Overnight parking is being banned along a popular beach road in an attempt to tackle problems caused by campers. From 5 May, parking will not be allowed between midnight and 0630 BST along 3km (1.9 miles) of Ferry Road at Studland.
The peninsula in Poole Bay, Dorset, is National Trust land and home to many rare species of reptiles and birds.
The trust said waste left by overnight campers in recent years had become a health risk, endangered wildlife and could lead to fires.
The road verge is a popular parking spot for visitors heading over to nearby Studland beach.
But the area around Ferry Road, which leads to the chain ferry that connects the Isle of Purbeck with Sandbanks in Poole, is a National Nature Reserve and a designated Area of Outstanding Natural Beauty (AONB).
Rare species that have made their home on the road verges and the surrounding heath and wetland include all six of Britain's native reptiles, the Dartford Warbler and more than 40 types of wildflowers.