In an effort to keep more than 30 rare species of plants and animals from vanishing in Channel Islands National Park, federal biologists are developing a new strategy to protect the native flora and fauna before it's too late.

Scientists from the U. S. Fish and Wildlife Service and Channel Islands National Park are crafting a conservation agreement designed to prevent further decline of the native species on four of the park's northernmost islands.

As the plan is being developed, officials are considering removing or restricting some livestock and game animals that had been placed on the islands, and eventually weeding out non-native plants. Biologists may also nurture native species with some plantings.

A similar plan is being developed for the four southern Channel Islands by Fish and Wildlife's office in Carlsbad.

Much of the disturbance on the islands has been caused by grazing and browsing of game animals imported for hunters or livestock, including cattle, elk, deer, pigs and sheep, said Connie Rutherford, a botanist heading up the agreement development for Fish and Wildlife.

While most of the large grazing animals have already been removed from Anacapa and San Miguel islands, the other two islands covered by the conservation agreement, Santa Cruz and Santa Rosa, still host the large grazers.

The animals denude rare shrubs and disrupt top soil with their hoofs, allowing the more aggressive invasive plants and weeds to crowd out native grasses and plants, she said. That reduces the vegetation available to native animals as well.

"In a couple of decades, you can undo what nature took thousands of years to create," Rutherford said. "Putting the pieces back together is not so easy."

The new conservation plan will try to take a broader look at protecting species than the government has taken in the past.

"This is a much more comprehensive approach," Rutherford said of the conservation agreement. "We're looking at the whole habitat or the whole ecosystem rather than just isolated portions of it."

The developing agreement reflects the U. S. Department of Interior's new direction for implementing the 20-year-old Endangered Species Act, which comes up for congressional reauthorization this year.

Interior Secretary Bruce Babbitt has instructed the Fish and Wildlife Service to avoid "train wrecks" and "crisis management" in part through conservation agreements among agencies overseeing public lands. Those agreements should help protect habitat and preclude the need for placing species on the endangered list, the department said.