Hundreds of farmers, biologists, Native Americans and other ordinary citizens descended on the Riverside County government center today in an effort to derail a proposed granite quarry just half a mile from Temecula.

They told the Local Agency Formation Commission that Liberty Quarry would desecrate tribal land, pollute the air, destroy critical wildlife habitat and increase truck traffic on area roads.

The commission is expected to decide today whether to grant Temecula's request to annex the 5,000- acre site and in effect kill plans for the quarry. Commission staff has recommended that the request be denied and that the land remain in county hands.

More than 300 residents crowded into the hearing room, with several hundred others standing outside. Many wore green hats that read "ANNEX."

"For Granite Construction to rip open a mountain and gut it for 75 years and then say the quarry will have no impact is absurd," said Mike Jurkosky, who lives near the proposed site.

Others urged the commission to act for the public good, not in the interests of a private company.

Matt Rahn, who directs the Santa Margarita Ecological Reserve for San Diego State University, told officials that the quarry would cut off a critical wildlife corridor linking inland California to the coast. He also said it would threaten the Santa Margarita River, the last free-flowing river in Southern California.

"The reserve is an outdoor classroom and research center," he said. "This is how California looked 100 years ago. "

Mark Macarro, chairman of the Pechanga tribe, said annexing area would protect the place where tribal tradition says the earth was created and the tribe was born.

"This is our Eden," he said. "We cannot re-create where the world was created. There is only one Eden."

Supporters of the quarry are expected to speak this afternoon.