Bay Nature magazineFall 2007


Presumed Extinct

October 1, 2007

When botanist Michael Park stumbled across a stand of spindly little plants on Mount Diablo in May 2005, he was momentarily taken aback by the pale pink flowers. He continued with his scheduled plant survey before returning several hours later to key out what was eventually confirmed as Mount Diablo buckwheat—heralding the reappearance of a plant long thought extinct. The buckwheat, originally collected by botanist William H. Brewer in 1862, was last seen in 1936 by UC Berkeley botany graduate student (and later Save Mount Diablo cofounder) Mary Bowerman. Although most of the world had given up on finding this dodo bird of the plant kingdom, Park and others kept the buckwheat’s image in mind, just in case.

As with the presumed extinct ivory-billed woodpecker reported in Arkansas not long before Park found the buckwheat, there is always the chance that a long-lost plant or animal will be rediscovered, thanks to persistent searching, luck, and, of course, a bit of remaining suitable habitat. That’s true even in a busy metropolitan area with nearly seven million people—as evidenced by Park’s historic find at the edge of suburbia.

Also in May 2005, botanists Brad D. Schafer and Margaret Widdowson found another plant previously presumed extinct, on Solano County’s suburban edge. Bearded popcorn flower was known to have been collected only twice: in 1883 in Elmira (north of the Jepson Prairie), and in 1892 in the Montezuma Hills. The May 2005 discovery came after 15 years of searching by Schafer and botanist Robert E. Preston, who together confirmed four additional populations in vernal pool grasslands at the Wilcox Ranch and Jepson Prairie preserves in Solano County as well as on nearby private lands.

But for every such long-lost species found, several have followed in the footsteps of the dodo. The Xerces blue butterfly was endemic to the San Francisco Peninsula. Only 23 years after its description in 1852, lepidopterist Herman Behr noted its incipient extinction as the city overtook the sand dunes. At the Presidio’s Lobos Creek in 1941, future UC Davis entomology professor W. Harry Lange unknowingly netted what would turn out to be the last recorded Xerces and popped it in a killing jar. Revisiting the Presidio a few years before his death, Lange lamented: “I always thought there would be more. I was wrong.”

Two more local butterflies followed the Xerces into oblivion. The Sthenele satyr and Pheres blue were collected by Forty Niner-turned-entomologist Pierre Joseph Michel Lorquin around 1850 in the city’s westerly dunes. By 1880, the Sthenele satyr had disappeared. About the Pheres blue we know only that it was reported at 14th Avenue and Taraval Street, and on the dunes west of 20th Avenue. The first population was extirpated around 1926, the second by 1940. By 1950, the Pheres blue had vanished.

All these species were adapted to a particular niche in the Bay Area’s diverse environment, but apparently they were not so well adapted to coexisting with us. Spurred by the rediscovery of the buckwheat and popcorn flower, we at Bay Nature wondered if there were any other species that might be recovered from the list of the lost. Here we take a look at several plants and animals that scientists continue to search for—in the hope they may still be hanging on by a thread, waiting to be found and protected.

On a Wing and a Prayer

In the wake of San Francisco’s doomed dune butterflies—the Xerces, Pheres, and Sthenele—two additional butterflies may have fluttered their last flight within living memory. In the Santa Cruz Mountains, Strohbeen’s Parnassian butterfly (Parnassius clodius strohbeeni) glided through the redwoods, frequenting well-lit canyon bottoms and stream zones, unique in itself since other species of Parnassian inhabit higher elevations. Strohbeen’s Parnassian was first collected in 1923 by John Strohbeen during a fishing trip in the Santa Cruz Mountains at a site later destroyed by road construction. The butterfly’s larval host plant, western bleeding heart (Dicentra formosa), later waned in numbers due to over-collection for the nursery trade. In 1956, entomologist James Wilson Tilden observed the last known living members of this species—a small colony in the vicinity of Bonny Doon atop Mount Ben Lomond.

