Climbing high to save a threatened West Coast plant

Protruding from a cliff face, a diminutive desert plant peered across a sapphire channel as flames charred the earth hundreds of feet below. The remote pinnacle should have protected the onlooker, as it had in the past, but the blaze was too hot. This time, the mountain burned, and the tiny succulent, known as Verity’s liveforever, wilted and died.

As the May 2013 Camarillo Springs fire cooked 98 square kilometers of coastal valley just northwest of Los Angeles, it almost wiped out the Verity’s liveforever, a dudleya succulent once abundant among the western Santa Monica Mountains.

This wasn’t the first time human actions caused problems for a dudleya (pronounced like the name Dudley with an “uh” on the end). Of the 45 or so dudleya species spread across the western United States and Mexico, nearly a quarter are threatened or endangered. The destruction has assumed many forms, from classic threats such as suburban development to imported colonies of hungry bunnies.

As their name suggests, however, liveforevers are survivors, subsisting for decades where most other plants can’t. With pointy yellow flowers and low, thick leaves arranged like a star, Verity’s liveforever (Dudleya verityi) inhabits rocky, nutrient-poor outcrops. The munchkin liveforever (Dudleya gnoma), boasting stubby, pinkish leaves, survives on a gusty mesa on the Channel Islands offshore of Southern California, where 40 mile per hour winds are too much for most plants to take root.

Good thing liveforevers are tough. They provide sustenance for a bevy of pollinators, from bees to wasps to hummingbirds. The jewel beetle Chrysobothris dudleyaphaga, as its name suggests, survives on dudleya. As with other rare and endangered plant species, dudleya’s loss would be felt. 

“Remove enough bricks and the whole house collapses,” says Mark Elvin, a U.S. Fish and Wildlife biologist based in Ventura, Calif. Elvin and his team of botanists keep tabs on plants located in the Santa Monica Mountains that are protected by the Endangered Species Act. Several dudleyas are under their watch.

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“All of the ESA-listed species help maintain ecological balance in the world, and consequently, productivity for humans,” Elvin says.

Dudleyas are one beacon exposing how human behaviors, even seemingly inconsequential ones, can erode nature. The Camarillo Springs fire is a marquee illustration. After an undetermined spark, perhaps a discarded cigarette, ignited the blaze along California Highway 101, a contaminant in the soil, a by-product of a successful state campaign to improve air quality, likely encouraged grass overgrowth that fed the fire.

This extra punch urged the nine-day inferno toward the Verity’s liveforever’s secluded habitat on Conejo Mountain (in the Santa Monica range), suspects Stephen McCabe, a botanist at the University of California, Santa Cruz. In 2009, the liveforever population on Conejo numbered 3,450. “In less than two weeks, the fire wiped out 93 percent of what was already a rare species.” Fewer than 300 remain today, according to McCabe and Elvin.

The situation calls for a daring rescue, and this fall, Elvin, McCabe and a group of botanists are planning such a feat. They will creep along vertigo-inducing ledges to rebuild the dudleyas’ cliffside homes. With an invaluable stockpile of seeds squirreled away inside McCabe’s greenhouse, the climbers hope to ensure that the Verity’s liveforever survives a bit longer.

Back from the brink, again

Dudleyas don’t actually live forever, though killing them takes effort. The plants earned their nickname in the 1800s after naturalists transported some home from California to Europe. “They would smash the dudleyas inside plant presses, take the long boat ride back to England, open up the plant press, and the dudleyas were still alive,” McCabe says.

Their resilience stems from an ability to store and conserve water in their plump succulent leaves for extensive periods of time. The skill comes in handy in their mostly arid habitats. Though a few inhabit Nevada and Arizona, most liveforevers pepper sea-hugging hills and coastal mountains from southern Oregon through California and down into Mexico. The plant’s range is predominantly characterized by a Mediterranean climate, where rain sporadically falls during the winter, while the rest of the year is dry with occasional fog.

The succulents also sprout on the island chains along the West Coast, which is where they first encountered major trouble with humans. The San Benito Islands, an archipelago off Mexico’s Baja California, are uninhabited, except for some fishermen who camp overnight and a sole lighthouse keeper on the westernmost isle. Yet this modest intrusion was enough to endanger native plants.

European rabbits arrived on West Benito Island in 1991, perhaps brought as hunting game by the lighthouse keeper or the fishermen. The critters gorged on the native flora, including the resident liveforever (Dudleya linearis).

