Manatees, panthers and ... ziziphus?
Though prickly and far from cute, the rare Florida plant has its admirers, who are working to keep it from disappearing forever.
By SUSAN ASCHOFF
Published February 12, 2005
LAKE WALES - Ruts in the red clay jostle the RAV4 as Carl Weekley steers between a grove of citrus trees and a wire fence until he reaches a gate looped with a rusty chain. He climbs out, unlocks the gate, then guides the car down a steep ravine, sneaking underneath a massive tree limb.
The limb appears dangerously low for the pickup behind Weekley to clear. Driven by research assistant Jeremy Ash, the truck inches through.
They travel the rest of the way on foot. The pocked ground covered in slippery leaves hungers for an ankle to twist. The pair zigzags single-file down the wooded hill, emerging from the shady darkness into a clearing in the sun.
Here their treasure hides. Two dozen plants of a species so rare it is found only in Florida, so obscure it wasn't named until the 1980s.
Ziziphus celata.
Hidden ziziphus.
The name sizzles on the teeth.
The reality is pathetic. Its woody stems are covered with thorns, its leaves too small to grace its twisted limbs. Perhaps 5-million years old, ziziphus is dying. It produces hundreds of tiny flowers - four can fit on the face of a dime - but the resultant seeds do not sprout.
Ziziphus resists even the dedicated ministrations of these plant ecologists, who deliver pollen with tweezers and keep the secret of its location so gawkers will not trample its sandy hill.
This is an endangered species without star power. The Florida panther pulls in $2.5-million a year from sales of its specialty license plate. Ziziphus has no vanity tag. Its benefactors celebrate a $40,000 federal grant.
Ziziphus is a child only an earth mother could love.
But for Weekley and Ash, for plant geneticists, conservation groups and volunteers, for ranchers who might have been tempted to rip it out but instead protectively fence it in, homely ziziphus is a part of our past worth saving.
Humble treasureFor a decade they've labored to save ziziphus.
They've extracted enzymes from its leaves to look at its genes. They've performed hundreds of hand-pollinations, waiting for the right plant to bloom so its DNA could be mingled with another. They've sown seeds. They've taken cuttings from the wild, coddled them in a nursery, then planted them where they got them. They've set it on fire, to mimic nature's lightning strikes.
All to make ziziphus multiply.
Found only at six known sites in the United States, all in Polk and Highlands counties, Ziziphus is discovered by chance, in pastures and land preserves, stubbornly resisting the incursions of the present day.
The plants in the clearing visited by Weekley grow near Historic Bok Sanctuary, adjacent to a housing subdivision's dump for yard clippings. A Bok curator, scouting for archaeological significance to fend off a planned highway bypass, smelled an overpowering perfume, similar to the scent of orange blossoms, and found ziziphus.
Another cluster of plants was identified about eight years ago on a cattle ranch. Landowner Kathy Friedlander didn't know anything about ziziphus when, on a school field trip with her children to Bok's endangered plant nursery, she was introduced. It looked like a lone clump of bushes growing on their 640 acres, she thought, leaving her phone number for someone to follow up.
When no one did, she dug up one of the plants, dumped it in a pot and brought it back.
"I notice things. I'm curious," Friedlander says. "Our bulls would walk through them to scratch."
Now there's barbed wire fencing around her 30 specimens and ecologists visit regularly to pollinate, count, burn.
"I have to admire the plant," Friedlander says, "for its pure determination to grow."
Losing links in the chainMore than 15,000 species around the world are at risk of extinction, according to the International Union for Conservation of Nature and Natural Resources, or IUCN. Its accounting of threatened plants and animals is known as the "Red List." Humans are largely to blame for its length: People bring pollution and disease and devour habitat. A November report concludes that the current rate of extinctions is 100 to 1,000 times the rate that would occur naturally.
Ziziphus has been listed as endangered - immediately at risk of extinction - in the United States for 16 years. Its nearest relative lives in Baja California.
A sample of the plant was first collected in 1948 near Sebring, but went unnoticed in a drawer for 36 years. Botanists Walter Judd and David Hall finally named the oddity in 1984. They thought it was extinct. Then in 1987, a small population was discovered near a state forest.
Ziziphus, Weekley says, is the "poster child for obscurity."
A plant ecologist, Weekley first studied ziziphus while employed by the Florida Division of Forestry 10 years ago to monitor 15 endangered plant species. Now he is a research assistant in the plant ecology lab at Archbold Biological Station in Lake Placid.
Archbold tracks some 40 species of endangered or rare plants and animals, from the nodding pinweed to the Florida mouse, on 8,000 acres of Florida scrubland and pine woods on the Lake Wales Ridge.
The ridge is called "Florida's attic," stretching 200 miles north to south through the state's center, a cache of species found nowhere else on Earth.
Ziziphus is the ridge's most imperiled plant.
"It would be such an enormous loss if the ecosystems of Florida were to disappear," Weekley says.
And "if you set out to save something, you have to save the parts."
Saving ziziphus is an effort joined by Bok, Archbold, the Nature Conservancy, Florida Museum of Natural History and Genetics Institute and others.
For a conservationist, ziziphus need do nothing to deserve attention. Ziziphus should live and die on evolution's timetable, not ours.
