The Nature Conservancy, a conservation group that preserves wildlife habitat around the globe, announced Wednesday it acquired another square mile of land on the Strawberry River near Heber City.

Simultaneously Wednesday, all 3,070 acres of the Conservancy's holdings along the Lower Strawberry River were purchased by the U.S. Bureau of Reclamation for more than $1.6 million. The land will be turned over to the state as a wildlife preserve.With the latest 640 acres acquired west of the Strawberry Pinnacles in Duchesne County, the Conservancy has completed the acquisition of an eight-mile stretch of the river. It hopes to get 10 miles more.

Meanwhile, the bureau is paying back the conservationists' investment of more than $1.6 million, using money appropriated to mitigate wildlife impacts of the Central Utah Project.

The complex transaction will ensure the preservation of the stretch, according to Dave Livermore, regional director of The Nature Conservancy.

In March, the Conservancy bought 1,730 acres. Two weeks ago, the state of Utah was reimbursed $200,000 by the U.S. Bureau of Reclamation for money the state contributed for the initial purchase of 700 acres in July 1987.

"Today's closing represents a landmark effort to preserve one of Utah's most outstanding natural areas and wild trout fisheries," Livermore said. He hailed the conservation partnership among the Conservancy, the bureau and the state.

The group is also grateful for "the strong endorsement this project has received from the Utah Delegation in Washington," he said.

Clifford I. Barrett, regional director of the Bureau of Reclamation, said the agency is pleased to be a partner in the protection of such an important segment of the river.

"This pristine section of Strawberry River, and its outstanding fish and wildlife values, will now be preserved for the benefit of the public," Barrett said. "We acknowledge The Nature Conservancy, which moved quickly at a critical time to purchase these lands when Reclamation funding was not available."

The bureau's spokesman in Salt Lake City, Barry Wirth, said, "To us it was a substantial investment of money . . . It was a pretty significant action."

"This is the first eight miles in what we hope will be an 18-mile project," said Chris Montague, assistant director of the Conservancy's Great Basin Field Office in Salt Lake City. The preservation effort is intended to someday stretch along the river corridor from Soldier Creek Dam east to the Strawberry Pinnacles.

"It'll be managed as a fly-fishing only, Class 2 stream," he said. Public access will be permitted, but probably not camping.

The Bureau of Reclamation will ask the Utah Division of Wildlife Resources to develop a management plan for the eight miles already protected. As soon as the plan is approved, title to the stretch will be signed over to the DWR, he said.

Don Olsen of the bureau said, "The portion which includes the eight miles was part of our mitigation plan. It was approved by all the wildlife agencies."

The bureau hopes to acquire easement for access to the public for the remaining 10 to 12 miles to Soldier Creek Dam, he said. The bureau has not made a commitment to repurchase that stretch if the Conservancy buys it too.

In one year, contributions in money and land gifts to the Conservancy amounted to more than $73 million.