Landcare Australia has been "starved of funds" and needs more money and volunteers, the chair of the national conservation charity says.
Doug Humann, who will address a biennial conference in Sydney on Wednesday, told AAP the charity's funding had been slashed.
"The landcare program has been starved of funds in recent years, it's lost funds," Mr Humann said.
"We need to reinstate the level of funding for landcare, the National Landcare Program, it needs to be directed to landcare projects on the ground.
"The twin crises facing land and water management in Australia are climate change and biodiversity loss."
Conservationists, farmers and climate experts are meeting for the charity's biennial conference to discuss how Landcare is helping biodiversity and more sustainable farming systems in the face of a changing climate.
During a farm visit to a landcare project at Camden on the outskirts of Sydney on Tuesday, Mr Humann said the charity was reliant on volunteers and needed an injection of youth.
"What we need is more young people involved and we've got a particular program running at the conference that's focused on getting more youth into Landcare," Mr Humann said.
"It's always going to be heavily dependent on volunteers, and we encourage that, but it needs that government support as well."
One of those volunteers is Tony Biffin, who helped to plant some of the 22,000 trees that line the banks of the Nepean River at the Camden town farm in Sydney's south.
The dairy farmer spends about six hours a week volunteering at the council-owned property, where he helps manage the beef cattle herd.
"It comes from a love of ... the land here and the farm," he told AAP.
"It's all about sustainability and more sustainable agriculture."
Mr Biffin said the trees had helped stabilise the farm's river banks in the face of severe flooding this year, and had improved the property's biodiversity.
"It is an absolute haven for parrots ... and birdlife generally," Mr Biffin said.
"It's just beautiful down there ... I believe that the native species of birds are now going to dominate the scene."
The director of the Institute for Climate, Energy and Disaster Solutions at the Australian National University told the conference agricultural productivity has already been "hit big time" by climate change.
Professor Mark Howden told the conference that recent studies showed on average across the globe climate change had driven agricultural productivity down about 20 per cent.
"The challenges of feeding the world but looking after our land resources will just increase over time if climate change is let rip," he said on Wednesday.
Prof Howden said increasing global temperatures were already having an impact on food supply.
He said the battle for water was going to get more intense as climate change intensified.
"If we think we've got challenges in terms of competition for water between agriculture, environment, urban and industrial uses, this is just going to get far far more intense."
The national Landcare conference is being held in Sydney on Wednesday and Thursday.
