QEII National Trust covenanting landowners are together spending an estimated $25 million of their own money every year to protect native species, forests, and wetlands, a University of Waikato study has found.
The study was commissioned to estimate the cost effectiveness of conservation activity facilitated by the Trust.
The landowners, the majority of which are farmers, have made an overall financial commitment of up to $1.3 billion to protect the special areas of private and leased land since the QEII National Trust was set up 40 years ago.
The Trust Chair James Guild said the area being protected by covenants is still growing with a further 115 on track to be registered this year alone.
"With the release of this report we acknowledge the hard work, philanthropy, generosity, and passion of the thousands of landowners who have voluntarily elected to covenant special places on their land with the National Trust.
"Together they are making a very significant contribution towards the protection and enhancement of our threatened ecosystems and biodiversity on private land to ensure New Zealand's uniqueness is protected forever," he said.
The biggest cost for landowners establishing covenants was fencing the covenanted areas followed by initial weed control, restoration planting and wetland restoration work.