California Vineyard Expansions Hurting Wildlife?

Stefan Lovgren
for National Geographic News
February 24, 2004

The cost of producing wine may be higher than what price tags on bottles show. According to a recent conservation study, the rapid expansion of California's vineyards also inflicts a serious cost on the state's rich wildlife.

While the elimination of native oak forest habitats has already wiped out some animals, such as grizzly bears and wolves, researchers say that the survival of other native predators—among them, bobcats, foxes, and coyotes—could now be under threat.

In the report, which was published in the journal Conservation Biology, the scientists urge California wine growers to protect, and ideally expand, corridors of natural vegetation, especially along the many streams that run through the vineyards.

"If they're not careful about land-use planning and maintaining connectivity for wildlife that need large areas to survive, we're likely to see more species go extinct," said Jodi Hilty, a scientist at the Bozeman, Montana, office of the Wildlife Conservation Society, and the lead author of the report.

Connecting Wildlife

For the study, the researchers set remotely-triggered cameras in 21 areas in six California vineyards. Their goal: to find out if corridors of natural vegetation help maintain connectivity in wildlife populations.

Among the animals detected by the cameras were bobcats, coyotes, gray foxes, raccoons, and striped skunks as well as non-native species such as possums, domestic cats, and dogs.

The researchers found that wide streamside corridors are indeed very important for native predators, which were 11 times more likely to be found along streams than in the vineyards. Other native species primarily used wider streamside corridors and were not detected in narrower or denuded corridors.

In contrast, non-native species, especially domestic cats, were found primarily in wide expanses of vineyards and along denuded corridors.

"We found that not only do corridors help maintain connectivity in wildlife populations, but the width of the corridor also determines if species will use these zones," said Hilty, who was a graduate student at the University of California, Berkeley, when she conducted the field research.

Hilty found that non-native species were much more active, and perhaps more abundant, almost replacing some native species. The cameras never detected some species that are believed to still exist in the area, such as black bears, long-tailed weasels, ringtails, badgers, and spotted skunks.

"In a larger sense, the landscape configuration of natural areas and vineyards is going to impact what species are able to remain in that landscape," Hilty said.

Continued on Next Page >>


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