San Diego Management & Monitoring Program






Lead author: Ellen Bauder
Current SDecies Status: This plan addresses six vernal pool species that are listed as endangered and one that is proposed for threatened status: Eryngium aristulatum var. parishii (San Diego button-celery), Orcuttia calfornica (California Orcutt grass), Pogogyne abramsii (San Diego mesa mint), Pogogyne nudiuscula (Otay mesa mint), Riverside fairy shrimp (Streptocephalus woottoni), San Diego fairy shrimp (Branchinecta sandiegonensis), and Navarretiafossalis (spreading navarretia). Pogogyne abramsii was listed as endangered on September 28, 1978. Pogogyne nudiuscula, Orcuttia ca1~fornica, Eryngium aristulatum var. parishii, and the Riverside fairy shrimp were listed as endangered on August 3, 1993. The San Diego fairy shrimp was listed as endangered on February 3, 1997. Navarretia fossalis was proposed for listing as threatened on December 15, 1994. Historically, San Diego, vernal pool habitat probably covered no more than 6 percent ofthe county, approximately 520 square kilometers (200 square miles). Currently levels estimate a loss of vernal pool habitat in the San Diego County around 95 to 97 percent because ofintensive cultivation and urbanization (Bauder and McMillan 1998). Lack ofhistorical dataprecludes the same depth of analysis for Los Angeles County, Riverside County, Orange County, or San Bernardino Counties, but losses are considered nearly total (USFWS 1993). The current distribution ofpools in northern Baja California, Mexico, probably comes much closer to the historic condition (Bauder and McMillan 1998). Habitat Requirements and Limiting Factors: Following winter rainstorms, vernal pools form in depressions above an impervious soil layer or layers. Water evaporates from these pools during the spring and early summer. Vegetation communities associated with adjacent upland habitats that surround the vernal pools in southern California are valley needlegrass grassland, annual grasslands, coastal sage scrub, maritime succulent scrub, and chaparral. iii Prior to 1945, the primary threats to southern California vernal poois were grazing. water impoundments, and conversion to agriculture. In recent years, urbanization and construction of infrastructure have resulted in losses of habitat estimated to be as high as 97 percent. Urbanization can directly impact pools through elimination of the habitat by soil alteration, vegetation alteration, alterations in hydrological regimes, and water quality. Where pools remain th

2010 Vernal Pool And Quino Habitat Restoration Project Implementation Report report

PROJECT OVERVIEW Vernal pool habitat in southern California, and specifically southern San Diego County, has been greatly diminished as a result of extensive development throughout the region. The value and function of remaining vernal pool habitat continue to be degraded by development-related disturbances such as trespassing, grazing, and invasion of nonnative species. As a result, the sensitive species that are supported by vernal pool habitat are also at risk: San Diego fairy shrimp (Branchinecta sandiegonensis), Riverside fairy shrimp (Streptocephalus woottoni), and Quino checkerspot butterfly (Euphydryas editha quino; Quino), which are all federally endangered species, as well as the federally and state listed San Diego button-celery (Eryngium aristulatum var. parishii) and the federally threatened spreading navarretia (Navarretia fossalis). To halt the decline and stabilize the vernal pools in San Diego County, and restore habitat function and sensitive species populations, restoration and management actions are necessary. The City of San Diego (City), in cooperation with other coordinating agencies such as the County of San Diego (County), San Diego Association of Governments (SANDAG), U.S. Fish and Wildlife Service (USFWS), California Department of Fish and Game (CDFG), and California Energy Commission (CEC), obtained grant funding1 to protect, restore, and manage portions of the remaining vernal pool habitat in southern San Diego County. AECOM (formerly EDAW, Inc.) was retained by the City to conduct a comprehensive assessment of existing vernal pool sites within the jurisdiction of the City and County, develop and prioritize recommendations for restoration and management of those sites, and implement restoration and management of the sites. This report summarizes the results of implementation of the restoration and management recommendation actions at five key vernal pool sites in the County, as shown in Figure 1 (Nobel Drive, Goat Mesa, Otay Lakes, Proctor Valley, and Marron Valley). More detailed maps of each site are provided in Figures 2 through 6. Chapters 2.0 through 6.0 of the report correspond to a specific site. Within each of these chapters, a description of the restoration and management actions undertaken at the site are included (i.e., dethatching, weeding, reseeding, recontouring of vernal pools, installation of artificial burrowing owl burrows, and/or access control). A summary of the site condition foll