Concerned about ongoing threats to Hawaii’s freshwater resources, U.S. Sen. Mazie Hirono held a hearing at the state Capitol on Tuesday about efforts to maintain the health of the state’s watersheds and opportunities for further collaboration.

Forested watersheds are critical to maintaining groundwater resources that the state relies upon for the vast majority of its public water supply. Scientists have warned that the watersheds are under threat from invasive species, hoofed animals such as goats and pigs, the expanding population and decreased rainfall — all of which is being exacerbated by climate change.

“Climate change will accelerate these issues and create new ones,” Hirono warned in opening comments. “As temperatures continue to rise, we face the prospect of saltwater intrusion into groundwater, as well as increased evaporation and drought.”

Hirono, who called the session to hear from elected state officials as well as federal and local agencies, cited troubling statistics:

>> The Pearl Harbor aquifer, which supplies over 60 percent of Oahu’s municipal drinking water, has shrunk by 50 percent compared with levels measured in 1910.

>> In East Hawaii, forests of strawberry guava, an invasive species, reduce groundwater recharge by 85 million gallons per day, or the equivalent of about 128 Olympic-size swimming pools.

“The stakes are clear,” said Hirono. “We need a holistic approach to water security to protect our forested watersheds.”

The two-hour panel of state officials and watershed experts was primarily a listening session about efforts underway to safeguard the state’s water resources.

GOV. David Ige highlighted the state’s goal of protecting 30 percent of Hawaii’s priority watershed forests by 2030; he said currently about 15 percent are protected.

“We can only reach this goal and go beyond it through public-private partnerships of landowners and managers who recognize that the best way to protect our forest watersheds and the source of fresh water is through collaborative management across landscapes,” said Ige.

A salient concern among panelists was a fungal disease devastating native ohia trees on Hawaii island. Rapid ohia death is afflicting more than 47,000 acres of native forests, according to state officials. Hirono suggested that might be an area in need of increased federal resources.

“It really is a scary issue,” said David Smith, administrator of the Hawaii Department of Land and Natural Resources’ Division of Forestry and Wildlife. “Ohia is the keystone species of the Hawaiian forests. Losing it would be devastating.”