The negative impacts caused by invasive species on Hawaii’s natural and cultural resources came into special focus this past week, the third annual Hawaii Invasive Species Awareness Week.
The awareness program is part of the Hawaii Invasive Species Council, which I co-chaired while serving as director of state Department of Land and Natural Resources.
In Kailua-Kona on Hawaii island, the Kaloko-Honokōhau National Historical Park’s premise for its petition for a state groundwater management area designation is that water withdrawal from wells in the mauka high-level aquifer will impact the makai anchialine ponds, fishponds and Native Hawaiian practices.
While focusing on that premise, though, the national park has ignored its invasive species problem for years.
Kaloko-Honokōhau’s own 1974 Spirit Report and plan noted the need to "eradicate the exotic vegetation … which now dominate the area."
Vegetation analysis reports were conducted in the park in 1990, 1996 and, most recently, in 2011. In 1990, the vegetation assessment found that 39 species — or 53 percent of all species in the national park — were alien, many of them invasive.
An updated inventory conducted in 1996 reported that the alien species in the park increased from 39 plant species to 80 plant species. More alarming, the ratio of alien-to-total species increased from 53 percent to 69 percent.
Kaloko-Honokōhau National Park was — and is — dominated by alien plants. And these plants are having negative impacts on that park’s resources, including its anchialine ponds and fishponds.
A Dec. 31, 2014, National Park Service (NPS) record reports, "Alien vegetation is causing extensive damage to archaeological sites, including toppling walls, uprooting foundations, obscuring petroglyphs and disturbing midden deposits."
"In addition to damaging archaeological sites, invasive vegetation is extremely dense, obscuring visibility and preventing access to sites making it impossible to locate, map and document sites."
Nearly 100 acres of the 600 acres of the national park are covered with kiawe. In 2014, the University of Hawaii Economic Research Organization (UHERO) noted kiawe is not good for groundwater quantity or quality. Its report noted, "The groundwater uptake of an invasive species detracts from the aquifer stock. The model’s application to the Kona Coast (Hawai‘i) showed that kiawe management can generate a large net present value for groundwater users."
In layman’s terms: When you remove the kiawe, there will be more fresh groundwater.
Kaloko-Honokōhau National Park claims reduction in groundwater is a negative impact on its resources, yet nearly 20 percent of its land area is covered with kiawe — and there are no signs that the park is seeking the immediate removal of this negative influence.
Perhaps it’s time for Kaloko-Honokōhau National Park to follow its own 1974 Spirit Report and 1994 Management Plan actions, and remove the invasive species and restore the native vegetation in the park. This will have a profound positive effect on the park’s groundwater.
In Kona, a question of growing concern is: Why won’t Kaloko-Honokōhau National Historical Park do its part to enhance the groundwater by removing the invasive species?