Human feces, overflowing garbage, illegal off-roading and other damaging behavior in fragile areas were beginning to overwhelm some of the West's iconic national parks on Monday, as a partial government shutdown left the areas open to visitors but with little staff on duty.

"It's a free-for-all," Dakota Snider, 24, who lives and works in Yosemite Valley, said by telephone Monday, as Yosemite National Park officials announced closings of some minimally supervised campgrounds and public areas within the park that are overwhelmed.

"It's so heartbreaking. There is more trash and human waste and disregard for the rules than I've seen in my four years living here," Snider said.

The 10th day of the partial federal government shutdown, which has forced furloughs of hundreds of thousands of federal government employees, has left many parks without most of the rangers and others who staff campgrounds and otherwise keep parks running.