Speak of the Devil

The Unexpected Landscapes of Mount Diablo

by on July 01, 2007




I remember spending a night on Mount Diablo during a hot spell in August, 1973. Utterly still in the afternoon’s 102 degree heat, the campsite erupted at dusk with a deafening cacophony of chirps, trills, crackles, hoots, whistles, rattles, and distant howls. A scent of sulfur hung in the air, which stayed hot into the small hours. Daylight’s bucolic setting of picnic tables and barbecue grills had turned into something more like “A Night on Bald Mountain” in Disney’s Fantasia, where a nocturnal peak spews out demons.

Of course, demons were not making the racket; ground crickets, tree crickets, and shield-backed grasshoppers were (accompanied by great horned owls, poorwills, dusky-footed wood rats, and coyotes). But even these harmless insects did seem a bit demonic when I tracked them down in the dark. Waving their improbably long antennae, unperturbed by my flashlight, they just kept on making incredible noise, trying to attract females. I thought of something Thoreau wrote: “Is not the midnight like Central Africa to most?” A half hour’s drive from San Ramon Valley’s bustling suburbs, I seemed surrounded by an array of organisms as untamed and diverse as those in better known and more remote wild places.

The mountain isn’t always as boisterous as it was that night, but there’s usually something interesting happening. Often, the goings-on are surprising. Fence lizards are a common sight on rocks along the trails, but I never expected to see one dive into a creek and swim off downstream like a little alligator, as I did during one wet spring. In another wet year, wading a pool that had flooded part of a trail, I saw what appeared to be dozens of tiny squid suspended in the water. A closer look revealed that they weren’t squid, but something almost as unexpected on usually dry land—fairy shrimp, little crustaceans whose eggs can survive in soil for years until heavy rains re-create the vernal pools in which their short life cycle unfolds. Plants can be surprising here too. I once saw a particularly gorgeous patch of red and blue wildflowers on a ridgetop, and assumed they were California poppies and lupines, the commonest spring blooms. A closer look revealed that two less common plants—wind poppies and Chinese houses—had made a mass of color visible from hundreds of feet away.

Mount Diablo seems to specialize in surprises. “Devil Mountain,” for example, sounds just like what Spanish missionaries might well have named the area’s most conspicuous peak, after an Indian legend. Native Americans did have many stories about the mountain, which they considered a powerful and mysterious place that had played a major part in the world’s creation. The local Miwok tribelet, the Volvon or Bolbones, had a village southeast of the mountain and hunted and gathered acorns on its slopes (the “mortars” they dug into rock formations to grind their crop are still visible in some of the canyons). But they didn’t have permanent settlements on Diablo’s slopes because of its religious significance. And because the mountain is so plainly visible from everywhere in the Bay Area and its environs, many other groups, including the Wintun who lived in the Central Valley to the east, regarded it with reverence and visited it for religious reasons as well.

In the 1700s, the Spanish pioneers Pedro Fages and Juan Bautista de Anza simply named the mountain Cerro Alto de los Bolbones, the Bolbones’ Peak. The present name originated some years later from a surprising mistake. In 1805 or thereabouts, some rebellious Mission Indians escaped from Spanish soldiers in a willow thicket just northwest of what is now Concord. The soldiers dubbed the place “el monte de diablo,” the devil’s woodland, perhaps because they thought the devil had helped the Indians escape, or simply to express frustration. As it happens, monte can mean either woodland or mountain. A Mexican rancho took the name and, somehow, American settlers confused the former meaning with the latter, and started calling the area’s most prominent peak “Monte Diablo.”

Europeans did not originally share the reverence the Indians felt for the mountain. The Spanish, and later the Mexicans, hunted on it and ran their cattle, sheep, and horse herds there as well. By the late 1830s, Americans had begun to acquire large ranches around the mountain, a process that accelerated when the United States took control of California in 1848, and then in 1851 used the summit as the first meridian for establishing property boundaries throughout Northern California. Thereafter, the mountain and its surrounding land was carved into homesteads, orchards, mines, and resorts. Eventually, land speculators hatched plans to cover it with housing subdivisions, as in the surrounding valleys. Fortunately these did not succeed, and today people continue to visit the mountain instead of making their homes on it. This is due in part to the rugged terrain and the growing demand for recreational open space. It is also due to increased recognition of the value of natural diversity and appreciation of the mountain’s role as a refuge for it.