A more likely candidate for survival is the federally endangered lotis blue butterfly (Lycaeides idas lotis). The lotis blue was described in 1879 by entomologist Joseph Albert Lintner based on a specimen labeled “Mendocino” from the collection of renowned lepidopterist William Henry Edwards. Who wielded the net remains a mystery, one that vexed even novelist and amateur lepidopterist Vladimir Nabokov when he revised the taxonomy of North American blues in the 1940s. The lotis blue frequented Mendocino and Sonoma counties’ wet meadows and sphagnum-willow bogs. It’s not known what drove the species toward extinction, but urban development, fire suppression, drought, and groundwater drawdown are all likely suspects. Today, suitable habitat for the species is restricted to a single bog on PG&E land in Mendocino’s Pygmy Forest south of Fort Bragg. The lotis blue was last seen there in 1983, and its suspected host plant, seaside bird’s-foot trefoil (Lotus formosis-simus)—though otherwise common—hasn’t been seen there since 2000.

Over the years, entomologist Richard Arnold has kept an eye out for sun-dappled forest clearings or boggy spots that might harbor long-lost butterflies. “You always hope that maybe there’s some place you haven’t been yet,” he says. “The problem is, you run into small stands of food plant, but not the large stands needed to sustain a population.” With so many people tuned in to butterflies, “it’s unlikely a butterfly could go unnoticed for years on end,” says retired UC Berkeley entomologist Jerry Powell. But it happens. In 1990, Arnold was part of a team that happened on the only known population of federally endangered Behren’s silverspot butterfly near Point Arena, a species that hadn’t been seen in many years.

Fish Out of Water

With major fisheries teetering on the brink of collapse, it’s unlikely that many people have noticed the plight of two Bay Area endemic minnows that haven’t touched a creel in 30 years or more. The Clear Lake splittail (Pogonichthys ciscoides), the lake-bound cousin of the Sacramento splittail, is said to have schooled in great numbers in Clear Lake, the largest natural lake in California. In April and May, the eight-inch-long splittail would venture into upstream tributaries to spawn. Three weeks later, the young would return to the lake to feed on zooplankton and the native Clear Lake gnat in silvery schools that led early settlers to call them “silversides.” In the early 1940s, Clear Lake splittail populations plummeted, but it wasn’t until 1973 that the fish was belatedly recognized as a species. At about that time splittail vanished from the lake, replaced by non-native bluegill and, ironically, the inland silverside (P. macrolepidotus). The latter was introduced in 1967 by the state to control vast clouds of annoying but harmless Clear Lake gnats, and it likely outcompeted Clear Lake splittail for shallow shoreline habitat. Other factors that may have tipped the species toward extinction were the channelization and the diversion of Clear Lake’s tributaries, where the splittail spawned.

Thicktail Chub
Last seen in 1957, the thicktail chub (Gila crassicauda), above, was once widespread in Central California. Clear Lake splittail (Pogonichthys ciscoides), foreground, schooled in great numbers in its namesake lake until it was displaced by introduced competitors. Illustration by Devin Cecil-Wishing.

Although its bones dominate Native American middens along the Sacramento River, Putah Creek, and the Pajaro-Salinas drainage, the thicktail chub (Gila crassicauda) is even less well known. This four-inch-long chub was also found in Clear Lake, the Delta, the Napa River, Alameda Creek, and several other Bay tributaries. Up until the late 19th century, thicktail chub weren’t uncommon in San Francisco fish markets, and their remains have been recovered from 19th-century Chinese privies in the city’s Mission District. But as early as 1884 their populations were reportedly waning. In 1957, the last known specimen was caught in the Sacramento River near Rio Vista. Throughout the species’ range, stream diversions and modifications, the loss of tule beds and shallow lowland lakes, and the introduction of largemouth bass and other nonnative predators likely drove the thicktail chub to extinction.

