A part of the Buffalo Gap National Grasslands in southwestern South Dakota would be designated as a wilderness area under a measure introduced Wednesday by South Dakota Sen. Tim Johnson.

Johnson, a Democrat, said the measure would allow balanced, commonsense use of the area covering about 50,000 acres. However, the wilderness designation is likely to face continued strong opposition from some agricultural and outdoor recreation groups.

The bill would preserve the rugged area for the public by creating the nation's first wilderness area on national grasslands, Johnson said. Hunting, livestock grazing by ranchers who lease pastures, rock collecting and other activities would be allowed to continue in the area, he said.

"In listening to feedback from South Dakotans, I think this is a balanced approach to public access and making sure those who make their living on the national grasslands can still prosper," Johnson said in a telephone press conference with reporters.

Gov. Mike Rounds said he remains opposed to designating the area as a wilderness. In a letter to Johnson in January, the Republican governor said other wilderness areas have become infested with insects or developed other problems because they are not managed properly.

Once an area is designated as wilderness, groups try to prevent livestock grazing there, Rounds said. Federal officials already have authority to preserve the grasslands area by designating roadless areas, preventing development, limiting public access and protecting wildlife and plants, he said.

The senator said his bill is named in honor of Tony Dean, the nationally known outdoor enthusiast and conservationist who promoted South Dakota hunting and fishing in his television and radio programs. Dean, who lived in Pierre, died in 2008.

Johnson noted that the U.S. Forest Service, which manages the national grasslands, recommended in 2002 that areas in the Indian Creek and Red Shirt areas be given wilderness protection. He said his bill is based on that recommendation.

The area is near Badlands National Park, with some of it in the Cheyenne River valley. The rugged landscape includes badlands formations, buttes, valleys and mesas.

Johnson said the wilderness designation will not change efforts to control invasive insects or weeds, manage prairie dogs or fight wildfires in the area.

"Wilderness does not mean no management," he said.

Mike Held, chief executive officer of the South Dakota Farm Bureau, said the organization will continue to oppose the wilderness designation even if livestock grazing and other uses are allowed. Management can change in wilderness areas, he said.

Held said last year that he viewed the destruction caused by mountain pine beetles in a wilderness area in the Black Hills.

"It's appalling to watch a resource go to pot like that because of lack of management. This would hold the same prospect," Held said.

Johnson said the grasslands area should not be compared with the Black Hills wilderness area because the two are totally different landscapes.

Cheryl Warren of Custer, manager of the South Dakota Wild Grassland Coalition, said support has been growing for giving wilderness protection to the areas in the grasslands. The proposal would protect public land for the benefit of everyone in the nation, she said.

"We're happy about it," Warren said. "We understand there are varying perceptions about it and not everybody is going to be thrilled about it. But you can't really get anything done that everybody is going to be happy about. We're happy the majority of people can see this is a good thing."

Republican Sen. John Thune did not endorse Johnson's bill, saying any effort to designate the area as wilderness must involve local residents who would be most affected.

"As a hunter, I understand Sen. Johnson's desire to honor Tony Dean's memory in this way, but the areas proposed for wilderness designation are already protected by the federal government," Thune said in a written statement.

Copyright 2010 The Associated Press.