Habitats of rare birds, butterflies and snakes have been destroyed by gravel thieves on protected New Forest heathland, the National Trust has said.
About 15 tonnes (1,500 kg) of gravel was taken from Rockford Common, a Site of Special Scientific Interest.
The area is home to species including smooth snakes, silver-studded blue butterflies and birds such as Dartford warblers and nightjars.
Police are investigating.
National Trust community ranger Jacob White said the area “contains some of the most internationally protected habitats and wildlife in Europe”.
“This greedy and selfish act has caused irreparable damage to wildlife habitats on the common, as well as extensive erosion of this rare heathland landscape,” he added.
Hampshire Constabulary and the trust, which manages the site, is appealing for any information about the theft which happened between 12:00 GMT on 15 March 09:20 on 16 March.