Rare Plant Research

In early 2020 the last showy Indian clover plants were transplanted. They are being monitored, and data is being analyzed to see if this population will persist after reintroduction.

Parks staff continues ongoing evaluation of all the rare plant populations at Ring Mountain, supporting researchers who study these species. Research findings then inform management of Ring Mountain Preserve, including strategies for supporting these unique species and their habitats.

With native grasslands and serpentine soils, Ring Mountain is home to a variety of rare and endangered plant species.  Serpentine soil, with high concentrations of heavy metals and low concentrations of essential nutrients, gives rise to plants that adapt to survive here and cannot live in other conditions.

Research focuses on three plant species:

• Discovered in 1971, the federally threatened Tiburon mariposa lily (Calochortus tiburonensis) grows here in serpentine soil, and nowhere else.
• With only two isolated wild populations, Tiburon jewelflower (Streptanthus glandulosus niger) is a serpentine annual on the brink of extinction.
• Once prolific in the North Bay, showy Indian clover (Trifolium amoenum) was last documented on the serpentine slopes of Ring Mountain in 1961.

Research efforts include:

• Monitoring Mariposa lilies on the hilltop, to study the plant's ability to enter dormancy for many years in unfavorable climatic conditions.
• In 2017, researchers transplanted Tiburon jewelflower in two locations on Ring Mountain.
• In 2018, scientists reintroduced showy Indian clover to see if it can grow and flourish.

Since 2011, the Marin County Open Space District has collaborated with the Nature Conservancy on preserving Ring Mountain. Join a volunteer workday to help remove invasive species, collect seeds, or install native plants. Kids ages 5 and up are welcome with an adult. Check the calendar for Ring Mountain volunteer opportunities.

• Manage invasive plant species.
• Monitor and manage rare plants.
• Restore native plants to areas where invasive plants have been removed.
• Partner with local organizations to educate and involve the community in stewardship.

• Nature Conservancy
• Assistant Professor of Biology at Mills College, Sarah Swope, PhD
• California Native Grasslands Association Diana Jeffery, PhD
• Marin Master Gardeners
• U.S. Fish and Wildlife Service (USFWS)
• Many individuals and organizations who have donated time at volunteer workdays.

In May 2018, the Marin County Board of Supervisors signed off on a $240,000 Nature Conservancy grant to help support the Ring Mountain Stewardship and Habitat Restoration Program through early 2021.

The USFWS supported showy clover reintroduction research with grants totaling $36,837.