I remember the first time I visited Black Diamond Mines Regional Preserve, situated between Mount Diablo and Antioch, on a hot September day in 1978. The spiky expanse of wild oats covering the sunbaked hills seemed a particularly striking example of exotic plants’ invasion of California grasslands. If someone had told me then that the preserve would produce one of the next century’s most amazing native wildflower discoveries, I’d have been, well, amazed.
When I visited during the cool of February 2017, it seemed a likelier setting for the romance of botanical exploration. The landscape brought to mind Victorian paintings of California as an earthly paradise: sunbeams rayed through diaphanous clouds; greenswards swept to oak-studded hills. My botanical explorer guides, Heath Bartosh and Brian Peterson, weren’t focused on greenswards, however. They were looking for steep patches of bare soil.
Sighting two particularly steep and muddy patches, they gravitated toward them so fast that it seemed a kind of levitation (which would be a useful skill in seeking the needle of a rare plant in the haystack of a landscape). When I caught up with them, Bartosh pointed at something in the mass of exotic weed seedlings that winter rains had sprouted around the bare patches’ borders.
“They’re here,” he said. I looked closer and saw, among the weeds, seedlings of a plant that has been called the “ivory-billed woodpecker”—a bird presumed extinct—of rare and threatened native wildflowers. It was Mount Diablo buckwheat, an annual forb that is found only in part of the East Bay, and that has been found only a few times in the past two centuries.
Bartosh and Peterson, both professional botanists, hadn’t expected to find it at Black Diamond Mines. Hired by the East Bay Regional Park District to conduct a rare plant survey of the preserve, they’d been looking for endemic globe lilies and manzanitas one hot day in May 2016, when they’d spotted a pink haze emanating from a canyon side. A closer look had revealed myriad “cotton candy” blossoms of plants that looked like Mount Diablo buckwheat, and that turned out, after due examination and consultation, to be Mount Diablo buckwheat. “It was,” Bartosh said, “the find of a career.”
To me, seeing the plant in February was a bit of an anticlimax at first. Although I’d heard a lot about the species, Eriogonum truncatum, I hadn’t seen a live specimen, and the photos I’d seen had been of mature plants prettily blooming. I’d anticipated something more special-looking than these minuscule seedlings among the weeds, which looked not unlike other seedlings of the buckwheat genus Eriogonum that I’d seen, their leaves radiating from the ground like pointy reddish-green teaspoons.
But if the seedlings’ appearance wasn’t that impressive, something else about them was. Although I’d seen the botanists’ estimate that as many as 1.8 million Mount Diablo buckwheat plants grew there in 2016, I’d been skeptical. Recent earlier discoveries had recorded far fewer plants. But when Bartosh and Peterson directed my eye from the weeds to the bare patch itself, I saw that a kind of emerald glaze hovering over its brown surface was composed of countless Mount Diablo buckwheat seedlings, a truly astounding number of tiny plants, mostly growing from crumbling mud.
I still couldn’t quite believe my eyes at the sheer abundance of them, and I think the two botanists may have felt a little incredulous too, perhaps accounting for their rapid levitation to the bare spot when we arrived. They hadn’t been back since the 2016 plants seeded and died in September. The past spring’s pink haze may have begun to seem like something in a dream. “I had personally hoped to find this thing for so many years, and then I suddenly walk up to this population that was so numerous,” Bartosh said when the discovery was announced. “It was like, wait a minute, this can’t be real.”
When I looked up from the emerald glaze, the botanists had disappeared again. When I caught up with them, they were discussing the mystery of the species’ very restricted distribution. Miles of steep ridges separate the Black Diamond Mines rediscovery site from the handful of locations where the plant has been found growing in the past two centuries; little is known about how it spreads. Although its seedlings teemed among the weeds at the bare spots’ edges, I’d found none growing a few steps away. How does the species perform its own kind of levitation, appearing and disappearing from place to place?
The botanists were considering the possibility of water distribution, whereby seeds carried into a stream by landslide might wash downstream to another landslide, which they’d then colonize. There were several new landslides on the bare spots: one had carried down a tree. But since the botanists hadn’t found any Mount Diablo buckwheat plants growing downstream (or upstream) from the Black Diamond Mines site, this was still a theory, one of a number provoked by the mysteries of what I began to think of as “little big plant.”
The fundamental mystery of Mount Diablo buckwheat is this: How has such a rare endemic survived the past two centuries of huge ecological change, not to mention the past millennia’s shifts of climate and geology? The mystery has grown as some of California’s most colorful and influential botanists have encountered the species.
William H. Brewer probably wasn’t particularly mystified when he discovered it near Marsh Creek east of Mount Diablo on May 29, 1862. As botanist for the Whitney Geological Survey, which first scientifically described the state, he found many new species, and his chief concern was locating mineral deposits like the Black Diamond Mines coal. Mary Katharine Curran, botany curator at the California Academy of Sciences, most likely knew of its specialness when she collected the species at an Antioch location in 1886. She had just met a plant explorer named Townshend S. Brandegee, whom she soon married; they honeymooned by hiking through half the state collecting plants, a collection that grew to over 76,000 specimens and became the core of the herbaria at UC Berkeley.
