Reintroducing Hawaii’s by Robert Robichaux, Steven Bergfeld, Marie Bruegmann, Joan Canfield, Patrice Moriyasu, Tanya Silverswords Rubenstein, Timothy Tunison, and Frederick Warshauer Of the many endangered plant lates, however, the Mauna Loa species in the Hawaiian Islands, silversword suffered a severe decline. silverswords have the highest profile The surviving individuals, numbering due to their radiant beauty and the fewer than 1,000 plants, are confined to severity of the threats confronting them. three small natural populations widely The large-scale reintroduction of scattered across Mauna Loa. greenhouse-grown seedlings is raising In addition to direct threats from hopes for the recovery of these spec- alien ungulates, Mauna Kea and Mauna tacular endemic species, although Loa silverswords may face serious serious challenges remain. indirect threats from alien insects, The Mauna Kea silversword especially ants and wasps. These alien A Mauna Loa silversword being planted at Kulani Correctional (Argyroxiphium sandwicense ssp. predators have the potential to decimate Facility. Inmates from the facility sandwicense) had an historical range populations of native bees and moths have participated in an innovative that encircled Mauna Kea volcano at that serve as pollinators, thereby greatly volunteer program to help with 8,500-12,500 feet (2,600-3,800 meters) limiting seed set in silverswords. silversword reintroduction. elevation on the Island of Hawai‘i. All photos by Joan Canfield Based on the records of early natural- Partnership for Recovery ists, this silversword grew in abundance Though the threats are daunting, the and was a dominant plant of the outlook for recovery of Mauna Kea and subalpine and alpine ecosystems. In the Mauna Loa silverswords has brightened late 1700s, European voyagers intro- considerably in recent years. Key to this duced sheep and other alien (non- reversal of fortune has been a public/ native) ungulates to the island. The private partnership between the Volcano (Opposite page, bottom) Members of alien animals spread rapidly, with the Rare Plant Facility, Hawaii Division of the sunflower family (Asteraceae), sheep population on Mauna Kea Forestry and Wildlife, Fish and Wildlife silverswords have a rosette form, eventually exceeding 40,000. As alien Service, National Park Service, Biologi- with dagger-shaped leaves that are ungulate populations increased, cal Resources Division of the U.S. densely covered by silvery hairs. silverswords declined severely in Geological Survey, and Hawaiian Most silverswords flower only once, distribution and abundance, presumably Silversword Foundation. The Rare Plant after growing for 30-50 years, with due to heavy browsing. The small the majestic flowering stalks of Facility has grown the large number of large rosettes often exceeding 1.5 natural population of silverswords that silversword seedlings destined for meters in height. persists on Mauna Kea now contains reintroduction, closely tracking the only 42 plants, all of them confined to pedigree (or parentage) of each one. cliffs and rock faces that are inacces- Different agencies in the partnership sible to ungulates. have then overseen the outplanting The Mauna Loa silversword effort in different parts of the historical (Argyroxiphium kauense) suffered a ranges. The non-profit Silversword similar fate. Historically, this species was Foundation has worked closely with all common in moist to wet ecosystems of the partners to facilitate the collabo- between 5,000 and 8,900 feet (1,500 rative initiative. By sharing expertise, and 2,700 m) on Mauna Loa and resources, and enthusiasm, and by Hualalai volcanoes. Following the emphasizing on-the-ground actions, the introduction and spread of pigs, partnership has made major strides mouflon sheep, and other alien ungu- recently with silversword reintroduction. 22 ENDANGERED SPECIES BULLETIN MAY/JUNE 2000 VOLUME XXV NO. 3 In 1999, we outplanted more than The major threat to the recovery of 2,500 silverswords on Mauna Kea, silverswords (and many other endan- bringing the total reintroduced popula- gered plant species in Hawaii) contin- tion to about 4,000. (About 1,500 ues to be alien ungulates. Even at low Mauna Kea silverswords were success- numbers, these animals can have severe fully outplanted by the Division of impacts. On the upper slopes of Mauna Forestry and Wildlife between 1973 and Kea, for example, where alien ungulate 1998.) We planted the seedlings at populations have been greatly reduced multiple sites in the State Forest Reserve. by a court-ordered removal program, Survivorship has varied among the sites browsing still caused significant seedling and with the time of planting, but has mortality, and serious damage to adult been exceptionally high in some cases. silverswords, at some of the outplanting Of the 1,200 seedlings planted in late sites in 1999. Because alien ungulates fall on the east slopes of Mauna Kea, are still abundant on Mauna Loa and for example, more than 99 percent have Hualalai, all of our outplanting sites for survived their critical first 9 months on Mauna Loa silverswords must be the volcano. protected by fencing, which ultimately We also outplanted more than 1,000 constrains the scope of the reintroduction silversword seedlings on Mauna Loa effort. Alien insects may also continue and Hualalai in 1999. They went to to pose a significant threat to the health The Volcano Rare Plant Facility is part of the Center protected sites in Hawaii Volcanoes of native pollinator populations. for Conservation Research and Training of the National Park, Kulani Correctional The large-scale reintroduction University of Hawaii. In addition to growing Facility, and State Forest Reserves. strategy for silverswords, implemented thousands of silversword seedlings for Again, survivorship has varied among through our public/private partnership, reintroduction each year, the facility has the sites, but has exceeded 90 percent at highlights both the opportunities and successfully propagated more than 70 other endangered and threatened plant species from the some locations. challenges for recovery of other Island of Hawai‘i. To ensure high genetic diversity in endangered plant species in Hawaii. the reintroduced silversword popula- tions, we have implemented a con- Robert Robichaux is President of the trolled crossing program in which we Board of Trustees of the Hawaiian hand-pollinate flowering silverswords in Silversword Foundation. Steven Bergfeld both the field and greenhouse to is a Forester with the Hawaii Depart- produce seeds (see Bulletin Vol. XXIII, ment of Land and Natural Resources, No. 2-3). Although hand-pollinating the Division of Forestry and Wildlife. Marie plants can be challenging at times, Bruegmann is a Botanist with the Fish especially on Mauna Kea, where we and Wildlife Service’s Pacific Islands must perch precariously on steep cliffs Ecoregion Office. Joan Canfield is and rock faces, the program has Deputy Director of the Pacific Island enabled us to significantly increase the Ecosystems Research Center (USGS/BRD/ number of founders (or parents) for the PIERC), U.S. Geological Survey, Biologi- reintroduction effort, and to balance cal Resources Division. Patrice Moriyasu their genetic representation among the is a Horticulturist with the University of seedlings that are outplanted. Hawaii, Center for Conservation Over the next year, we plan to Research and Training, Volcano Rare outplant another 2,000 silverswords on Plant Facility. Tanya Rubenstein is Mauna Kea and 8,000 silverswords on Olaa-Kilauea Partnership Coordinator Mauna Loa and Hualalai. Thus, we will at Hawaii Volcanoes National Park soon be about 40-60 percent of the way (HAVO). Timothy Tunison is Chief of towards achieving our long-term goal of Resources Management at HAVO. reintroducing more than 15,000 Mauna Frederick Warshauer is a Botanist with Kea and Mauna Loa silverswords USGS/BRD/PIERC. throughout their historical ranges. ENDANGERED SPECIES BULLETIN MAY/JUNE 2000 VOLUME XXV NO. 3 23.