“The rabbits skewed the whole plant community,” says ecologist Josh Donlan, who studied the region in the late 1990s while working for Island Conservation, an ecological agency that aims to prevent extinctions of island life. Donlan and his colleagues found that the rabbits voraciously consumed certain species, such as D. linearis, while leaving others untouched.

So in 1998, Donlan and Island Conservation decided to rid the islands of nonnative herbivores.

“They hired a trained Jack Russell terrier named Freckles that rooted out rabbit burrows,” says Steven Junak, a botanist with the Santa Barbara Botanic Garden. “The dog single-handedly eliminated the rabbits from West San Benito Island.”

With the 400 or so rabbits gone, the dudleyas rebounded, which Donlan attributes to leftover seeds in the soil and the arrival of El Niño rains.

The success reminded Junak, an expert on the flora of Californian and Mexican islands, of a close call on another coastal island, this time due to Belgian hares introduced by farmers in 1942. By 1970, the Santa Barbara Island liveforever (Dudleya traskiae) had been decimated; experts deemed them extinct in the wild. Once the animals were removed in 1981, however, the liveforevers bounced back. The herbivores had left gnawed stubs of the hardy plants in the ground, giving rise to a new generation of the succulents. A tenuous population of about 1,000 Santa Barbara Island liveforevers inhabits the island today.

Lifesaving lichens

An identical happy ending for the Verity’s liveforever of Southern California seems unlikely. 

“Many of the plants were outright destroyed by the fire,” says John Tiszler, a plant ecologist with the U.S. National Park Service and a partner in the restoration project. Tiszler and company noted a fair number of seedlings last winter, but all subsequently died as California entered its third year of a crippling drought, making a natural revival unlikely.

Facing such devastation, McCabe, Elvin, Tiszler and colleagues aim to rebuild the plants’ habitat from scratch.

Many regard Stephen McCabe as the premier expert on dudleya taxonomy and cultivation, with his greenhouse at the UC Santa Cruz arboretum harboring almost every known species.

“People say if you give Stephen a pencil and he plants it, he can get it to grow,” remarks Elvin.

McCabe will cultivate Verity’s liveforevers in his outdoor laboratory, a kind of island of Doctor Moreau for plants. Strange genetic hybrids cover every table. Some hybrids spill open like peeled artichokes with tentacle-like stems shooting out the sides. Others are blood red with bulbous leaves shaped like snap peas. Each was spawned over years, sometimes decades, by classic breeding techniques.

To retain the integrity of the species, however, only true Verity’s liveforevers will be reintroduced at Camarillo. Tiszler has tracked down geneticists at UCLA and UC Berkeley who will confirm which specimens represent pure breeds.

McCabe’s nursery also contains specimens of the Verity’s succulent that were collected from the cliffs before the fire. Given that this dudleya species is threatened with extinction, a few plants will be transferred to backup locations at Tiszler’s laboratory in Thousand Oaks, Calif., and at another location at the Channel Islands National Park. If anything happens at one location, Elvin says, “we don’t want to lose all the replacement strains.”

The succulent’s cliff-hanging lifestyle won’t make the project any easier. “The big question is how to establish nursery beds under these extreme conditions,” Tiszler says. The Verity’s liveforever can sprout from rock walls, but like any plant, they require a soil bed, moisture and adequate sunshine.

Two lichens — Niebla ceruchoides and Niebla homalea — could be the key. Both resemble tumbleweeds cemented to boulders, though they are actually a partnership between microscopic algae and fungus clinging to the rock. Verity’s liveforevers primarily grow alongside and on top of the Niebla lichens. Bits of falling dirt and clay lodge behind the lichens’ perch, creating a serene microhabitat for sprouting liveforevers, says Kerry Knudsen, who is curator of lichens at the UC Riverside herbarium.

As Pacific fog rolls over the coastal mountains, dew collects on the lichens’ blades. Water trickles into the nuggets of soil, where dudleya seeds take root. “The lichens appear to be essential for the reproductive success of Dudleya verityi,” says Elvin.

The lichens at Camarillo were well established, but like the dudleyas, they perished in the fire, says Knudsen, who surveyed the area before the fire. “Based upon the size of the lichens there, that area hadn’t burned in maybe a hundred years,” he says. No previous fire had been as intense as the Camarillo Springs fire, the fifth largest in the Santa Monica Mountains’ recorded history, which dates back to the early 1900s.