"It's important to protect the charismatic species like the Florida panther, but it is also incumbent on us to protect all the species," says Tricia Martin, Lake Wales Ridge program director for the Nature Conservancy. "When you start pulling out strings, you don't know what will unravel" in life on Earth.
"We're never going to be able to demonstrate immediate benefits of saving species." She says there is no question that we should.
Ziziphus needs rescuing.
The spiny shrub grows 3 to 6 feet tall, with shiny leaves, and yellow flowers in January and February. Plagued by a small population and poor health, ziziphus has few mates and even fewer successful unions.
Cuttings from wild ziziphus are nurtured at Bok, in planting beds and pots, a "captive population" for study and potential reintroduction to natural sites.
In 2002, 144 potted ziziphus and almost 2,000 seeds were planted at Lake Wales Ridge National Wildlife Refuge in Highlands County. While more than 8 of 10 transplants survived, only a handful of seeds did. Weekley and other researchers want to plant 300, 6-inch seedlings at Tiger Creek Preserve this spring.
The long-term goal, Weekley says, is plants in protected locations that reproduce unassisted.
Ziziphus survived millions of years.
Now its last, best hope is its human matchmakers.
Single, but lookingThe Bok-area site down the red clay road is protected, but hardly pristine. An abandoned skeet-shooting range is nearby. A housing subdivision multiplies beyond the trees. Ziziphus lives in a clearing crowded by pest plants, stands of bamboo, plum trees and palms, their seeds and roots trucked in with yard debris, their growth threatening to blot the sun. Overhead a small plane drones. The tat-tat-tat of a nail gun startles ancient ghosts.
"It's amazing this site survived. It may have been bigger than it was and this is all that's left," says Weekley of the roughly 60- by 30-yard clearing.
On this day in January, ziziphus is in bloom. Jeremy Ash, who drives the pickup, will hand-pollinate: the plant equivalent of fertility treatments.
Donning headgear with a magnifying lens, Ash folds his tall frame over a branch, carefully loosening a mesh bag enclosing a clump of flowers. The bag allows water and sunlight to enter but excludes insects to control the kind of pollen the flowers receive.
The blooms are so small they resemble fuzz. With magnification, Ash announces five buds have opened since his last visit. He knows because he marked each of his previous hand-pollinations with a dot of ink.
"On each flower, we remove the stamens," he explains. "Then we pollinate with pollen from another site."
Scientists have hand-pollinated ziziphus since 1997.
They've attempted more than 10,000 crosses.
Only 1 percent are successful.
"Quite often, if we cut open the pit, there's not a seed," Weekley says. "We (want) to understand why."
They have their theories. Ziziphus may be self-limiting due to resources: soil, nutrients, sun, space. Half the known sites are on privately owned pasture, subject to mowing, trampling by livestock and eradication as a weed. Fires sparked by lightning clear natural sites. So researchers now conduct controlled burns at Bok and other preserves, resulting in shoots sprouting from charred stumps.
The most likely culprit for ziziphus' plight is its abysmal sex life.
"It's always been rare. It's not been this rare," says Weekley.
What I like about youIn what researchers at the University of Florida believe is a first for an endangered plant, they are mapping ziziphus' reproductive genes. Variations in a gene are called alleles. The more alleles a species has, the more potential matches it can make. Diversity pays.
The minimum needed for a plant is two. Ziziphus has only three.
To complicate its love life, ziziphus is isolated from other ziziphus. It sends out root shoots. "They're really clones of itself," says plant conservation geneticist Matt Gitzendanner at the Florida Museum of Natural History at the University of Florida.
The clones, exact copies of the parent, do nothing to increase the gene pool.
"In many plants, there is self-pollination," Gitzendanner says. Not so ziziphus.
Ziziphus also suffers from "inbreeding depression": Ziziphus' partners are too closely related to invigorate the faltering species.
"We're looking at genetic variations in their population to see which types are compatible," Gitzendanner says. Weekley and others hope the plant's poor reproduction can be reversed if they can zero in on alleles and find the right gene combinations.
To survive as a species, ziziphus must produce many children. Strong ones. Who go forth and score.
Live and let liveIf Ziziphus celata were lost, there would be no disaster movie made. No melting ice caps. No raging plague.
Some of its relatives appear more useful. A member of the buckthorn family, or Rhamnaceae, its kin includes widely cultivated Ziziphus mauritiana, whose fruit appeals to birds and whose bark and roots are pounded into powders to treat stomachaches.
Other plants and animals on the IUCN list, including 16 in Florida, are more personable. The Florida scrub-jay takes a lifelong mate and almost flirts with humans. A gopher tortoise is perfection on a T-shirt.
But there is some greater good in protecting ziziphus, too, experts promise.
IUCN's credo is that human life is inextricably linked with the planet's biodiversity: Protection of all species is essential to humans' survival.
"If you start losing genetic diversity, the evolutionary potential goes away. If you say you don't need to preserve ziziphus, then you start whittling away" at the infrastructure of life on Earth, says UF's Gitzendanner.
Friedlander, the rancher, says she feels protective of her ugly friend.
"You have to understand their determination," she says, "to appreciate them."
Susan Aschoff can be reached at aschoff@sptimes.com or 727 892-2293.