Efforts to save endangered silversword an initial success
National Park Service officials said Wednesday the critically endangered Ka‘u silversword is staging a comeback within Hawaii Volcanoes National Park, thanks to decades of collaborative conservation efforts and a stroke of luck.
National Park Service biologists and partner agencies have reestablished the endemic silver-leafed plants at Kilohana, a high-elevation haven on the slopes of Mauna Loa.
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A few years ago, a member of the park’s fence crew spotted a wee rosette-shaped plant growing in the dry, rocky ground. The plant turned out to be a tiny ‘ahinahina (silversword).
It was a chance discovery that confirmed Ka‘u silverswords (Argyroxiphium kauense), while exceedingly rare, were present in the park’s upper Kahuku Unit miles from any known populations.
Five more plants were found during follow-up surveys.
“That was one of the best texts I’ve ever received,” recalled Sierra McDaniel, HVNP’s natural resources program manager. “We were already reintroducing plants at two sites on Mauna Loa, but to think there could be a third population really galvanized our enthusiasm.”
While Kilohana and the other remote, protected areas are closed to the public, a new digital storymap produced by the park shares the story of intense efforts and collaboration across generations to protect the Ka‘u ‘ahinahina and the ecosystems in which they grow.
At Kilohana, park biologists and conservation partners planted 330 young silverswords and more than 152,000 seeds within a protected fenced area between October 2021 and October 2022. So far, the initial survival rate of the plants is 97%.
That’s good news for a plant that blooms once, then dies.
“One of the reasons the initial survival rate is so high is because Kilohana is fenced, and that prevents invasive nonnative goats, sheep and pigs from coming in and devouring the ‘ahinahina,” McDaniel said. “Fences are our best ally in protecting endemic plants and ecosystems.”
Partner agencies in the effort to save the Ka‘u silversword include: University of Hawaii Pacific Cooperative Studies Unit; U.S. Geological Survey; Hawaii Division of Forestry and Wildlife; Hawaiian Silversword Foundation at the University of Arizona; U.S. Fish and Wildlife Service, Pacific Islands Office; Kupu; Three Mountain Alliance; and the Hawaii Plant Extinction Prevention Program.
