The Mount Diablo Buckwheat One Year Later

Botanists and nature lovers celebrated good news this spring as the Mount Diablo buckwheat (Eriogonum truncatum)—presumed extinct until its rediscovery in 2005—germinated and bloomed for a second year in the wild for and for the first time in carefully-tended greenhouse pots. Prior to its rediscovery in May 2005 by UC Berkeley graduate student Michael Park, the plant had not been seen since 1936. Its reappearance in 2006, both in the wild and in cultivation, affirms that scientists working to maximize its chances for survival are on the right track. While the species remains endangered, this year’s bloom is a hopeful sign for the future.

Photo by Scott Hein

The “surprisingly dainty” Mount Diablo buckwheat, presumed extinct for 69 years, was rediscovered in May 2005 by UC Berkeley graduate student Michael Park, seen above at the site posing with one of the precious plants. Photos by Scott Hein.

Within a month of the Mount Diablo buckwheat’s rediscovery last year, a group of experts convened as the Mount Diablo Buckwheat Working Group to develop plans for preserving and managing the plant. Led by Cyndy Shafer, an environmental scientist for California State Parks, the group includes representatives of the UC Botanical Garden at Berkeley, California Department of Fish and Game, California Department of Parks and Recreation, California Native Plant Society, Save Mount Diablo, UC Berkeley Jepson Herbarium, and U.S. Fish and Wildlife Service, along with researcher Michael Park. The Working Group developed an Interim Management Plan, recommending a conservative approach until more is known about the plant, its preferred habitat, and its response to various environmental conditions.

From the time of the Mount Diablo buckwheat’s rediscovery, the Working Group has focused primarily on understanding the characteristics of the site where the plant was found; propagating the plant in a nursery setting; surveying other, similar areas for possible additional populations; and monitoring the one known population in the wild.

The Mount Diablo buckwheat is a diminutive annual wildflower that completes its entire life cycle in a period of just a few months in spring and summer. Since the plant dies after setting seed, the germination of those seeds in following years is critical to its long-term survival. To protect the plants from disturbance and help insure seed set, the Working Group installed chicken wire cages over the two main clusters of seedlings in June of 2005. As further protection, the group severely restricted access to the site. Once seed from the 2005 plants dropped onto the ground, the scientists collected it from under at least five different plants for long-term storage and propagation.

The Working Group sent most of those seeds to the National Center for Genetic Resources Preservation (NCGRP) in Fort Collins, CO, which stores seeds of endangered species to preserve their genetic diversity until they can be reintroduced into native habitats. John Domzalski, plant propagator at the UC Berkeley Botanical Garden, sowed the remaining seeds in pots in a greenhouse at the garden. With information about the soil where the Mount Diablo buckwheat was found and the growing requirements of related species, he developed a soil mix and additional treatments to create the best possible growing conditions for the seedlings. His efforts were successful: twelve seeds germinated this May and grew into robust, healthy plants that flowered in early June. In fact, these plants are larger and bear more and larger flowers than the plants in the wild. Later this summer, scientists will collect seeds from the greenhouse plants. Again, some will be sent to the NCGRP for storage and the rest will be sown in pots at the garden in the fall.

Holly Forbes, Curator and Conservation Officer for the Botanical Garden, noted the fundamental importance of growing the plants in a nursery setting. “Conservation efforts on behalf of rare plants depend in large part on our learning to grow them in cultivation to reproductive maturity. Success in achieving seed set in cultivation takes the burden off the natural population for attempts to create additional populations in the wild.”

At the same time, growing plants exclusively in a nursery for many successive generations may inadvertently favor individuals that are genetically better-suited to greenhouse conditions than to those in their native habitat. So the Working Group hopes to introduce seeds into the wild from the second greenhouse crop to preserve as much of the plant’s genetic diversity and environmental adaptability as possible.

The 20 buckwheat plants Michael Park found in May 2005 were growing on a remote slope, spread over a narrow band of about 25 square feet. They had germinated in relatively bare soil above a zone of chaparral shrubs and below a larger area carpeted by invasive non-native grasses. Disturbance may be an important factor in the survival of the buckwheat, as it seems to prefer open ground to grow and thrive. That disturbance might take the form of scurrying rabbits feeding on grasses at the edge of the chaparral, small soil particles rolling down the slope, trudging cows tearing openings in the invasive grass cover, or other events that open bare ground in which the buckwheat seedlings can germinate and grow.

About 90 Mount Diablo buckwheat seedlings emerged at the same location this spring, several times more than in 2005 but clumped together more closely. In general, all of the plants are smaller than last year’s, with fewer flowers per plant and, in spite of the larger number of plants, fewer flowers overall than last year. One of many possible explanations for smaller plants and fewer flowers is the increased competition for water and nutrients among the more closely-clumped plants. It is likely that this year’s plants will produce less seed than last year’s.

The Interim Management Plan includes provisions for continued monitoring of the wild Mount Diablo buckwheat population. In spite of its return to the rolls of living plants, this species is still critically endangered and its existence depends on the survival of one small population that is vulnerable to any number of natural threats, such as landslides and competition from non-native grasses.

The Working Group also hopes to plant seeds collected from the Botanical Garden’s 2007 crop in other suitable locations near the current population and possibly at other Mount Diablo sites to establish new populations. In addition, now that the plant’s habitat requirements are better understood, the group will ask local botanists to search for as-yet-unknown populations of the Mount Diablo buckwheat in other parts of the park.

In Mary Bowerman’s early days of surveying the plants of Mount Diablo, the state park consisted of fewer than 7,000 acres. Now, Mount Diablo State Park and other surrounding parks encompass more than 83,000 acres of protected land. In fact, the site where the Mount Diablo buckwheat was rediscovered is on land acquired and donated to the state park by Save Mount Diablo, the organization Mary Bowerman co-founded in 1971. Rediscovery of the Mount Diablo buckwheat has brought the preservation movement full circle from Mary Bowerman’s 1930s survey to preservation of new land to rediscovery of the endangered plant on that preserved land.

“The Mount Diablo buckwheat is a Bay Area treasure,” said Cyndy Shafer, the leader of the Working Group. “The plants may be small, but they demonstrate the immense importance of protected lands in preserving biological diversity. Mount Diablo can be seen from 200 miles away, but the impact of this conservation success story inspires people all around the world.”

If you would like to know more about the Mount Diablo Buckwheat and the effort to protect it, contact Cyndy Shafer at cshaf@parks.ca.gov or (707)769-5652 ext. 208.