Solo hikers or groups of fewer than eight people will not have to obtain the permits, which will cost $50 and be required from April 12 to April 30.

No permits will be issued on weekends, and no groups of more than 12 people will be allowed. Permits may be obtained via Recreation.gov .

Sixty-two plants were trampled and visitors created nearly 400 feet of new “social trails” in Whiteoak Sink in the spring of 2016, according to park monitors. Park managers have since implemented strategies — like the recent permitting requirement — to limit the damage.

Park volunteers are also on hand to educate visitors about the need to stay on established trails and prevent free-ranging photographers from destroying the flowers they came to photograph.

These efforts have reduced trampling by 80 percent, but soil compaction and the creation of new trails are still problems, according to the park service.

Park scientists and others are also monitoring bats that hibernate and roost in area caves, including the prominent Blowhole Cave in the hollow. The area has been closed in the winter to prevent further disturbance to bat populations suffering from white-nose syndrome, a fungus that disrupts bat hibernation.

The fungus causes bats to emerge from hibernation at inappropriate times, and infected bats were reportedly flying erratically and diving toward people during the winter.

The populations of resident bat species have plummeted to such a low level, however, the park service eliminated that rul