CitizenInvestor Funds Restoration of San Mateo Thornmint

After a successful fundraising campaign on CitizenInvestor in spring of 2013, and a one year wait for wetter (better) growing conditions for San Mateo Thornmint (Acanthomintha obovata ssp. duttonii), a partnership of groups including County of San Mateo Parks, Friends of Edgewood and Creekside Science carefully seeded around the existing thornmint population in order to expand the limited distribution of this plant.

SMT Dec14 seeding pics-4

Creekside Science, the U.S. Fish and Wildlife Service, and San Francisco Water, Sewer, and Power partnered with the U.C. Berkeley Botanical Garden to produce a seed increase using leftover seeds from a decades-old experiment. In total, 7,500 seeds were dispersed on site and early observations in late December indicate that some germination is already occurring in the newly seeded areas!

SMT Dec14 seeding pics-15

The planting plots were mapped and then prepared by scraping the top 1-2 inches of material to the side creating bare ground. This post-germination scraping technique decreases annual grass cover (for that year) and increases the amount of bare ground, which increases germination (and likely survivorship and seed production also). This treatment increased thornmint numbers and vigor in our previous in-situ experiments.

SMT Dec14 seeding pics-9

Packets of 250 seeds (prepared by the U.C. Berkeley Botanical Garden) were spread as evenly as possible into 30 square-meter plots, then tamped gently into the soil to enhance soil to seed contact.

SMT Dec14 seeding pics-18

The new plots were placed uphill of and adjacent to the existing population, in areas where mowing and dethatching had created the open habitat that favors thornmint. Two of the plots were placed in a historical location where thornmint has not been observed for many years.

120914 SMT seedlings observed onsite

Thank you everyone for contributing to make this a successful project. Creekside Science will continue to monitor germination and maturation of this unique restoration effort.


For more photos and information from the Friends of Edgewood, please read here.

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