Focused Rare Plant Surveys of the Alameda Watershed

Nomad Ecology conducted focused botanical surveys for forty special-status plant species that were determined to have the potential to occur within the Alameda Watershed. To capture the blooming periods of these forty special-status plant species, a compilation of information from online herbaria specimen data were evaluated to determine the average month of peak flowering phenology. Based on this evaluation, surveys were conducted during the months May and June of 2009 to capture as many of the applicable blooming periods. Surveys were also continued in the months of March and April 2011 when additional funding became available.

Due to the size of the Watershed, survey locations were stratified within the watershed to target suitable habitat from least to most disturbed with regard to native vegetative integrity. Survey tiers were based on existing grazing leases within the watershed and were determined by a general evaluation of the level of weediness, intensity of cattle grazing, presence of ultramafic and heavy clay substrates, extant special-status plant populations, land-use, etc.

During the focused botanical surveys conducted within the Alameda Watershed, a total of 514 plant species were observed within the areas surveyed. Eight plant species listed by CNPS were observed within the areas surveyed during the course of focused botanical surveys: chaparral harebell (Campanula exigua), Congdon’s tarplant (Centromadia parryi subsp. congdonii), Hospital Canyon larkspur (Delphinium californicum subsp. interius), Santa Clara thorn-mint (Acanthomintha lanceolata), Santa Clara red ribbons (Clarkia concinna subsp. automixa), Jepson’s woolly sunflower (Eriophyllum jepsonii), stinkbells (Fritillaria agrestis), and serpentine leptosiphon (Leptosiphon ambiguus). A total of 141 plant species considered locally rare were observed within the survey areas of the Alameda Watershed.

Upon completion of the focused surveys, Nomad prepared a technical report, which included a description of the methods used, the numbers, size, and condition of all listed species observed, potential threats to these populations, photographs of special-status plant populations encountered, and a plant list of all species encountered during the surveys. The report included maps that identified the locations special-status plant species found on site. Nomad gave presentations to SPFUC staff summarizing the results of the focused botanical surveys.

LOCATION: Mount Hamilton Range, Alameda and Santa Clara Counties
CLIENT:San Francisco Public Utilities Commission

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