Birth of a Mountain

Mount Diablo is so prominent, dominating its surroundings for miles around, that it is not surprising that it has sometimes been considered an extinct volcano. The wide view from the summit, east to the Sierra Nevada and west to the Farallon Islands, is also typical of a volcanic peak like distant Mount Lassen, visible from the summit on particularly clear days. When geologists first explored the mountain in the mid-19th century, however, they quickly saw that it is not a volcano. “The material of which it is composed is extremely variable in its lithological character,” wrote Josiah Whitney, head of the California State Geological Survey, in 1865, “but it consists essentially of a central portion of very hard metamorphic sandstone.” In other words, Mount Diablo is not a pile of lava and ash erupted directly from the earth, but in large part a slab of ancient Pacific ocean floor (though not primarily sandstone) that has risen above what is now sea level.

How then did ancient seabed rise to Mount Diablo’s present summit elevation of 3,849 feet above sea level? The rocks that Whitney described on Mount Diablo’s summit are components of what is now referred to as the Franciscan Complex, an assemblage that appears at many other Bay Area locations as well. These rocks originated far out in the Pacific during the Jurassic and early Cretaceous Periods, beginning about 200 million years ago. Lava from deep ocean spreading zones mixed with material from the earth’s upper mantle to form the ocean floor. (Outcrops of this lava, called pillow basalts, dot the peak today, and a band of metamorphosed mantle material, a slick blue-green rock called serpentinite, runs along the north sides of the summit and North Peak.) As the predecessor of the Pacific Plate (dubbed the Farallon) inched eastward over the ensuing hundred million years, sediments of the skeletons of marine microorganisms called radiolarians accumulated on the ocean floor and were compressed into sedimentary chert, a flinty rock made up of those siliceous skeletons.

Western whiptail lizard
The Western whiptail lizard is more commonly found in thestate’s southern desert regions, but it is quite at home here along theFire Interpretive Trail near the summit of Mount Diablo. Photo by Scott Hein

Eventually, as the eastward movement of the Farallon Plate carried this assemblage towards the westward-moving North American Plate, sediments of sand and mud eroded from the continent accumulated on top of it. As the two plates collided, and the Farallon Plate was subducted under the North American, some of the rocks were scraped off and accreted onto the western edge of the continent. By about 30 to 25 million years ago, the Farallon Plate had been consumed beneath the North American and replaced at the plate boundary by the northwest-moving Pacific Plate. At the same time, subduction was replaced by a lateral “strike-slip” movement in which the Pacific Plate slid sideways by the North American Plate, as it still does today.

About three million years ago, the relative movement between the plates changed somewhat, adding an element of compression. It is the squeezing of the crust from this compression that has resulted in the northwest-southeast trending faults and mountainous terrain that characterize central California, including the Diablo Range, as some of the rocks between faults dropped down to become valleys, while others rose to become ridges and peaks. As the mountains rose, erosion gradually removed the layers of sediment that had covered older rocks. According to local geologists, Mount Diablo itself did not begin its exceptional uplift above the rest of the range until about 500,000 years ago, making it a virtual infant in the geological time scale.

Faulting activity then began to create another of the mountain’s surprises. A basic axiom of geology is that older rocks underlie younger rocks. But faulting eventually thrust the Jurassic rocks now on Mount Diablo’s summit above remnants of newer rocks that had covered them for millions of years. Most of the rocks on the mountain’s middle slopes originated on the sea floor in the Cretaceous Period, which ended 65 million years ago. Many of the rocks in steep lower canyons, such as the upended fossil-bearing pale sandstone outcrops at Rock City and Castle Rock on the mountain’s southwest side, originated in shallow bays and inland seas between 50 million and 10 million years ago. Still younger Tertiary strata containing bones of mastodons, camels, and other extinct mammals are found in the foothills.

