Research into a conservation area in Western Australia's Wheatbelt has revealed the site contains about half the region's wildlife species.
Charles Darwin Reserve covers nearly 700 square kilometres of land but represents just one per cent of the mostly cleared Avon-Wheatbelt bio-region.
Bush Heritage has analysed five years of data and says the reserve is the most significant flora and fauna refuge in the area.
The group's spokesman Jim Radford says the findings show that a decade of conservation work in the reserve has been worthwhile.
"It's the last remaining unfragmented, continuous native vegetation in the landscape," Mr Radford said.
"Many of these species aren't found nationally."
Mr Radford says the high concentration of mammal, reptile and bird species in the area has significance beyond WA.
"Basically what we find in Charles Darwin Reserve, as part of the Avon-Wheatbelt in the South Western Botanical Province, is nationally important," he said.
"As a property that's being managed exclusively for conservation purposes, it's a jewel in that part of the world."