Since both the San Francisco estuary and Clear Lake are regularly sampled, UC Davis fisheries biologist Peter Moyle says the likelihood of finding either species is close to zero. But Robert Leidy, an ecologist with the U.S. Environmental Protection Agency, remains optimistic about the thicktail chub. “It could possibly show up in any part of its historical habitat,” says Leidy. “It could be upper Coyote Creek, it could be the Pajaro drainage, it could be in North Bay marshes or the Petaluma River.”

By Serendipity

On one weekend every June, deep in the heart of the Sacramento-San Joaquin Delta, the town of Isleton comes alive to celebrate its annual Crawdad Festival. Curiously enough, amid the crawdad sausages and jambalayas, the only thing missing is the native crawdad that once inhabited local streams: the sooty crayfish (Pacifastacus nigrescens). Only two other crayfish are native to California’s waters: the Shasta crayfish (P. fortis), a state and federally endangered species found only in Shasta County, and the Klamath signal crayfish (P. leniusculus klamathensis) of far Northern California. From the original 1857 description by marine biologist William Stimpson, we know only that the sooty crayfish was four inches long, blackish, and “common in the vicinity of San Francisco.” It otherwise closely resembled the Shasta crayfish. In the late 1800s the species was reportedly common in Central California streams, including Alameda and Coyote creeks, turning up on occasion in San Francisco markets.

Since the sooty crayfish has vanished without a trace, we can only guess that invasive crayfish introduced for bait and food out-competed their sooty cousins. But that hasn’t stopped ecologist Robert Leidy from looking along the upper reaches of Coyote and Alameda creeks, much of which is pristine land with a native wildlife assemblage. “People rediscover species with periodic regularity in places that are fairly well studied,” says Leidy, “As a field biologist, there’s always that sexy idea of finding something long thought extinct.”

The Bay’s miniature San Francisco horseshoe shrimp (Lightiella serendipita)—one of just five Lightiella species known worldwide—is a cephalocarid, among the most primitive of crustaceans, harkening back 500 million years to the Cambrian period. In 1961, Meredith L. Jones, from New York’s American Museum of Natural History, dredged four of these tiny, eyeless shrimp from the muddy sand bottom of the Bay off Point Richmond, making it the only known benthic (bottom dwelling), non-fish species endemic to the Bay. Five more were found in 1987 and 1988 off Brooks Island and Coyote Point, but none have been seen since, despite a California Academy of Sciences “bio-blitz” in search of bottom-dwelling Bay creatures in 2000. Academy curator Rich Mooi says mud samples were taken throughout the Bay where Lightiella had been reported. “I would have expected that if they were there, we would have seen them,” says Mooi. But, he adds, “[the shrimp] are tiny, they’re hard to see, and people hate going through mud.” Then Mooi hints that Lightiella just might be lurking, overlooked, in one of the academy’s many jars of Bay mud, awaiting another sifting. Any takers?

Address Unknown

The little that’s known about the Palo Alto lost thistle (Cirsium praeteriens) would fit on a postage stamp. This elusive white-flowered thistle was collected by lawyer and botanist Joseph Whipple Congdon in 1897 and 1901 at a location identified simply as “Palo Alto,” roughly mapped at the present-day site of the Palo Alto post office. “It seems remarkable,” wrote Harvard botanist James Francis Macbride, “that this splendid thistle should have escaped notice so long since it grows at the very door . . . of one of the principal herbaria [Stanford’s Dudley Herbarium] of the Pacific coast.” Since we know nothing about the thistle’s habitat, botanists like California Polytechnic’s David Keil, the de facto expert on the species, don’t know where to begin looking. “I would guess that it would be a wetland species, since a number of the other native thistles occur with their feet wet,” he explains, “[but] I won’t go looking for it because I don’t know where to start. Going into an urban area to find a plant is a real challenge.”

