Recovery Actions for Acanthomintha duttonii Project

Recovery Actions for Acanthomintha duttonii Project

The California Department of Fish and Wildlife is issuing a permit to Creekside Center for Earth Observation [Permit No. 2081(a)-20-020-RP] pursuant to Fish and Game Code section 2081(a) for a project to continue to propagate and seed Acanthomintha duttonii (San Mateo County thornmint) as part of a recovery project that began in 2008. When the project began, there was only one known extant population of Acanthomintha duttonii, located in Edgewood County Park that consisted of 249 individuals. As part of that project, the Permittee introduced seed to the extant population and to five additional sites (four in Edgewood County Park and one on Pulgas Ridge). In May 2020, 43,000 plants were estimated across all six sites (the five introduced populations and the natural population), demonstrating that this project has been highly successful. Under this permit, seed will be collected annually from between 50 to 100 plants, generally in late May, and will be propagated at the Creekside Science Conservation Nursery. Seed collection sites will be chosen annually based on population counts, with the population(s) with the most individuals selected for collection. Seed will be used to continue seeding the current introduction sites and possibly new sites at Edgewood County Park. Additional seeding is not likely at the existing natural population based on poor performance and declining habitat quality resulting from changes in hydrology, but weeding and other management may occur at this population. Areas near the existing natural population (approximately 100 meters away) may potentially be seeded if suitable areas are identified. The Project will also test the effects of a grass-specific herbicide(graminicide) on Acanthomintha duttonii and investigate the effects of reduced nonnative grass cover on the species. Five occupied plots will be treated with graminicide and will be paired with five occupied untreated plots at two or three of the established introduced Acanthomintha duttonii populations each year. Acanthomintha duttonii plants will be counted before treatment and again when plants are mature. A larger buffer that is unoccupied by Acanthomintha duttonii may also be treated (less than 100 square meters per site) to reduce the potential of adjacent nonnative grass seeds moving into occupied areas, as well as to expand potential habitat of Acanthomintha duttonii. Dodder (Cuscuta californica) has been identified as a new threat to Acanthomintha duttonii, and will be pulled by hand, bagged, and removed from each population along with its hosts after Acanthominta duttonii has set seed.

Morgan Hill, Redwood City

San Mateo, Santa Clara

San Francisco Bay Area