State environmental leaders and conservation groups have announced a $3.5 billion project to help preserve and protect Minnesota’s prairies.

The Star Tribune reported Wednesday (http://bit.ly/Pmc6uu ) that the 25-year plan includes an agreement for state and federal agencies, and conservation groups, to work together to acquire or protect more than 2.2 million acres of prairies, wetlands and grasslands on the western edge of the state.

Department of Natural Resources Commissioner Tom Landwehr said only 1 percent of the state’s native prairie still exists, and what remains may soon disappear as well due to pressures of development and advances in agriculture.

“We can see the trend line of where this is going,” he said. “We are not going to get ahead of it, but we have to get as much protected as we can.”

The state can use sales tax revenue from the state’s Legacy Amendment to get money to buy land and keep it as prairie, Landwehr said. The amendment, approved in 2008, raised the sales tax slightly to fund four areas: the outdoors, clean water, arts and culture, and parks and trails.

The new plan calls for $1.1 billion in Legacy funds plus $2.5 billion from other sources over 25 years.

State officials said state and federal agencies and conservation groups like the Nature Conservancy, Pheasants Forever and the Audubon Society all have agreed to the same plan, which will increase the chances for success.

Grasslands help preserve clean water and prevent soil erosion. Perennial prairie plants have roots extending many feet into the ground, filtering water and soaking it up before it runs off the land.

“Water purification and filtration and flood retention are important for grasslands, but prairies are best,” said Steve Chaplin, director of prairie conservation for the Nature Conservancy.

Chaplin said the project also will help preserve thousands of plant and animal species that depend on the prairie.