"Tourist" Bison Devastate California Island

Bijal P. Trivedi
National Geographic Today
December 17, 2001

Rumor has it that the bison that now wreak havoc on Santa Catalina, about a 15-minute helicopter ride from Los Angeles, California, were brought to the arid island as movie extras for the silent film The Vanishing American. This is a completely believable scenario given the island's proximity to L.A.—but for the fact that there are no bison in the film. Another theory is that the animals were originally brought to the island as a tourist attraction.

Whatever their origins, these majestic "invaders" are destroying Santa Catalina's fragile plant life and turning grassy areas into dust bowls. But exactly what should be done about the bison is controversial as they attract a steady stream of tourist dollars to the local economy.

"There is an ambivalent feeling about the bison on Catalina," said Deb Jenssen of the Catalina Conservancy, which oversees 88 percent of the island. "They are beautiful. They are incredible. We all love to see them, but when you see some of the impacts we say, oh boy, what are we going to do about this one," said Jenssen.

Originally there were 14 bison. Now there are almost 400 roaming the island, which is only 76 square miles (197 square kilometers)—an area just slightly larger than Washington, D.C.

The bison, which are natives of North America's Great Plains, have overwhelmed the island's resources as they devour the slow-growing grasses that cover the steep slopes. Grazing, trampling, and wallowing by the hefty animals have destroyed the vegetation in many areas, leaving the soil soft, crumbly, and exposed. Without plants and grass, the loose soil is vulnerable to erosion.

"The bison is a big animal that needs to eat a lot," said Jenssen. "The plants are not fast-growing plants that can recover from that kind of grazing and browsing."

Although the bison seem to be thriving on Catalina, there are signs that the herd size may be getting too large for the island to support.

Bison Eat Prickly Pear Cactus

"We have also witnessed bison eating prickly pear cactus fruit," said Jenssen.

Cacti are not typical fare for bison. Their diet consists only of grass. But whether the animal is merely adapting to local food sources or whether it is a sign of a desperate, hungry animal not finding enough grass to graze is unknown.

"There is a lot of material to contemplate when we introduce a foreign animal to a habitat, such as the potential implications of that introduction," said Jenssen.

The Catalina Island Conservancy is removing other nonnative animals such as pigs and goats in an effort to return the island to its natural state. But so far bison have been reprieved from deportation. Catalina receives over a million tourists every year—many who come specifically to see the bison.

Continued on Next Page >>


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