Geologists do not understand exactly why Mount Diablo’s older rocks have risen so far above the surrounding ridges’ younger ones. One theory is that a particularly deep thrust fault underlies it at a depth so great (perhaps ten miles) that it is hard to detect. (Thrust faults are diagonal faults caused by the complex stresses of plate interaction.) This fault may have developed because the unusually massive chunk of Jurassic rock that includes the mountain’s present summit blocked two shallower faults, the Greenville on the southeast and the Concord on the northwest, from connecting across it. The blockage could have displaced the pressures that formed the shallower faults deeper into the earth’s crust, pushing the older rocks up over the younger ones. Erosion then would have removed the top of the upthrust sheet, exposing the Jurassic rocks. (The peak continues to rise at a rate that has been measured at 1 to 3 millimeters a year.)

Such deep thrust faults can hold enormous stress, and are the type suspected of causing large earthquakes, including the disastrous 1994 Northridge quake in Los Angeles. So although it is not a volcano, Mount Diablo may yet be a source of unexpected disturbance someday.

Ecological Crossroads

Science’s explanation of how mountains originate is one of its great achievements. But even science hasn’t exhausted Mount Diablo’s penchant for surprises. Things scientists barely notice at first can turn out to be important. For example, when William H. Brewer, Josiah Whitney’s principal botanical assistant on the State Geological Survey, was exploring the mountain in May 1862, he collected a little pink annual wildflower that he evidently gave little thought to at the time. He didn’t mention it in his writing, except to describe the area near where he found it, east of the peak, as “a flat of perhaps two or three hundred acres surrounded by low rolling hills and covered with oaks here and there, like a park. And such oaks! … one was seven feet in diameter with a head a hundred and thirty feet across.” The little wildflower, with spindly stems from four inches to two feet tall, must have seemed unremarkable in comparison to the massive oak. It was a kind of Eriogonum (Latin for “wooly knees,” referring to the cottony stems), a buckwheat family genus of which there are over a hundred species in the West.

Brewer’s dried specimens were sent east to Harvard, where Asa Gray and Sereno Watson, two of America’s premier botanists, decided the little wildflower was a new species, which they named Eriogonum truncatum in 1871. This probably didn’t surprise Brewer either; he’d found many new species in California, then largely unexplored botanically. But as the state became better known, nobody found Eriogonum truncatum anywhere except near Mount Diablo, and that might well have surprised Brewer. The species, which came to be called Mount Diablo buckwheat, apparently was endemic (meaning it is found nowhere else) to the area, implying, for one thing, that it might have come into existence here fairly recently. “The native plants of California are some of the most exciting in the world,” says a contemporary botanist, Dr. Peter Raven. “Many of them are of recent origin geologically, and the Mount Diablo buckwheat is clearly one of those.”

Indeed, because of its diverse and recently elevated topography, and the climatic conditions arising from that, Mount Diablo is a major center of plant endemism. At least another 11 plant species occur only in the area (including a sunflower, a manzanita, and a globe lily), suggesting that the new conditions caused by its relatively rapid rise over the past half a million years have forced them to evolve and diverge from their more common and widespread relatives. Mount Diablo buckwheat, for example, was found in dry sites, suggesting that it was adapted to the mountain’s lengthening “rain shadow.” Such a situation might give insight into how species in general evolve.

Eriogonum truncatum is unusual even for a local endemic, because it has been Mount Diablo’s rarest and most elusive one. A botanist named Mary Katherine Curran found it near Antioch in 1886, and in 1903 another, named C.F. Baker, found it “locally common along rocky banks” on Marsh Creek Road east of the peak, near where Brewer had collected it. Then nobody seems to have seen it again until the 1930s, when a young botany graduate student at UC Berkeley found some specimens on the slopes of Mount Diablo.

As the student, Mary Leolin Bowerman, later explained, she “hadn’t thought of Mount Diablo as being anything special” when her professor at Berkeley assigned her to study it in 1930. He chose her because she happened to have a car. As she explored the mountain in the ensuing years, however, Bowerman grew fascinated with the beauty and complexity of its plant life. She visited it over a hundred times as a student and collected many hundreds of plant species. In 1932, she surprised her thesis adviser, the eminent botanist Willis Lynn Jepson, by proposing to write her doctoral dissertation on the entire mountain’s vegetation and the way it interacted with the environment. Bowerman approached the mountain’s vegetation not just as an assemblage of plant species to be cataloged individually, but as a system of plant communities, each with typical members and conditions. Such an “ecological” approach to botany was relatively new at the time.