In 1903, a Stanford graduate student, Charles F. Baker, described the species as locally common on rocky banks along Marsh Creek. Then it didn’t turn up again in botanical collections until the 1930s, when another California Academy botany curator, John T. Howell, found it on Marsh Creek, and a UC Berkeley graduate student, Mary L. Bowerman, found it in what is now Mount Diablo State Park. Bowerman was well aware of its specialness since she was conducting the first ecologically oriented study of the mountain’s vegetation. She later helped to start Save Mount Diablo, a nonprofit organization, which set out to protect the native ecosystem by acquiring land. But she didn’t find the buckwheat again after 1940.
Suspense mounted as it seemed that the species might be extinct. So there was great excitement in 2005 when Michael Park, another UC graduate student, found a small patch of the buckwheat on land that Save Mount Diablo had acquired for the state park. “We’ve been calling the Mount Diablo buckwheat the holy grail for botanists working the East Bay,” exulted Barbara Ertter, curator of western North American flora at UC Berkeley’s University and Jepson Herbaria. “It’s been the number-one priority [the species] we’ve been trying to relocate.” The 2005 rediscovery was national and international news, partly because it coincided with apparent sightings of the charismatic ivory-billed woodpecker. Famous biologist Jane Goodall, among others, hailed the buckwheat news as reason for hope in an “age of extinction.”
Conservationists took pains not to divulge the Mount Diablo site’s location, which might seem overcautious for dealing with a little wildflower that doesn’t look that spectacularly different from the 150 or so other members of its genus. But the 2005 site contained fewer than 20 plants, and rarity has a powerful and not always positive effect on the human mind. Collectors, including scientists, have gone to great lengths to get “last specimens” even when this risked bringing about a species’ demise in the wild. The buckwheat protectors were not eager to be guides to the 2005 site even for this article, which I understand. (To paraphrase one California ex-governor: How many buckwheats do you need to see?)
A collaboration of local, state, and federal agencies, nonprofits, and scientists, the Mount Diablo Buckwheat Working Group (MDBWG), has been trying to solve the survival mystery since 2005. I talked about what they’ve learned with Holly Forbes, curator and conservation officer at the UC Botanical Garden, who has assumed the task of propagating the species and preserving its genetic material. She said Mount Diablo buckwheat has proved “very easy to grow” at the garden. She even calls it, affectionately, a “nursery weed.”
The species needs no “special nutrient formula” to grow in, she says, and the seeds don’t seem to have any special dormancy requirements. The tiny white or pink flowers don’t seem to have special pollination needs either. They open in the daytime, and “if something pollinates them, fine.” If nothing does, they self-pollinate when closed at night. Each flower produces a single tiny seed: I first thought one that Forbes showed me was a speck of dust. But each plant produces many flowers, so propagating seeds in the nursery has not been a problem.
Maintaining the 2005 buckwheat population in the wild has proved more complicated. I talked about that with Cyndy Shafer, a state parks senior environmental scientist who coordinated the MDBWG from 2005 to 2016. “Our focus in the past 12 years has been on preserving the species and providing some insurance for it,” she said. “It’s not easy with an annual whose yearly populations are so fleeting.” So far, attempts at reseeding with nursery-produced seeds have been disappointing. In 2015, sowing 80,000 seeds at one experimental site produced just hundreds of new plants. This year the scientists will learn more about the sustainability of that reintroduction, as well as the two wild populations.
“We’re hopeful,” Shafer said. “This will be a telling year for us, since all the rain suggests it will be an extended spring.”
Solving the survival mystery will entail learning more about the species’ life cycle in its natural habitat. Michael Park’s 2005 rediscovery site is at an interface between chaparral and grassland. Mary Bowerman noted that the species grew with shrubs like poison oak and California sagebrush but also with grasses like brome. A zone of bare soil often lies between chaparral and grassland, which would seem favorable to a small native wildflower that has trouble competing with aggressive weeds.
Botanists once thought that chaparral shrub roots produce toxins that inhibit grassland plants from growing near them, but studies of the shrubs didn’t corroborate this. Then it seemed possible that small browsers hiding from predators in chaparral, brush rabbits and such, might cause the bare soil zone by cropping the weeds, thus allowing native plants to grow. But camera traps at the 2005 site didn’t reveal much brush rabbit activity, although they did photograph many quail, also browsers on seeds and seedlings. More needed to be learned.
Then along came the 2016 Black Diamond Mines rediscovery. “It was like, whoa!” Holly Forbes told me, “so many plants of all sizes just in a square foot…It was astounding! It was hard to wrap our heads around.” The find complicated what had been a satisfyingly dramatic narrative: sharp-eyed researcher finds species feared lost: conservationists rush to snatch a few remaining specimens from the jaws of extinction. But the little troop of “E. truncatum’s last stand” suddenly became a big army, albeit a bewilderingly localized one. Official and media response was more muted than in 2005.
