A fire in a conservation area near Alexandra was "wanton vandalism", destructive to soil, flora and fauna, conservationist Brian Patrick said.
An entomologist, who is also the director of Central Stories Museum and Art Gallery in Alexandra, Mr Patrick was disappointed at the damage to 20ha of the Flat Top Hill conservation area.
He was one of the proponents of the 813ha property becoming a conservation estate.
"It has a huge value.
It may look, to the untrained eye, to be lacking in diversity, but actually there's a higher diversity of plants there than in most New Zealand forests.
It also supports insects, lizards, plants and lichens, so there's a lot of diversity in these drylands."
"Sure, you need to get on your hands and knees to see some of the plants but it's all highly valuable and epitomises the landscape and values of Central Otago, with a bit of everything on display, from ancient soils and salt pans through to shrublands, spring annuals and rock tors."
Mr Patrick said people needed to be more careful in such a dry environment.
"People start fires, they don't just start themselves, so I'm disappointed that people can't be more careful and respect property. I'd describe the fire as wanton vandalism and it's ironic that there was a sign about the fire risk just across the road from the blackened property."
Fires were always disastrous, he said, and this one would also prove expensive to the taxpayer.
The Department of Conservation had done a good job looking after the land, clearing the weeds and controlling rabbits.
"Although it's a relatively small area that was burnt, it's a robust area and the vegetation will grow back, especially as it's ungrazed. Unfortunately though, the fire will encourage weeds."
