Calif. Wine Country Clashes With Ecosystem

Environmentalists Seek Larger Buffer Between Sonoma Vineyards, Waterways

In Sonoma County, the grape is king. But as California winemakers seek to capitalize on the popularity of their chardonnays and cabernets by spreading vineyards over as many acres as possible, they have steadily encroached on the rivers, streams and creeks that crisscross the scenic valley.

The rapid narrowing of the wooded corridors along these waterways worries wildlife specialists and environmental researchers, who say their studies show that these riparian, or streamside, lands play a complicated and vital role in the ecosystem, far beyond providing water for farmers and wildlife. But proposals to require wider corridors have run into heated opposition from vineyards.

"Vineyard expansion is costing native animals habitat needed for food, reproduction and seasonal migrations, and leading to increased erosion from barren riverbanks, and more sediment in streams," said biologist Jodi Hilty, of the Wildlife Conservation Society, who collaborated on a study that documented the streams' crucial role.

In many areas of Sonoma County, said Adina Merenlender of the University of California at Berkeley, riparian zones are now the only viable corridors linking undeveloped oak woodlands that serve as havens for wildlife in an increasingly fragmented landscape.

Although grizzly bears and wolves are long gone from northern California, said Andrea Mackenzie, general manager of the Sonoma County Agricultural Preservation and Open Space District, "the survival of other native animals like bobcats, foxes and coyotes could be threatened if vineyards are allowed to grow close to rivers and streams."

Streamside areas also support more than half of the reptiles and three-quarters of the amphibians in California. All told, 349 animal species rely on California's oak woodlands, most of which have creeks running through them -- and, in Sonoma County, vineyards growing along them.

Sonoma has already lost 70 to 90 percent of its riparian habitat, Mackenzie said. That worries biologist Caitlin Cornwall of the Sonoma Ecology Center, who says preserving broad corridors along streams produces dozens of benefits, including flood protection, good groundwater quality, and flourishing fish and wildlife populations.

Not surprisingly, proposals to require wider riparian corridors have triggered conflicts between environmentalists and vineyard owners.

At last count, Sonoma County boasted 190 wineries. More than 50,000 acres of grapes worth $375 million grow within its 52-mile-wide, 47-mile-long environs.

"With the value of vintners' collective investment in land here," said Jeff Lyon, a viticulturist at Gallo Vineyards, "we need to plant grapes on as much of that land as we can."

Wine growers have questioned the evidence marshaled by those pressing for wider corridors.

Nick Frey of the Sonoma County Grape Growers Association says that "the scientific basis to justify wide riparian setbacks, and the economic costs for landowners, have not been well considered. The setbacks will reduce farmers' income-producing acres and are likely greater than needed to filter sediment from runoff and preserve wildlife corridors."

To see how setback size affects wildlife, Hilty and Merenlender set remotely triggered cameras along 21 streams in six Sonoma County vineyards over two periods of several months in 1999 and 2000. Five corridors were "wide," with more than 2,200 feet on each side of a creek; seven were "narrow," with 65 feet on each side; and nine were "denuded," with vegetation covering 20 feet on each side.

The cameras showed that wide corridors were frequented by twice as many species as narrow or denuded corridors.