Our Liviiii^ Resources — HciM'aii 



JOS 



a review). To gain more inrormation about 

 Hawaii's resources, the state legislature Ibrmed 

 the Hawaii Biological Survey in 1992, whose 

 mission and scope are described in this section 

 (Allison et al.). 



References 



Ciilliney. J-L. lySS. islands in a far sea. Sierra Cluh Bonks. 

 San Franeisco. CA. 410 pp. 



Gagne, W.C. 1988. Conservation priorities in Hawanan nat- 

 ural systems. BioScience .^8(4 1:264-271. 

 Olson. S.L.. and H.F. James. 1901. Deseriptions ol thirty- 

 two new speeies of birds from the Hawaiian Islands; Part 



I. Non-passeriformes. Ornithological Monographs 4.'i;l- 



88. 

 Seott, J.M., C.B. Kepler. C. vanRipei, and S.l. Fefer 1988. 



Conservation of Hawaii's vanishing avifauna. BioScience 



-^8 (4):238-25.\ 

 Scotl. J.M., S. Mountainspring. F.L. Ram.sey. and C.B. 



Kepler. 1986. Forest bird communities of the Hawaiian 



Islands: their dynamics, ecology and conservation. Studies 



in Avian Biology 9. 431 pp. 

 Stone. C.P.. C.W.'^Smith. and J.T. Tunison. 1992. Alien plant 



invasions in native ecosystems of Hawaii management and 



research. University of Hawaii Press. Honolulu. 887 pp. 

 Stone. C.P.. and J.M. Scott, eds. 1985. Hawaii's terrestrial 



ecosystems: preservation and management. University of 



Hawaii Press. HI. 584 pp. 



The Haleakala silversword (Argymxiphiwu 

 samhriceuse ssp. macwcephalum) was near 

 extinction in the I920"s because of human van- 

 dalism and browsing by goats and cattle. The 

 plant has increased under protection and 

 deserves attention as the most dramatic conser- 

 vation success story of the Hawaiian Islands. 



The silversword is a distinctive, 

 globe-shaped rosette plant with rigid (sword- 

 like), succulent leaves densely covered by silver 

 hairs. When a plant flowers at the end of its life, 

 it produces a spectacular flowering stalk 

 0.5-2.0 m (1.6-6.4 ft) tall, typically with hun- 

 dreds of maroon sunflowerlike flower heads. 

 This plant receives more attention from visitors 

 to Haleakala National Park than any other plant 

 or animal because of its striking appearance and 

 restricted distribution. 



The Haleakala silversword is endemic to a 

 I.OOO-ha (2,471-acre) area at 2.100- to 3.000-m 

 (6.890- to 9,843-ft) elevation in the crater and 

 outer slopes of Haleakala "Volcano, within 

 Haleakala National Park. Maui. Hawaii. It is the 

 most famous member of the endemic Hawaiian 

 silversword alliance, perhaps the premier exam- 

 ple of evolutionary adaptive radiation in plants. 

 This moiphologically diverse group comprises 

 28 species of herbs, vines, shrubs, trees, and 

 rosette plants in three genera that evolved in the 

 Hawaiian Islands from a North American tar- 

 weed (Asteraceae: Madiinae) ancestor 

 (Robichaux et al. 1990; Baldwin et al. 1991). 

 The monocaipic (flowers only once, at the end 

 of its lifetime) silversword matures from seed to 

 its final flowering stage in about 15-50 years. 

 The plant remains a compact rosette until it 

 sends up an erect, central flowering stalk, sets 

 seed, and dies. 



In 1992 this taxon was given threatened sta- 

 tus by the U.S. Fish and Wildlife Service 

 because of its extremely limited range and pre- 

 carious life cycle. The other subspecies of A. 

 sandwicense (ssp. sandwicense). endemic to 

 Mauna Kea on the island of Hawaii, is federal- 

 ly listed as endangered, with fewer than 100 

 naturally occurring individuals. 



Population Trends 



The strikingly beautiful Haleakala silver- 

 sword has always aroused the curiosity of 

 human visitors to Haleakala Volcano. In 

 pre-park days, plants were often removed by 

 travelers to Haleakala "Volcano as proof that the 

 party had reached the summit, a practice that 

 eventually seriously affected the silversword 

 population. Browsing by feral goats and domes- 

 tic cattle was also a significant factor in the sil- 

 versword decline, but it was not a species pre- 

 ferred by these animals. By the 1920's, silver- 

 sword numbers were so depleted that the Maui 

 Chamber of Commerce sent a petition to 

 Washington. DC, requesting that a serious effort 

 be made to save the species (Loope and 

 Crivellone 1986). 



The first reliable quantitative information on 

 silversword numbers is from the summer of 

 1935. In that year. Ranger S.H. Lamb tallied 

 1.470 plants (88 of which were flowering) on a 

 single cinder cone (Ka Moa o Pele) within 

 Haleakala Crater (Lamb 1935). Because about 

 217 plants were flowering within the crater at 

 that time (Lamb 1935). a reasonable estimate of 

 the total population is about 4,000 individuals. 



Because silversword plants occur on other- 

 wise banen cinder, fairly accurate counts are 

 possible. Two studies since 1935 illustrate the 

 trend of the silversword population over about 

 60 years of protection. Methods are described in 

 the original reports (Kobayashi 1973, 1993; 

 Loope and Crivellone 1986). 



On Ka Moa o Pele, a single cinder cone 

 where the largest number of plants were in 

 1935. the silversword population had increased 

 from 1.470 to 6,528 plants as of 1991 (Fig. I). 



Elsewhere in Haleakala Crater, the silver- 

 sword has increased in numbers and extent, 

 large local populations having developed in 

 areas where few plants occurred in 1935. A cen- 

 sus of the entire silversword population has been 

 attempted four times since 1971, with the fol- 

 lowing results: 1971: 43,262 (Kobayashi 1973); 

 1979-80: 35,000 (Kobayashi 1993); 1982: 

 47,640 (Loope and Crivellone 1986); and 1991: 



Haleakala 

 Silversword 



by 



Lloyd L. Loope 



Arthur C. Medeiros 



National Biological Service 



Haleakala silversword 

 {Argyroxiphium sandwicense ssp. 

 macrocephalum). 