“During my studies, I became more interested in ecology than in straight indentification,” she recalled. “I kept track of which plants were growing together because it was all so completely fresh to me … I soon realized that Mount Diablo is a unique geographical location. It’s part of the inner Coast Ranges yet is subject to coastal influence owing to the absence of high mountains to the west over the Bay. It’s also a pivotal link between the differing vegetation units of the north and south Coast Ranges. The broad variations in temperature, rainfall, wind exposure, and altitude account for its wide variety of plant life.” Completed in 1936, the thesis was expanded and published as The Flowering Plants and Ferns of Mount Diablo, California, in 1944. The book has been a major reference source on the mountain’s botany and natural history ever since.

Bowerman noted that the area’s vegetation had been very different before Mount Diablo arose. Fossils uncovered nearby show that a forest of bald cypress and tupelo, trees still found in today’s Southeast swamps, grew here in the Miocene epoch (23 to 5 million years ago). Some plants typical of that ancient forest remain, deciduous trees like box elder and sycamore, but as the land gradually became drier and hillier, other plants moved in as well, creating the intricate mosaic of life that covers the mountain today.

As it rose dramatically over the past half a million years, Mount Diablo became a kind of ecological crossroads, where, because of its central location and diverse topography, organisms that occur north to the rain forests of British Columbia intersect with species that are also found in the deserts of Mexico. Western pond turtles, red-legged frogs, and varied thrushes like those in Redwood National Park coexist on the mountain with tarantulas, roadrunners, and horned and western whiptail lizards, like those in Joshua Tree National Park. On the September evenings when tarantulas roam in search of mates, the mountain is so dry that it might almost be desert. On the nights in March when red-legged frogs look for breeding pools, it can be so wet that it might almost be rain forest.

The Mountain’s Mosaic

Bowerman divided this mosaic into plant “communities” based on the varied conditions. The riparian community, growing along streams in places like Sycamore and Curry Canyons, has deciduous trees such as sycamore, bigleaf maple, and cottonwood. Sun-dappled grapevines twine overhead, and shrubs like snowberry cover the ground. Almost as lush, and much shadier, is what Bowerman called the broadleaf-sclerophyll community, which grows in moist places such as the north-facing slopes above Pine, Curry, and Mitchell Canyons. Most of its species, including coast live oak, madrone, and California laurel, have tough evergreen (“sclerophyllous”) leaves adapted to dry summers. The deciduous oak-pine community occurs in rockier, drier areas (such as at Castle Rock and Rock City), and also in parklike savannas where scattered valley oak, blue oak, and black oak—interspersed with gray or Coulter pines—grow amid grasses and wildflowers (the ridgetops along the Burma Road trail or near Mitchell Canyon).

Bowerman’s other two communities occur in places where trees have trouble growing. Grassland gives the mountain its fireworks of poppies and lupines in spring and its golden glow in summer. On Long Ridge, the serpentine soil helps to keep out exotic grasses; Bald Ridge and Donner Canyon are also excellent grassland sites for wildflowers. Chaparral occurs in places too dry, steep, and rocky even for grassland, covering most of the mountain’s south-facing slopes with a shaggy carpet of shrubs that would be desert-like if it weren’t so dense. Chaparral may look monotonous at first glance, but has a wealth of characteristic species. Its shrubs flower throughout much of the year, from manzanita in early winter, through aromatic buckbrush in spring, to chamise in the heat of summer. These flowers, from the white of chamise and buckbrush to the neon magenta of chaparral pea and electric blue of California lilac, can be so profuse that they color entire slopes and perfume the air.

But even that diversity of plant communities doesn’t quite capture the complexity of the mountain’s ecology. The gradations and transition zones between them become their own distinct habitats. As it happened, the elusive Mount Diablo buckwheat appears to depend on one such boundary area, between grassland and chaparral. C.F. Baker, the earlier collector, had noted that the little plant grew in places where the two communities met, and that was indeed where Mary Bowerman found it. She wrote that it grew with chaparral plants such as poison oak and California sagebrush, but also with grassland ones such as brome. That was interesting, because many new species are thought to evolve in places where different habitats meet or conditions otherwise shift.