From the frying pan 

The ongoing drought undoubtedly contributed to the inferno’s fury. But a soil contaminant described in a 2010 paper in the Journal of Environmental Management by Mark Fenn and colleagues at the U.S. Forest Service, also inadvertently may have stoked the furnace.

For almost half a century, the United States has tried curbing harmful NO_x — nitrogen oxides — from its air. And California has led the way. After 1975, all new cars had to have catalytic converters for their exhaust, which convert NO_x into other nitrogen-based gases. The state’s strict emissions standards for cars and trucks cut local NO_x pollution by 40 percent between 1990 and 2010.

An overlooked by-product of the catalytic converters is ammonia, which is not regulated, says conservation biologist Stuart Weiss of the Creekside Center for Earth Observation in Menlo Park, Calif. Recent estimates suggest that ammonia now constitutes 20 to 30 percent of nitrogen-based vehicle emissions in California.

Ammonia deposition occurs mainly near high-traffic roadways. Nonnative, or invasive, grasses gobble up the extra ammonia as it settles. (Ammonia, a major component of fertilizer, is rich in nitrogen, which all plants need to grow.) As the contaminant takes root, the long grasses prosper, blotting out the sun for smaller wildflowers. The invasive plants require year-round hydration, and when groundwater runs dry in the summer, the plants become kindling. The grasses tend to sprout on formerly barren or low-growing land, which helps wildfires spread in sparse scrub or desert environments.

“It just builds up a fine fuel load, and you get a more intense fire,” Weiss says. This scenario probably influenced the Camarillo blaze, he says. Invasive grass growth was robust near the freeway where the fire began.

Two-step rebirth

With the mountainside scorched and desolate, the reintroduction of the Verity’s liveforever must start from scratch. Step one of the proposed plan involves moving N. ceruchoides and N. homalea lichens from the Channel Islands off Santa Barbara to the liveforever’s charred habitat on the mainland.

“Lichens damaged in the fire continue to fall off the cliff,” McCabe says. Even with intervention, he estimates it will take 80 to 100 years before the Verity’s liveforever will reach its pre-fire numbers. 

The burned zone was the only mainland location for N. ceruchoides for about 112 kilometers, according to Knudsen. But lichens flourish on the nearby Channel Islands. “On the islands, N. homalea numbers in the millions. The other species is less common, but still fairly abundant,” Knudsen says.

The plan could work because of the lichens’ unusual biology. Niebla lichens lack roots and do not sap nutrients from the ground. Instead, they sport a stemlike thallus with tiny grappling hooks on the bottom called rhizines. Algae pack the thallus, which draws moisture from the air to supply these tiny tenants. The algae, in turn, feed the lichens’ fungal cells. Rhizines adhere the lichens to rocks, but freeing the attachments shouldn’t harm the lichens, Knudsen says.

Before winter, the group proposes to transfer 400 lichens to the Santa Monica Mountains, gluing them by their bases to rock walls. Over the next two years, the researchers would monitor the lichens’ survival.

Once the lichens settle, the group will climb high and broadcast Verity’s liveforever seeds across the rock wall, hoping that a few will catch in the lichen roosts. In some spots, adult liveforevers might be placed in special pots overhanging the ledge, so that their seeds will naturally fall into the cliff-hanging lichen beds. “Those seeds that tend to stick and germinate should be genetically predisposed to surviving in that habitat,” Elvin notes.

The continuing drought is going to make this hard, Knudsen says. Last winter, California had the lowest rainfall in recorded history and the state’s signature fog has rolled in less frequently than in the past. Fog helps maintain the lichens and the dudleyas, in particular as the liveforevers grow from the tiny seedling stage to flowering size, McCabe says.

New human-made threats are sprouting too. A quarry has purchased much of the land on Conejo Mountain where a large patch of Verity’s liveforevers  formerly grew.

But the resurrection marches on. “Right now we want to ensure that the Verity’s doesn’t go extinct. We’re spending our resources mostly on keeping it alive,” says Elvin with a whisper of exhaustion. “Humans are responsible for this species’ current status. It is our responsibility to keep it from falling over the precipice.”

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This article appears in the October 18, 2014, issue of Science News with the title, “Resurrecting lifeforevers: Saving a native plant from extinction after a devastating fire.”