Hawaii has been awarded a grant worth nearly a half-million dollars to help it protect its native forests and drinking water supply, the U.S. Department of Agriculture said Wednesday.

Hawaii will use its $467,000 grant to help private landowners remove invasive species and plant native trees on their forested properties. Only landowners already participating in a watershed partnership with the state will be eligible to receive some of the money.

The funds will allow Hawaii to protect an additional 4,000 acres beyond existing plans, said Emma Yuen, the natural area reserves planner at the state Department of Land and Natural Resources.

The money is among $370 million the U.S. Department of Agriculture awarded to 115 conservation projects in all 50 states and Puerto Rico, the department said in a news release.

Hawaii’s grant supplements funds the state Legislature has already appropriated for watershed protection.

Forests are critical to the drinking water supply because they act like sponges, absorbing mist and rain, said Carty Chang, acting director of the state land department. The state must protect forests because rainfall and water supplies have been declining, and the trend is expected to accelerate with climate change.

"We must act now to protect forests to ensure water for people today and future generations," he said in a statement.

The state in 2013 allocated millions of dollars to boost native forests by removing invasive species and planting native trees. Funds are also paying for the installation of fences that will keep out feral pigs, goats and other grazing animals that destroy native forests.

The state says restoring forests is the most cost-efficient way to absorb rainwater and replenish groundwater. Restoring native forests also protects habitat for endangered species and helps prevent erosion, which can smother coral reefs after heavy rain.

Yuen said more than half of Hawaii’s watershed forests have been lost, particularly to grazing animals, fires and invasive plants like strawberry guava trees.

"Protecting what’s left is a priority to make sure we don’t lose any more ground," Yuen said at a news conference announcing the grant.