Eriogonum truncatum might indeed have evolved in the last 500,000 years, as the mountain’s steepening slopes and lengthening rain shadow created new conditions. But it was hard to learn more about the little wildflower, because Bowerman didn’t find any specimens after 1936, and neither did anyone else. As the decades passed, Mount Diablo buckwheat appeared to have gone extinct.

The Price of Progress

Extinction of Mount Diablo buckwheat would not have been surprising in the mid-20th century, given the cascading effects of increased human activity taking place in its preferred habitat on and around the mountain. In the centuries prior to the arrival of the Spaniards, the local Bolbones had burned vegetation to foster game and food plants, but that had probably not threatened annuals like E. truncatum. In fact, it may even have benefited them by reducing competition from the perennial plants that dominated California’s native grasslands. But the advent of European agriculture would have had the opposite effect. Livestock herds introduced by Spanish settlers brought seeds of aggressive weeds such as wild oats; these grew so thickly that they replaced native grasses and forbs over large areas in just a short time. Grazing and weeds increased when Americans homesteaded the mountain; settlers also cut trees for firewood and burned chaparral to enhance grazing. Miners dug up large areas in search of products like lime, coal, and mercury.

Many homesteads failed because of the semiarid climate, but as communities around the mountain grew in the early 1900s, entrepreneurs and officials expected that Mount Diablo’s natural landscape would give way to profitable urbanization sooner or later. It became a popular resort destination after the building of two stagecoach roads to the Mountain House Hotel below the summit in the 1870s. Between 1910 and 1917, an entrepreneur named Robert Noble Burgess acquired some 60 square miles in the area, relined the old stage roads for autos, and extended them to the summit. (These three road sections, which Burgess called the Mount Diablo Scenic Boulevard, were the origin of the park’s present North Gate and South Gate Roads.) Burgess hoped to develop a huge housing estate on his land, and in 1914, William Randolph Hearst, the newspaper magnate, contemplated buying 15,000 acres and placing a castle-like hotel on the summit.

Hearst built his castle at San Simeon instead, and Burgess went bankrupt during World War I, but a business partner in another venture, Walter P. Frick, continued to hold land on and around the mountain. If the boom of the 1920s had continued, he probably would have subdivided much of it for urban uses. However, Frick was sympathetic to the mountain’s natural landscape as well—he liked to camp on it himself—and he gave Mary Bowerman permission to collect on his land. After the Depression threatened his finances and temporarily halted growth, he sold six parcels of his land on the mountain, a total of 2,004 acres, to the state. The first two parcels were dedicated as Mount Diablo State Park in 1931. After Frick’s death in 1937, however, most of the mountain remained in private hands, subject to overgrazing, quarrying, hunting, and other impacts. Increasing pesticide use and poisoning of coyotes and ground squirrels threatened other wildlife such as eagles, burrowing owls, falcons, kit foxes, and badgers.

Pressure for urban growth on the mountain remained comparatively light through the 1940s, but the situation changed after World War II. The Caldecott Tunnel and returning soldiers were soon followed by proliferating freeways, malls, and bedroom communities. Subdivisions started to devour the fields and orchards of the surrounding valleys, and as growth accelerated with the arrival of BART in the 1970s, they spread into the canyons and up to the ridges. One proposed subdivision alone, Blackhawk Ranch below Sycamore Canyon west of the park, planned to pave over some 4,200 acres with luxury homes and commercial development. That was nearly as large as the state park itself, which had grown to 6,788 acres in the 1960s through state bond measures, but which still excluded most of the mountain.

Preserving the Whole

However, other factors began to resist urbanization at this point. As it happened, the last person to collect Mount Diablo buckwheat would play a major part in this resistance. Over the years, Mary Bowerman’s fascination with the mountain’s natural habitats had evolved into a passion to save them from the forces threatening to overrun them. Not content merely to study the vegetation, she foresaw that a small park around the summit would not protect the area’s exceptional ecological values in the long range. “Because there’s so much variation between different parts of the mountain, we need preservation of the whole to understand the whole ecological picture,” she wrote. “It is my dream that the whole of Mount Diablo, including its foothills, will remain open space.”

