Conservationists have spent 15 years encouraging butterflies to visit Hoe Grange Quarry, which was last mined in 1990 and is currently managed by Derbyshire Wildlife Trust, external.
More than two dozen different types of butterfly have been observed at the site, including the rare Wall butterfly whose numbers have declined by 87% over the past 40 years.
Ken Orpe, Derbyshire butterfly recorder for Butterfly Conservation, said volunteers were left distraught after large areas of wildflowers which attract the insects were covered with mounds of earth by the quarrying company.
“There was a slight rockfall on the far side of the quarry last year and this has resulted in an over-reaction to resolve the issue,” he said.
“The area’s been cut off and we’ve just wasted 15 years of our lives”.
Orpe added a recent survey showed the number of butterflies observed had fallen dramatically since the mounds were created.
“During our survey in 2025 we recorded around 200 butterflies. This year we spotted just 20 and most of them were on the nearby buddleia bushes we had planted, which thankfully were not affected,” he said.