeable soils that hold rainwater until evaporation.  The pools are home to specialized plants and animals adapted to this wet/dry regime.  As the pools dry during summer months, concentric rings of colorful flowers grow in halos around pool edges.  These self-contained ecosystems are home to several listed species, including tiger salamanders (Ambystoma californiense), vernal pool tadpole shrimp (Lepidurus packardi), vernal pool fairy shrimp (Branchinecta lynchi) and various plants (e.g., palmate-bracted bird’s-beak, Cordylantus palmatus).    In addition to restoring the natural hydrology of the pools, Refuge staff often use prescribed fire, and carefully-monitored herbicide applications and grazing programs to control invasive species.  All these management actions are contributing to the recovery of listed species that live in the unique vernal pool ecosystems.


A Mouse Relocated.  The salt marsh harvest mouse (Reithrodontomys raviventris) is endemic to the common pickleweed-dominated habitat along the fringes of tidal marshes of the San Francisco Bay estuary.  Over 80% of the marsh habitat around the estuary has been modified or destroyed.  Protection of remaining habitat, along with salt marsh restoration and enhancement, are key to the species recovery.  The efforts of many public and private groups around the Bay Area have resulted in noticeable gains in protecting and restoring the mouse’s habitat. 


One step in the mouse’s road to recovery involved a parcel on the Don Edwards San Francisco Bay National Wildlife Refuge.  Refuge specialists converted agricultural land into salt marsh wetland covered with pickleweed.  Mice were translocated from an off-refuge parcel that was being lost to the development.  After two years, the numbers of mice are remarkable, but some things just don't show up in the cold hard numbers.....such as the several male-female pairs of harvest mice captured in the same trap!  Without going into the scandalous details, let’s just say that the biologists nicknamed trap D-22 the "Honeymoon Suite.”  The translocation of mouse and associated natural re-colonization appear to be successful, and the recovery of the harvest mouse another step closer.


A Species Increased – Light-footed Clapper Rail.  Much of the recent success in the recovery of the endangered light-footed clapper rail (Rallus longirostris levipes) is due to determined efforts of the San Diego Bay National Wildlife Refuge, Carlsbad Fish and Wildlife Office, California Department of Fish and Game, U.S. Navy, Chula Vista Nature Center, SeaWorld-San Diego, San Diego Wild Animal Park, Port of San Diego, local scientists, and volunteers.  Although the species is not out of danger, the population of the rail has risen from just 142 pairs in 14 coastal marshes in southern California in 1984, to approximately 408 pairs in 18 marshes.  A significant step in the recovery of the rail is the development of the captive breeding program and translocation of birds to marshes along the southern California coastline.  The San Diego Bay Refuge plays a pivotal role in this program by providing a location in which young fledglings are acclimated before translocation to receptor marshes. 


Contact Info: Scott Flaherty, , Scott_Flaherty@fws.gov
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