Bowerman was persistent as well as erudite. She would surprise local landowners, such as the Wright family—proprietors of a private recreation park in Curry Canyon—by asking them what could be done to protect the mountain. “She was talking about us donating [the land] when we were just starting to buy it,” Dorothy Wright recalled. “We thought she was crazy, but she’d talk about nature, the future, the mountain, then five or six years later she’d show up again. I realize now what a neat thing it is to have your priorities in something that will last, into perpetuity.” (Bowerman’s persistence eventually paid off when Wright sold part of her property for inclusion in the park in 2002.)

When Bowerman moved from Berkeley to Lafayette in 1954, she became active in local conservation but found that Mount Diablo often took a back seat to other causes, so she started asking: “What can we do for the mountain?” In 1971, Bowerman’s persistence led Art Bonwell, an engineer who hiked and bicycled in the park, to suggest they start an organization dedicated to protecting the mountain. Bonwell had served as chair of the Mount Diablo Regional Group of the Sierra Club, and knew a lot of conservationists, so, as he says, “I was the organizer and she was the inspiration.” What became Save Mount Diablo (SMD) held its first meeting in December of that year, with 20 participants chipping in 25 cents apiece to get the minutes mailed.

From the beginning, SMD advocated expanding the state park through public acquisitions. Thanks to a combination of tenacious citizen pressure and state park funds, the park grew to over 19,000 acres by the end of the century.

Where public bodies were short of money to buy important areas that became available, SMD often raised the funds to acquire them with the idea of eventually transferring them to public ownership. The organization’s first purchase was 117 acres at the corner of Marsh Creek and Morgan Territory Roads in 1976. The most recent purchase is Mangini Ranch on the park’s northwest side. The 208-acre property, owned by the Mangini family for over 125 years until its sale in 2006, has exceptional habitat for wildlife and plants, featuring the northernmost stand of desert olive, a typical Mojave Desert species, and several endemic wildflowers, including hospital canyon larkspur, a spectacular pink-flowered species that stands up to six feet tall in wet years. Mangini Ranch is also one of the sites where Mary Bowerman found Brewer’s buckwheat, and although the plant has not been found there since, its grassland-chaparral interface habitat remains. A grant from the State Coastal Conservancy facilitated completion of the purchase.

SMD opposed subdivisions that encroached on significant natural habitats, and tried to mitigate urbanization by encouraging owners to dedicate parts of their lands to conservation. An early achievement involved the huge Black-hawk subdivision. In the 1970s, SMD negotiated for 2,052 of the property’s 4,200 acres to be dedicated to the state park as a condition of development, including many of the most scenic areas on the mountain’s southwest flank, such as the Black Hills, the Wall Point area, Blackhawk Ridge, and parts of Dan Cook and Jackass Canyons.

Corridors for Conservation

As urbanization spread, it became obvious to SMD and other conservationists that protecting only Mount Diablo would not be enough to ensure the long-term preservation of its biotic diversity. Studies of “island ecology” throughout the world show that when natural areas become isolated, they steadily lose diversity. Wild populations, under normal stress from predators, disease, weather, and other factors, are always in danger of local extinction. Under natural circumstances, recolonization from adjacent areas replenishes them, but when a park is surrounded by urbanization, plant and animal species may be unable to recolonize it.

And Mount Diablo has lost species in recent times. For example, native rainbow trout lived in Mitchell Creek until the 1980s, but have not been found there recently. Plants also have disappeared, and not just rare ones. Mary Bowerman found leopard lilies on the mountain in the 1930s, but those tall orange flowers have not been seen since, probably a victim of livestock and feral pig damage at the springs where the lilies grew.

Shadows of Mount Diablo
The shadow of development still hangs over some of thefoothills east of the mountain, seen here in this sunset view of theSummit Museum and Devil’s Pulpit. Photo by Charles Benton, Kite Aerial Photography

The studies have also shown, however, that relatively small areas can continue to protect significantly diverse animal and plant populations if they are linked together as “wildlife corridors,” along which migration, recolonization, and other natural processes can continue. The fact that the state park is adjacent to other protected or as yet undeveloped areas is the reason why large charismatic species like mountain lions and bobcats continue to occur in it. The future of diversity in places like Mount Diablo depends on establishing and maintaining such corridors, and SMD’s long-term strategy includes the reintroduction of native species such as rainbow trout and leopard lilies, as is already being done with peregrine falcons (see sidebar).

