A record $55m has been spent by the Nature Conservancy to buy two cattle stations along the Murrumbidgee River near Balranald in New South Wales to preserve valuable wetlands, known as the Great Cumbung Swamp, that are a major breeding ground for birds.

The properties, which adjoin the NSW-government owned property, Gayini-Nimmie Caira and the Yanga national park, near Balranald, have been bought through a partnership with an agricultural investment company, Tiverton.

It is is one of the most ambitious private conservation efforts attempted in Australia and together the three areas will result in more than 200,000 hectares of land being under protection. The area has been under constant threat of being converted to irrigated cropping.

The Juanbung and Boyong cattle stations, along with the properties’ water rights, will be managed in conjunction with Nimmie-Caira.

This will result in the protection of almost the entire extent of the Great Cumbung swamp.

Juanbung and Boyong cattle stations will be managed by TNC and the Nari Nari tribal council. Photograph: Peter Stephen

“Cumbung is one of the largest and most important wetlands in the Murray-Darling Basin. It is home to 131 bird species and more than 200 plant species and is uniquely located at the confluence of the Lachlan and Murrumbidgee rivers,” Nature Conservancy’s Australian director, Rich Gilmore, said.

“Today, more than ever, we need science-based, pragmatic solutions that deliver benefits for people and nature. If we are to save the basin’s rivers and the communities that depend on them, conservationists, irrigators and governments must come together and act with courage, urgency and optimism,” he said.

In addition to wetland conservation and water recovery, Tiverton will manage the property for the dual objectives of conservation and sustainable agriculture.

Like Nimmie Caira, this is likely to be for sustainable grazing in less sensitive areas.

“This will ensure jobs continue in the Riverina,” said Gilmore.

Tiverton’s director, Nigel Sharp, said the property would be managed for sustainable farming and the company would be exploring other options such as carbon and biodiversity offsets and ecotourism.

The Great Cumbung will be managed in conjunction with the 87,000-hectare Gayini Nimmie-Caira property, which was purchased for conservation by the NSW government in2012 and is now managed by the Nature Conservancy and Nari Nari tribal council.

The chair of the tribal council, Ian Woods, said: “Nari Nari people are very supportive of the purchase and we look forward to working with TNC and Tiverton at the Great Cumbung and Gayini Nimmie-Caira.”

The TNC’s work in the Murray-Darling is being supported by John B Fairfax , The Ian Potter Foundation, the Besen family and the Baillieu Myer family’s Yulgilbar Foundation. Funding was also provided by the US-based Wyss Foundation and the Wyss Campaign for Nature. Debt finance was provided by ANZ.

The Nature Conservancy is a global conservation organisation dedicated to conserving the lands and waterways.