By Joe Davitt
In 2017 we made a total of 33 seed collections from plant populations spread across San Diego County. Thirty of these collections entailed populations of species considered rare, threatened, or endangered. As members of the California Plant Rescue (CaPR) initiative our goal is to conserve all of California’s floristic diversity ex-situ, focusing first on the most rare and threatened.These collections included several species that have never before been seed banked by any institution.While many of our seed collections are rare and important, we made several collections from species never previously conserved ex-situ. Our seed collection from Downingia concolor var. brevior represents the first recorded collection from this species. There are just four known occurrences of the species in the mountains of San Diego County, and protecting it ex-situ is a great milestone. We also made two seed collections of Myosurus minimus ssp. apus that represent the first time the species was conserved ex-situ. This Myosurus species is an especially important species to vernal pools in southern San Diego County.
We made 13 seed collections from plant species that are listed as federally endangered, 6 collections from plant species listed as federally threatened, and 2 more from California listed endangered species that are not federally recognized.
14 seed collections came from San Diego’s vernal pool specialists. After great rains in the winter of 2016 and spring of 2017, vernal pools inundated with water, triggering huge population booms of many of our rarest species. Nearly 97% of all our vernal pools have been destroyed as a result of human development, making them one of our most endangered habitats. Vernal pool plant specialists serve as the support system for this fragile ecosystem. Our seed collections provide an insurance plan in case of catastrophe, as well as hope that we can restore and replace some of what has been lost.
We successfully grew an ex-situ population of Dudleya brevifolia from seeds collected from the smallest and most imperiled wild population. Depending on weather conditions, roughly 100 individuals are seen in this small, wild population in any given year. Using seed collected from the population, we successfully germinated and produced 136 individuals growing in our ex-situ population. Many of these individuals matured to flower and produce seeds last year. These seeds can be reintroduced into the wild to help augment the population. Furthermore, these plants are perennials, re-sprouting from corms each spring. This ex-situ population will continue to produce seeds for years to come, ensuring the wild population does not go extinct.
Federally listed endangered species we’ve conserved in 2017:
Chloropyron maritimum ssp. maritimum – Salt marsh bird’s beak
Eryngium aristulatum var. parishii – San Diego button celery
Fremontodendron mexicanum – Mexican flannelbush
Monardella viminea – Willowy monardella
Orcuttia californica – Orcutt’s grass
Pogogyne abramsii – San Diego mesa mint
Pogogyne nudiuscula – Otay mesa mint
Federally threatened species:
Acanthomintha ilicifolia – San Diego thornmint
Navarretia fossalis – Spreading navarretia
California listed endangered:
Downingia concolor var. brevior – Cuyamaca Lake downingia
Dudleya brevifolia – Short-leaved dudleya
Other rare, unlisted species:
Ambrosia chenopodifolia – San Diego bur sage
Brodiaea orcuttiii – Orcutt’s brodiaea
Dicranostegia orcuttiana – Orcutt’s bird’s beak
Dudleya variegata – Variegated dudleya
Lilium humboldtii ssp. ocellatum – Ocellated (spotted) Humboldt’s lily
Myosurus minimus ssp. apus – Little mousetail
Nemacaulis denudata var. denudata – Coastal woolly-heads (cotton-heads)
San Diego County is so diverse. We have coastal beach dunes, salt marshes, vernal pools, deserts, and high elevation pine forests all within an hour drive. The county is home to hundreds of rare plant species, many of which live nowhere else on the planet. We are so excited to be contributing to the conservation of these species and helping to end extinction in this beautiful county!