When a Weed Isn’t Just a Weed
At first glance, this could be a convention of gardeners.
People mill around displays in the hotel lobby, scrutinizing photos of lush, green-leaved vines and flower-dotted hillsides. They sit scribbling notes in seminars about aesthetic-sounding plants like yellow star thistle, fennel and Cape ivy.
But the experts are here not to praise these plants but to fight them.
Biologists and others gathered in Ontario this weekend for the annual meeting of the California Exotic Pest Plant Council, a nonprofit group committed to fighting so-called invasive nonnative vegetation, which can wreak havoc with the fragile balance sustaining the state’s native plants and animals.
To those on the front lines of this botanical battle, the future of the natural environment in Orange County and all of California is at stake.
“From where I stand, it appears we’re in the midst of what I can only call a botanical revolution,” warned one speaker, Andrew Sanders, herbarium coordinator at UC Riverside.
Sanders urged the council to pay more heed to exotic grasses sweeping some inland areas of Southern California, disrupting coastal sage scrub that is home to rare songbirds and other threatened native wildlife.
The audience murmured at his slides documenting how stretches of Riverside County sage scrub and chaparral were virtually transformed in only a few years to yellow, rippling grasslands.
Amid the bad news, however, some members are heartened that a problem once taken seriously only by specialized groups like their own is drawing heightened public attention and even prompting high-level talks in Washington.
A federal interagency task force has made recommendations to the White House on how to control invasive plants and animals.
“Clearly, the problem is accelerating,” said A. Gordon Brown, invasive-alien-species coordinator for the U.S. Department of the Interior, who gave the keynote address to the council. “Invasive plants and animals not only disrupt natural ecosystems but can cost formidable amounts of money to control.”
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To those at the pest-plant conference, the enemies are many.
Tamarisk from Eurasia now sucks up precious water in the desert, endangering rare birds and butterflies. A South African ivy creeps through canyons. A serpent-like plant called hydrilla, cultivated for the aquarium industry, has surged through Florida’s waters, costing millions of dollars in controls, and has cropped up in isolated spots in California.
Several speakers pinpointed a giant reed well known in Orange County, where volunteers and experts alike are growing adept at wrestling with towering stalks in choked waterways. The notorious Mediterranean reed, called Arundo donax, can crowd out native willows and cottonwoods as well as the bird called the least Bell’s vireo.
Those working to preserve Orange County’s wild lands fear other invaders as well. The artichoke thistle invades such open lands as Crystal Cove State Park and the Audubon Starr Ranch Sanctuary, and nonnative mustards turn coastal hills yellow in the spring.
What worries many California naturalists is that in a state with more than 230 plants and animals already on the federal endangered-species list--more than any other state except Hawaii--the spread of invasive plants could weaken more native plants and the birds, butterflies and tortoises that depend on them.
Reflecting early worries about invasive plants, the state’s pest-plant council grew out of a 1992 meeting in Morro Bay of academics as well as people working to preserve wild lands who found themselves struggling to control the weeds.
“We quickly found out that while we had tremendous biodiversity, we were losing it,” recalled Mike Kelly, the council’s founding secretary and a leader of Friends of Los Penasquitos Canyon Preserve, a San Diego County group.
Council membership has swelled to more than 600, and the symposium this weekend drew a mix of wildlife reserve managers, public park employees, university faculty, native-plant enthusiasts and representatives of federal, state and local agencies. Several other states, including Florida and Tennessee, have similar councils.
Some say that enthusiasm for protecting native plants is now spreading to the general public.
As the experts met at the Ontario Airport Hilton on Saturday, Orange County residents flocked to the UC Irvine arboretum for the annual fall plant sale sponsored by the county chapter of the California Native Plant Society. Such sales have become popular among gardeners who prefer filling their yards with native plants rather than exotics featured at many conventional nurseries.
While some fight for native vegetation in local streams, parks and their own backyards, others are working toward a coordinated nationwide effort to ward off the effects of fast-spreading invasive plants.
Some longtime pest council leaders said they are heartened that awareness is growing.
“It’s most evident in that Washington, D.C., is getting the message. That’s the best barometer,” said council President Michael Pitcairn.
“The cost is starting to penetrate,” said Kelly, who believes the notorious zebra mussel--a tiny mollusk that invaded waterways from the Great Lakes to the Mississippi River basin--has served as a wake-up call on the ecological and financial damage wreaked by nonnative animals and plants.
“Boy,” he said. “This problem has just been knocking at our door.”