The story of the Pitkin Marsh Indian paintbrush (Castilleja uliginosa) is one fraught with tragedy. It was first collected in 1937 by botanist John Thomas Howell from two freshwater marshes near Sebastopol. At Trembley’s Marsh, the paintbrush plants were reportedly common between 1937 and 1950, but vanished altogether the following year. They persisted longer at Pitkin’s Marsh, but by 1971, only a single plant remained. The marsh was fenced off in 1978, and in 1984 the paintbrush’s rhododendron host plant—paintbrushes live in part by parasitizing other plants—was trimmed to reduce shading on the single remaining paintbrush stem. Four weak stems survived but were soon overtaken by rushes and sedges. These too were trimmed, but February rains in 1986 flooded the marsh, wiping the palette clean of all traces of the Pitkin Marsh Indian paintbrush in the wild (some plants still grow at the University of California Botanical Garden at Berkeley).

20 k-rats

It was a neighborhood cat, not a biologist, that first collected a Berkeley kangaroo rat (Dipodomys heermanni berkeleyensis) in 1918 atop Dwight Way Hill in Berkeley, or so the story goes. The specimen found its way to Joseph Grinnell, director of the Museum of Vertebrate Zoology in Berkeley, who later described the subspecies based on this and other k-rats from the Berkeley hills. K-rats were later reported in isolated pockets throughout the East Bay hills; the last confirmed one was collected at the Calaveras Reservoir in 1940. All told, 20 individual Berkeley k-rats have been collected and confirmed. But there’s only so much that can be gleaned from museum specimens. About its preferred habitat, we know only what was scribbled in the field notes of the original collectors: bare ridgtops, rocky outcrops, thin soils, scattered chaparral, and small annual grasses. Although too little is known about the Berkeley k-rat to point fingers, there’s a consensus among biologists that urban development and domestic house cats likely took the hop out of the rats’ step.

Since the early 1980s, biologist Gary Beeman has been hot on the k-rat’s tail, plastering “WANTED” posters throughout Mount Diablo State Park seeking reports of the kangaroo rat’s existence, dead or alive. Over the years, reports of alleged k-rat sightings have trickled in, including several trapped and released in the late 1970s, one caught at the base of Mount Diablo and kept as a pet in the 1980s, and one “moused” by a Blackhawk house cat in the 1990s. As with any Bigfoot sighting, there were neither photos nor bodies to back these claims.

Since 2000, East Bay Regional Park District biologist Joe DiDonato has trapped eight k-rats during surveys near Ohlone Regional Wilderness. These Ohlone k-rats bear markings of both the Berkeley k-rat and its closest kin, the Tulare kangaroo rat (D. h. tularensis), and DiDonato is still looking for someone to perform the DNA analysis necessary to identify them definitively. “Until you get genetic data to disprove [berkeleyensis], you have to go on the current science, and the current science is the historic data Grinnell collected.” And based on Grinnell’s range maps, the small, isolated fringe colonies DiDonato has discovered are berkeleyensis.

Despite DiDonato’s discoveries, Beeman continues to search for indisputable proof of the Berkeley k-rat in the core of its original range, where its status as berkeleyensis can’t be questioned. With so many unconfirmed sightings well within the species’ range, Beeman is confident the species will turn up. Where? Alhambra Ridge, Blackhawk Ridge, Lime Ridge, Mount Diablo’s lower slopes, the hills above Crockett, and North Canyon Road in San Ramon are at the top of his list of likely locales.

Meanwhile, other scientists keep searching, in the hopes of finding the next “Lazarus species.” In late July we received news from butterfly expert Arthur Shapiro that after five years of searching in Suisun Marsh, he had rediscovered a race of field crescent butterflies that had been presumed extinct. Where intact habitat remains, so too does the possibility of finding—and protecting—lost species.

About the Author

Matthew Bettelheim is a freelance writer and a wildlife biologist with URS Corporation.