The purpose of this Biological Diversity Baseline Report for the Lawrence and Barbara
Daley Preserve is to provide the County of San Diego with information on existing
biological conditions to assist in the development of Area Specific Management
Directives. The approximately 597-acre1 Preserve is located in the south central portion
of San Diego County, in the community of Dulzura, north and east of Highway 94 and
south of Honey Springs Road. Technology Associates International Corporation
(Technology Associates) assisted by the San Diego Natural History Museum, conducted
baseline biological surveys at the Preserve on behalf of the County of San Diego
Department of Parks and Recreation.
Baseline surveys were conducted in the winter, spring, and summer of 2009-2010.
Biologists conducted the following surveys to assess the current status of biological
resources onsite: (1) mapping of vegetation communities, (2) a floral inventory including
rare plant surveys, (3) butterfly inventory surveys, (4) pitfall trapping for amphibians,
reptiles, and small mammals, (5) arroyo toad surveys, (6) aquatic herpetofauna surveys,
(7) diurnal avian point count surveys, (8) nocturnal avian surveys, (9) acoustic bat
surveys, (10) small mammal trapping, and (11) track and camera station surveys for
medium and large mammals. Due to the 2007 Harris fire that burned all of the Preserve,
results of these surveys may under-represent the diversity of plant and wildlife species
that occupy the Preserve.
Ten vegetation communities were mapped within the Preserve and consist of Diegan
coastal sage scrub, coastal sage-chaparral scrub, southern mixed chaparral, native
grassland, non-native grassland, southern riparian woodland, coast live oak woodland,
eucalyptus woodland, disturbed habitat, and urban/developed habitat. The most abundant
vegetation community on the Preserve is Diegan coastal sage scrub, which makes up
approximately 417.20 acres or 70% of the total area. Floristic surveys documented 355
plant taxa occurring on site. These include both native and non-native species along with
eleven sensitive (California Native Plant Society List 1-4) plant species, including: desert
fragrance (Ambrosia monogyra), San Diego needlegrass (Achnatherum diegoensis),
Palmer's sagewort (Artemisia palmeri), San Diego sunflower (Bahiopsis [Viguiera]
laciniata), delicate clarkia (Clarkia delicata), Palmer's goldenbush (Ericameria palmeri
var. palmeri), chocolate lil
This review prioritizes infrastructure improvements of 35 existing undercrossings inspected by wildlife experts in the field along 14.6 miles of SR-94 where the highway bisects conserved lands—particularly between the San Diego National Wildlife Refuge (SDNWR), where a box culvert has been designed specifically for this undercrossing, between Rancho Jamul Ecological Reserve (RJER) and Hollenbeck Canyon Wildlife Area (HCWA), and between Bureau of Land Management (BLM) lands and the Lawrence and Barbara Daley Preserve (LB Daley). In total, SR-94 crosses >10 miles of conserved lands with only three bridges—at the Sweetwater River, Dulzura Creek, and Campus Grove bridge in Dulzura. Following is a summary of improvements recommended for existing undercrossings and proposed new undercrossings, by segment, presented in this document.