This Integrated Weed Management Plan (WMP) was developed for the City of San Diego Public
Utilities Department to devise an adaptive, comprehensive plan that locates, identifies,
quantifies, prioritizes, and provides recommendations for invasive weed species management
within the approximately 7,405-acre San Pasqual Valley Weed Management Area (WMA). It is
the intent of this WMP to be adaptive, flexible, and responsive to changing site conditions on an
annual basis, including discovery of new invasive species not yet present or known to be
growing in the WMA. The landscape scale plan complements regional land management
objectives and will utilize the management levels and strategies articulated in the Management
Priorities for Invasive Non-native Plants: A Strategy for Regional Implementation (SANDAG
2012). Public Utilities can emulate the WMP at other sites.
The Safari Park Biodiversity Reserve is one of the last remaining strongholds for coastal cactus wrens in
San Diego County, and the cactus scrub supports the greatest abundance of cactus wrens in San Pasqual
Valley. The 2007 Witch Creek fire damaged much of the cactus scrub at the Safari Park and throughout
the San Pasqual Valley. In 2010, we were awarded a TransNet grant to support and enhance the survival
of coastal cactus wrens in the Valley using a strategic, multi-faceted approach. Specifically we proposed
to: (1) construct a cactus propagation and salvage center that will serve as a long-term resource
providing native cacti materials for restoration projects throughout the North County; (2)
collect/propagate over 1,200 prickly-pear cacti per year for restoration in the San Pasqual Valley
(including the Safari Park Biodiversity Reserve and partner-managed MSCP lands); (3) enhance 45 acres
within the Safari Park Biodiversity Reserve through cacti enrichment plantings; (4) monitor
establishment and growth of planted cacti; and monitor cactus wren abundance, distribution, and
habitat use in relation to habitat characteristics and enhancement efforts.
Develop and begin initial implementation of a subwatershed-level
management plan to restore and manage native habitat to support a stable, resilient Coastal
Cactus Wren population in the San Pasqual Valley/Lake Hodges region of the San Dieguito
Watershed. To accomplish this goal, activities have been divided into a series of Tasks and
Phases to be implemented over a two-year period.
The primary goal of this three-year project was to support the restoration and recovery of coastal cactus wren (CACW) populations in the San Pasqual Valley/Lake Hodges region including locations identified under coordination with the South San Diego County Coastal Cactus Wren Conservation Implementation Plan. In pursuit of this goal, the San Diego Zoo Institute for Conservation Research aspired to accomplish two tasks: 1) establish and maintain a cactus nursery to supply cacti for habitat restoration to land managers in North County and 2) control invasive species and restore habitat in potential cactus wren nesting habitat.
The Ramona Grasslands host a unique assemblage of resources:
? The southernmost population of the endangered Stephens? kangaroo rat;
? Unique vernal wetlands that support endangered San Diego fairy shrimp and several rare plant species;
? Santa Maria Creek and associated habitats are important for neotropical migrant songbirds and the endangered arroyo toad; and
? A diverse raptor community, including the largest population of wintering ferruginous hawks in San Diego.
Oak savannah, riparian woodlands, alkali playas, native perennial grasslands, and rock outcrops contribute to the diversity and ecosystem functions within the grasslands. These resources are imminently threatened by the indirect impacts of urbanization and thus require science-informed monitoring and management to ensure their persistence.
The Ramona Grasslands comprise a significant portion of the Santa Maria Creek subbasin of the San Dieguito River watershed. The Santa Maria Creek, which drains the urbanizing community of Ramona, flows westward through the grasslands, then through Bandy Canyon to its confluence with Santa Ysabel Creek. Below the confluence, the San Dieguito River flows through San Pasqual Valley into Lake Hodges, a City of San Diego drinking water reservoir. The creek corridor serves as both a hydrological and habitat linkage for numerous species. It also provides essential ecosystem processes, such as natural filtration of anthropogenic contaminants that may impair downstream water quality.
The Ramona Grasslands Preserve functions as a core habitat area within a regional network of existing and anticipated conservation lands. The coastal sage scrub, chaparral, and oak woodlands of the surrounding landscape, together with the grasslands, riparian habitat, and vernal wetlands of the core area, constitute an exceptional concentration of regionally and globally significant resources. That significance is reflected by the near complete overlap of the Preserve area by federal Critical Habitat designations (San Diego fairy shrimp, arroyo toad, and California gnatcatcher).
The City of San Diego (City) contracted with URS to conduct protocol presence/absence surveys for California gnatcatcher. Nine sites located throughout the City?s MSCP preserve were surveyed to determine presence of California gnatcatcher at each site in spring of 2001. The sites were located at Lake Hodges, San Pasqual Valley, Black Mountain, Los Penasquitos Canyon, Mission Trails Regional Park, Spooner?s Mesa, Otay Mesa/Spring Canyon, Lower Otay Reservoir, and Marron Valley. Gnatchaters were detected at all of the sites.
The San Dieguito River Valley (SDRV), consisting of the San Pasqual Valley and Lake Hodges, is one of the most significant natural open spaces in San Diego County. This area supports a major recreational amenity, the San Dieguito River Park (SDRP), as well as habi-tat for several species covered and permitted by the Multiple Species Conservation Pro-gram (MSCP). The 2007 Witch Fire burned a substantial portion of the SDRV, including more than 60% of the SDRP. The extremely high natural resource and recreational values in this area emphasize the need and urgency for fire recovery efforts.
The primary goal of this three-year project was to support the restoration and recovery of coastal cactus wren (CACW) populations in the San Pasqual Valley/Lake Hodges region including locations identified under coordination with the South San Diego County Coastal Cactus Wren Conservation Implementation Plan. In pursuit of this goal, the San Diego Zoo Institute for Conservation Research aspired to accomplish two tasks: 1) establish and maintain a cactus nursery to supply cacti for habitat restoration to land managers in North County and 2) control invasive species and restore habitat in potential cactus wren nesting habitat.
The coastal cactus wren (Camphylorynchus brunneicapillus sandiegensis) is one of numerous species in decline in San Diego County. Limited to prickly pear (Opuntia.sp.) and cholla (Cylindropuntia sp.) cacti for nesting, the resident songbird's persistence in the county relies upon the existence of such habitat. Urbanization, agriculture, and fire have reduced cactus in San Diego County, leaving only a remnant of the once abundant habitat for the coastal cactus wren (Shuford & Gardali 2008). Large aggregations of cactus wrens exist in areas where urbanization and agriculture have been excluded, such as on the Fallbrook Naval Weapons Station (NWS), on several sites in San Pasqual Valley, and around both Lake Jennings and the Sweetwater Reservoir. Smaller groups dwell in urban canyons, nature reserves, and otherwise undeveloped areas around the county as well. On the order of 200 known coastal cactus wren territories currently exist on public and otherwise preserved properties in San Diego County, likely representing a major reduction from historical population sizes (Shufard & Gardali 2008).