Accordingly, the primary objective has shifted from expansion of the state park to promoting protection of open space around the mountain. Bob Doyle, president of SMD’s board of directors from 1978 to 1989, recalls that SMD’s drive to link natural areas into wildlife corridors began as urbanization threatened to isolate the park from vital areas that the East Bay Regional Park District (EBRPD) was interested in acquiring—Morgan Territory to the east and Black Diamond Mines to the north. On the west slope, where urbanization pressure was strongest, SMD worked with local communities to acquire and maintain municipal open space around the park at Lime Ridge, Shell Ridge, Crystyl Ranch, and other areas. The Mangini Ranch will be vital in connecting the park with Walnut Creek’s Lime Ridge Open Space.

Linking Mount Diablo’s 19,000-plus acres with the roughly 70,000 acres of other protected open space areas outside the state park between Walnut Creek and Antioch to the north and Livermore to the south has become a top priority for SMD today. These 29 separate units of open space are perceived not as isolated preserves, but as corridors that allow plants and animals to continue to move according to natural patterns. This vision is embodied in the concept of a “Diablo Grand Loop,” a continuous trail through the open space of the northern Diablo Range, from the mountain south to the Los Vaqueros watershed, looping north and east through the new Cowell Ranch State Park and Black Diamond Mines Regional Preserve. (See map on page 24) Only a few gaps remain in this loop, which—if completed—would be both an embodiment of, and a tribute to, Mary Bowerman’s vision of an irreplaceable ecological crossroads protected in perpetuity.

Return of the Native

Mary Bowerman died in August 2005 at the age of 97, but not before her life’s work—like the life of the mountain itself—took another surprising turn. Her book about Mount Diablo’s vegetation had gone out of print, so in the mid-1990s, she began collaborating with Barbara Ertter, a botanist at U.C. Berkeley’s Jepson Herbarium, on an updated and expanded version (published by the California Native Plant Society in 2002). The project involved intensive new exploration of the mountain’s vegetation, and collectors found a number of plants that had not yet been recorded there. But they also failed to find some that had been collected formerly, including Mount Diablo buckwheat.

Exploration continued after the book’s publication, however. In May 2005, Michael Park, a UC Berkeley botany graduate student collecting on land that SMD had previously protected, found a little pink annual wildflower growing between grassland and chaparral. “I was looking at a common plant that likes rock outcroppings and wondering why it was growing on sand when I realized that I was surrounded by early blooming buckwheat,” Park recalls. “I decided I needed a closer look since I didn’t recognize it and then realized this was something new. Once I realized it was Mount Diablo buckwheat I was in shock . . . It’s a surprisingly dainty plant once you see it in the field, because it’s so celebrated in the botanical community that it had grown in my imagination. It’s only because I stopped and was moving very slowly that I even realized it was there.” Ertter agreed with Park’s identification, and other botanists confirmed it.

As it happened, news of a possible sighting of an ivory-billed woodpecker—also believed extinct for decades—in an Arkansas swamp had emerged three weeks earlier, so the media were primed to take notice of this latest return from apparent extinction. National Public Radio interviewed Barbara Ertter and Seth Adams, SMD’s Director of Land Programs. “With all the normal controversies and land battles,” Adams said, “what great news that this beautiful and unique wildflower has managed to survive. When I visited the site I was struck by how fragile the plant is. There are fewer than 20, it’s an annual and reseeds and dies each year, but has managed to survive.”

The species’s future is far from certain, in part because botanists aren’t sure how it has managed to survive. One theory involves rabbits, which hide from predators in chaparral’s dense brush and venture into adjacent open grassland to feed. By thinning exotic weeds at the chaparral’s edge, the rabbits may be helping out the rare natives. But science still knows little about protecting endangered species like the buckwheat. Although propagating them in nursery can preserve their genetic material—botanists at UC Berkeley Botanical Garden have just announced the successful flowering of plants grown from seeds collected in 2005—they can’t really survive unless viable populations continue to reproduce in their natural habitat. The plant’s reappearance on the mountain in the spring of 2006 is certainly good news, but not a guarantee.

