Ascending the first mile of the Mauna Loa trail, hikers should be on the lookout for young silversword plants. After disappearing for decades, ahinahina or Mauna Loa silversword, ( Argyoxiphium kauense ) once again grace the slopes of Mauna Loa in Hawai'i Volcanoes National Park. Today the National Park Service and its partners are striving to recover this icon of Hawaiian flora whose numbers had dwindled to fewer than 1,000 naturally occurring plants.
Hawai'i's silverswords are showy starlets of higher elevations, sending up a tower of tiny pink flowers from a ball-shaped rosette of silvery leaves . Usually flowering and producing seeds just once, silversword may live 30-40 years before producing a flowering spire. On Maui within Haleakala National Park, hundreds to thousands of the endemic Haleakala silversword flower each year to the delight of Park visitors. Yet, the last known historic record of silverswords in Hawaii Volcanoes National Park was a sighting by a European botanist in the 1920s, who reported them growing along the Mauna Loa trail, near Red Hill cabin. Browsing by goats, pigs and sheep most likely caused the decline of this endangered plant.
In the mid-1990s, several state, federal and private organizations formed a partnership to protect wild silversword and to propagate and outplant silversword seedlings. New fencing of the Park's sub-alpine and lower alpine zones along the Mauna Loa Strip area was completed, preventing browsing and trampling by feral goats, pigs and mouflon sheep. Due to the Park's now extensive, ungulate-free habitat, the Park became a centerpiece of this new silversword recovery program, targeted for massive outplanting of thousands of silverswords.
The Hawaiian Silversword Foundation and the Volcano Rare Plant Facility teamed up to propagate silverswords, assuring that outplanted populations had the maximum genetic diversity for long-term fitness and survival. Plant propagation plays an important role in recovery as large silversword populations are needed to insure species survival. Since silverswords flower just once, they require another plant for cross-pollination and successful seed set. Cuttings were taken from over 100 plants to the Volcano Rare Plant Facility where 96 flowered and produced seed for the Park's outplanting program and for a silversword exclosure at Kapapala Forest Reserve. Each plant seedling was tagged and is monitored yearly to determine survival and growth.
In 2005, Hawaii Volcanoes National Park boundaries were extended to include the 116,000 acre Kahuku Ranch, giving protected status to a population of wild silverswords growing on the southwest flank of Mauna Loa. Kahuku Ranch and Hawaii Division of Forestry and Wildlife employees have fenced over 700 silverswords. The Park has raised the fence to six feet to keep out mouflon sheep. Three plants in this population flowered last year and many more are poised to flower in 2005. The seed from these plants and cuttings will provide the founders and seed source for 5,000-7,000 outplantings over the next three years. To protect these outplantings, the Park will construct three fenced enclosures to protect young seedlings from mouflon sheep. Establishing new, protected silversword populations in Kahuku will substantially diminish the risk of extinction from not only sheep, but lava flows on Mauna Loa.
In just five short years, a cast of hundreds has mounted a heroic effort to save silverswords from extinction. The Park, its partners and dozens of volunteers, have constructed miles of fencing and outplanted thousands of silversword seedlings. Although the true measure of success will occur when these young silverswords start to flower, in just one to two years, an astounding 83% of the outplantings have survived. A once-dwindling treasure has become a living testament to the power of a committed group of agencies and individuals.