The ʻāhinahina, or Haleakalā silversword (Argyroxiphium sandwicensis ssp. macrocephalum) is an important part of the biocultural landscape of Haleakalā. It is endemic to the summit of Haleakalā, and the predominant plant species of alpine aeolian cinder desert. Adaptations such as fuzzy silver hairs, deep-set rosettes, and condensed gelatinous leaves make the ʻāhinahina extremely drought, sun, and cold-tolerant, allowing them to survive the harsh alpine environmnet of the Haeakalā summit (Carlquist 1980).
As one of the few plants dominant in the alpine landscape of Haleakalā summit, ʻāhinahina provide food and shelter for native insects and arthropods. They are also counterparts of native pollinators such as the yellow-faced bee (Hylaeus anthracinus).
ʻĀhinahina are large, charismatic rosette plants, and an iconic endemic species of Haleakalā National Park. Visitors from around the world come to see ʻāhinahina in bloom, when they send up a spectacular flowering spike in mid-summer and then die once they set seed.
ʻĀhinahina were once used in lei making (Prasad and Tomonari-Tuggle 2008). David Douglas wrote in his 1914 journal that on Mauna Kea, the silverswords "were so common that the dry leaves and stems were used as fuel for campfires (Cuddihy and Stone 1990, Douglas 1914)".
Carlquist, S., & Janish, J. R. (1980). Hawaii, a natural history: Geology, climate, native flora and fauna above the shoreline(2nd ed.). Lawai, Kauai: Pacific Tropical Botanical Garden.
Cuddihy, L. W., & Stone, C. P. (1990). Alteration of native Hawaiian vegetation. University of Hawaii Cooperative National Park Study Unit.
Kobayashi, H. K. (1973). Ecology of the silversword, Argyroxiphium sandwicense DC. (Compositae),
Haleakala Crater, Hawaii (PhD dissertation). University of Hawaii, Honolulu.
Krushelnycky PD (2014) Evaluating the Interacting Influences of Pollination, Seed Predation, Invasive Species and Isolation on Reproductive Success in a Threatened Alpine Plant. PLoS ONE 9(2): e88948. https://doi.org/10.1371/journal.pone.0088948
Krushelncyky, P.D., Loope, L., Fortini, L., Felts, J., Drake, D., Starr, F., Starr, K., Giambelluca, T., Brown, M. (2016). Understanding how climate change is affecting Hawaii’s high-elevation ecosystems: an assessment of the long-term viability of Haleakala silverswords and associated biological communities. Pacific Islands Climate Change Center Final Report, Agreement number F12AP00802.
Krushelnycky, P. D., Loope, L. L., Giambelluca, T. W., Starr, F., Starr, K., Drake, D. R., ... & Robichaux, R. H. (2013). Climate‐associated population declines reverse recovery and threaten future of an iconic high‐elevation plant. Global Change Biology, 19(3), 911-922.
Krushelnycky, P.D., W. Haines, L. Loope and E. Van Gelder. 2011. The Haleakala Argentine ant project: a synthesis of past research and prospects for the future. Pacific Cooperative Studies Unit Technical Report 173. University of Hawai‘i at Mānoa, Department of Botany. Honolulu, HI. 127 pp.
Pérez, F. L. (2009). The role of tephra covers on soil moisture conservation at Haleakala's crater (Maui, Hawai'i). Catena, 76(3), 191-205.
Francisco L. Pérez (2014): Spatial aggregation patterns and population
structure of the Haleakalā silversword (Argyroxiphium sandwicense DC. subsp. macrocephalum), Maui, Hawai’i, Physical Geography, DOI: 10.1080/02723646.2014.976466
Prasad and Tomonari-Tuggle 2008 "An Ethnographic Overview and Study of the Cultural Impacts of Commercial Air Tours over Haleakala National Park" 2008, prepared by International Archaeological Research Institute, Inc
Prior to Western contact and the introduction of feral goats, ʻāhinahina “dotted the entire summit area and many of the cinder cones within the crater” (Carlquist 1980). However, numerous threats have reduced the population of this species. Feral goats and pigs, which preferentially eat native plants over non-native plants, decimated ʻāhinahina populations. Additionally, cattle driven through the crater grazed on silverswords. Historically, ʻāhinahina were harvested for lei, floats, pack stock feed, rolled into the crater, and taken home as souvenirs.
Haleakalā National Park was established in 1916 as part of Hawaiʻi National Park to protect and preserve natural and cultural resources, particularly the ʻāhinahina, for the education and enjoyment of future generations. Starting in 1971, Haleakalā National began fencing the summit area of the park and controlling goats. The summit area has been virutually goat-free since the early 1990s, allowing āhinahina and other native vegetation to recover. Feral animal management crews continue to control incursions and maintain fences.
While harvesting silverswords is no longer allowed, off-trail visitor traffic can trample shallow, sensitive ʻāhinahina roots and kill plants (Kobayashi 1973). A strict “Stay on Trail” park policy has largely curbed this threat.