So it keeps coming back to the need to preserve habitat. “Our first priority,” says SMD Executive Director Ron Brown, “is to make sure Mount Diablo is not cut off from the rest of the Diablo Range to the south, so that the area retains healthy breeding populations and an enriched gene pool of plants and animals. Second, although SMD has done a good job of defining the outer edges of the habitat we want to protect, we need to fill in those limits with large enough swaths of protected land to sustain wildlife and provide visual and recreational amenities.”

Brown says SMD has benefited from good relations with landowners, many of whom share its values and goals. “We believe that our ancestors would be very proud of us for working with Save Mount Diablo,” says Karen Mangini, one of the former owners of Mangini Ranch. “It is our responsibility to protect this land for others. We want future generations to enjoy what we had; we want them to be able to roam among the land’s friendly confines as we have done—We hope that the work we are doing with Save Mount Diablo will encourage other farming and ranching families in this beautiful valley to do likewise.”

SMD estimates that the amount of protected land in this area will have to double before its work is finished. Considering the obstacles besetting conservation, this might seem a long shot. California didn’t pass a major park bond issue between Proposition 70 in 1988 and Propositions 12 and 40 in 2000 and 2002. These funds have quickly been spent; local land prices are jumping dramatically; and new state bond funds, due to be voted on in November 2006, will be sorely needed. “Urban pressure for large scale developments in the foothills has never been greater,” says former board president Bob Doyle, now assistant general manager for land acquisition at the East Bay Regional Park District.

But Mount Diablo still specializes in surprises, as I found when I recently visited Round Valley, a relatively new regional preserve adjacent to Morgan Territory southeast of the mountain, and very near where Brewer first found Eriogonum truncatum. Since it is in the peak’s rain shadow and has desert species like kit foxes and roadrunners, I anticipated a somewhat forbidding place. But it was a very wet April, and Round Valley was like yet another sequence from Disney’s Fantasia, the “Pastorale Symphony.” Meadowlarks sang in emerald turf spangled with buttercups; flocks of bluebirds, goldfinches, and warblers thronged oaks almost as stately as those Brewer described in 1862.

I didn’t see Mount Diablo buckwheat, but I did see something that surprised me, a big dark green and pink woodpecker—most certainly a Lewis’s woodpecker. This is the West’s most unusually colored woodpecker. Captain Meriwether Lewis, who discovered it for science in 1805, aptly described its breast plumage as “a curious mixture of white and blood red which has the appearance of having been artificially painted or stained that color.” The species also behaves in un-wooderpeckerlike ways, flying straight ahead like a crow (most woodpeckers have an arcing flight) and hawking insects from a perch. Like Mount Diablo buckwheat, Lewis’s woodpecker has specialized habitat needs and is threatened by exotic species and human activities. Starlings appropriate its nest holes in large, scattered trees, and people cut the trees. I don’t recall seeing the species anywhere else in the Bay Area in over three decades of hiking here. If Round Valley had become a landfill as was proposed in the 1980s, I might never have seen it here.

Lewis’s woodpecker lives from central British Columbia to northern Mexico, and east to the Great Plains, but it is uncommon and local enough throughout its range that seeing one is always a thrill. Such sightings are good indicators of the biodiversity that Save Mount Diablo and its allies are trying to protect. The more linked habitat there is in an area, the more chance there is that an unusual species like a Lewis’s woodpecker or a San Joaquin kit fox—or even a Mount Diablo buckwheat—will still be there to surprise and delight us for a long time to come.

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one comment:

Michael Marchiano on September 29th, 2013 at 12:52 pm

A very well researched and written article about Mt. Diablo. It is truly made up of multiple ecosystems and micro-habitats that offer special treasures every season of the year.

A little side note…the Lewis’s woodpecker can be seen seasonally at Los Vaqueros Reservoir and in the Morgan Territory Regional Park in Contra Costa County (as you know both border Round Valley) and on a regular basis and in East Alameda County, especially Del Valle Reservoir.

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