“Finding the Mount Diablo Buckwheat in Black Diamond Mines Regional Preserve is exciting,” said Matt Graul, the East Bay Regional Park District’s chief of stewardship, in a September 2016 MDB Working Group media release. “Both locations of the plant [2005 and 2016] are tiny and on steep slopes that could be easily damaged. A fire or a landslide might completely wipe out one or both of the populations.” Seth Adams, land conservation director of Save Mount Diablo, struck a similar cautionary note. “On the one hand a second location is good news, but it could be dramatically affected by east county development pressure. Right now, for example, Antioch is considering plans for more than 4,000 houses.”
Heath Bartosh showed me a stark sign of development pressure as we were coming back from looking at the seedlings in February. He pointed to a wire fence that crossed one of the greenswards. “That’s the urban growth boundary,” he said. “There’s housing proposed for the other side of that fence.” And there are other kinds of pressure. When I asked Bartosh if potential flower thieves had tried to wheedle the 2016 site’s location out of him, he said that indeed they had.
The 2016 site is good news for the species, of course. “The Antioch population is a great discovery,” Holly Forbes said in the MDBWG’s September release. “Its habitat is quite different from the 2005 rediscovery site and provides valuable information for efforts to develop new populations.” Bartosh said in the same release that the site more resembles the “highly erosive” dry hillsides where Brewer first found Mount Diablo buckwheat than the 2005 site’s chaparral-grassland interface.
When I asked Forbes what she thought might be learned from the new site, she said its huge number of plants would help greatly in studying things like the species’ genetic variation, which could provide insight into how the species evolved and adapted to its present habitat. She still seemed mystified by the 2005 site’s difference from the Black Diamond Mines one, where she’d been able to gather thousands of seeds during a single visit. When I asked if she had any ideas about how the species could grow in such apparently divergent habitats, she said she didn’t really, but that Michael Park might. When I contacted Park, however, he replied that the two sites aren’t in “truly diverging habitats,” adding that “the common denominator is slope instability.”
There’s certainly irony in little big plant’s sudden population jump from fewer than 20 individuals to over a million. Anti-environmentalists might point to that as proof of the futility of spending money and effort to save apparently vanishing species. But I think it is actually proof of that method’s efficacy, because Mount Diablo buckwheat’s 2016 rediscovery occurred where money and effort have been spent to save species. It was rediscovered because the site is protected. The same is true for the 2005 rediscovery site that incited comparison with the ivory-billed woodpecker. (Unfortunately, the reported ivory-billed sightings proved inconclusive; no one could verify it was the right species.)
Michele Hammond, an EBRPD botanist who hired Bartosh’s company, Nomad Ecology, and who now coordinates the MDBWG, is enthusiastic about E. truncatum’s prospects. “This has been a super-exciting example of the benefits of land use planning,” she told me. “As more land is protected, we’ve been able to look at more places and think about their botanical potential, then take advantage of Heath and Brian’s expertise and send them on a rare plant treasure hunt.”
Hammond added that although Mount Diablo buckwheat’s two known current occurrences are in separate areas, they are increasingly linked by corridors of protected land, so that “we hope the species can continue to do its thing even if we don’t understand yet how it does it. And having land corridors in protected status allows us to manage them to the extent that we do know what’s good for rare natives.”
Hammond was touching on one of the main “age of extinction” issues—what is called the “island effect.” As much as we still need to learn about rare species conservation, we have established that if a rare organism lives in an isolated area, or even in multiple isolated places, the prospects for its long-term survival are not good. Populations often die out locally, and if there isn’t “recruitment” from elsewhere, that can be the end for a population and eventually for a species. Linked corridors allow populations to shift around as they have evolved to do in the wild—and especially in grasslands—which boosts survival prospects, although it’s hard to say how much connection is enough.
For all the uncertainties of rare species conservation, I think little big plant’s latest rediscovery demonstrates one thing clearly: Given enough space, the natural resilience of what might seem to be “loser” species is also reason for hope. After all, they’ve been surviving a long time. Mount Diablo buckwheat isn’t the only “species of concern” that responded amazingly to 2016’s favorable climatic conditions. I’ve been walking past a muddy old livestock pond at Mount Diablo for years without seeing amphibians. It dried up entirely from 2013 to 2015. But after the 2016 rains filled it, I found Pacific chorus frogs, western toads, and (endangered) California red-legged frogs breeding in it. When I walked past this spring, the frogs were back, sunning on the spiky weeds by the water.
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The Mount Diablo Buckwheat disappeared in the 1930s. It was thought to be extinct. A single population was rediscovered in 2005. And then last year botanists found a new population numbering in the millions. How has this rarest of rare plants survived?
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