Despite management interventions that have increased silversword populations through protection from feral ungulates and human use, decadal surveys since 1991 have indicated ʻāhinahina population declines, particularly at lower elevations (Krushelnycky et al. 2013). Drought stress due to warmer, drier, less cloud coverage has led to increasing levels of lethal water stress at lower elevations (Krushelnycky et al. 2014).
Applied greenhouse research suggests that plant ecotype is less influential on long-term drought resilience than climatic conditions (Krushelnycky et al., in press). Therefore, choosing higher elevation sites for outplanting and assisted migration will help build climate change-resilient populations of ʻāhinahina.
Students from Iao Intermediate School and Moanalua Intermediate School helped sow ʻāhinahina seeds in the nursery as part of the parkʻs native biodiversity education and outreach programs. They learned about native plants and animals, threats to native ecosystems, and how the park helps protect them. Getting hands-on with ʻāhinahina seeds is a once-in-a-lifetime experience for many urban students who may have little or no contact with native plants.
The Haleakalā Nursery volunteer program meets every first Tuesday of the month. It is open to community members who want to help with nursery tasks and care for native plants, many of which are rare or endangered.
The nursery volunteer program engages about 10 volunteers each month doing various nursery tasks helping to care for native plants (seed cleaning, transplanting, sowing).
As they grow from seedling to full transplant size, ʻĀhinahina need transplanting out of seed flats to bigger pots where they can grow to adequate size in preparation for outplanting. This task can be tedious and time-consuming, but volunteers make it possible to produce enough silverswords for hundreds of students to outplant. The many hands of volunteer workers have transplanted over 2400 ʻāhinahina so far.
Having enough overall size and root mass is critical to ʻāhinahina outplant survival (Krushelnycky 2016). Growing ʻāhinahina in the nursery until they are large enough to outplant helps improve survival rates.
1,348 local students from sixteen public and private schools on Maui planted 2,271 ‘āhinahina in 56 discrete areas below Pu’u-‘ula‘ula. Survival rates of monitored plants averaged to 86%, demonstrating that ʻāhinahina can be successfully restored with community efforts and minimal follow-up by staff.
Volunteers are an indispensable part of the process helping to transplant, weed, and maintain the nursery so that cultivated ʻāhinahina grow to outplant size in a healthy environment.
Through this community-engaging restoration effort informed by science, students are engaged in sowing seeds, learning about biodiversity as a part of their school curriculum, and being a part of the horticultural process. Giving students the opportunity to help reintroduce ‘āhinahina at the Pu’u-‘ula‘ula summit allows them to develop a sense of natural resources stewardship, while restoring cultural, aesthetic, and ecological value and fulfilling the National Park Service (NPS) mission of protecting and preserving natural and cultural resources for future generations.
School group outplantings continue this fall, while nursery volunteer days are ongoing. If you would like to bring your students to outplant ʻāhinahina, or volunteer in the nursery, please contact park horticulturalist Michelle Osgood at email@example.com. This project is building capacity towards the next generation of collaborative resources stewardship at Haleakalā National Park.
Over 1000 Maui students came to Haleakalā National Park over three years (2016-2018) to outplant ʻāhinahina and experience aloha ʻāina work. Students ranged in age from second grade to college, from public and private schools across Maui, primarily targeting the fourth grade cohort of the agency-wide “Every Kid in a Park” campaign.
Outplanting took place over three years (2016-2018) during the wet seasons of fall-winter-spring. Outplanted populations below Puʻu-ʻula-ʻula and along Keoneheʻeheʻe Trail were designed to create high-density, resilient populations that would restore the biocultural landscape of Haleakalā summit. Assisted migration and population bolstering at high elevations for long-term resilience to warmer, drier conditions at lower elevations (Krushelnycky et al., in press). Plants in close proximity are more likely to reproduce successfully, with greater pollination rates and lower seed predation (Krushelnycky 2014).
Park biologists, archaeologists, and rangers gave educational talks on archaeology, wildlife, plants, island ecology, native species, and cultural practices.
A biologist demonstrated outplanting techniques, clearing away the cinder dressing on top, digging a hole for the plant, planting, filling the hole, and re-dressing cinder. Coarse cinder and small stones help retain moisture and regulate temperature (Perez 2012).
Students planted within a designated area to enable follow-up monitoring. The outplant polygon was demarcated in GIS and entered into native plant database.
Plants were watered once right after outplanting, but are xeric afterward.
9 plots with a total of 476 plants were monitored 2-3 years later in 2019. Plots were chosen that didnʻt overlap with other plots and had discernible boundaries (i.e. plants were planted in plots and not too much rogue planting). Plots were outlined with pin flags using GPS polygons and then swept to count plants across entire flagged area.
Mahalo nui to the many park staff and volunteers who assisted with school group outplantings.
Mahalo to the students who helped restore silverswords to Puʻu-ʻula-ʻula.
Finally, mahalo to the innumerable park staff, volunteers, interns, and partners, past and present, who have paved the way for silverswords to recover by building fences, controlling feral animals, pulling weeds, and protecting the natural and cultural resources of Haleakalā National Park.