Native to Hawaii, silversword (Argyroxiphium sandwicense ssp. sandwicense) was a dominant plant of alpine and subalpine regions until the 1700s. At that time, Europeans introduced sheep and other nonnative animals to the islands.
Overtime, the number of sheep dramatically increased and silversword populations decreased. There are currently only 42 plants left on Mauna Kea, a volcano on the island of Hawaii. Researchers believe silversword declined due to over grazing. The remaining plants grow on steep cliffs and rock faces that cannot be reach by grazing animals.
Robichaux R, Bergfeld S, Bruegmann M, Canfield J, Moriyasu P, Rubenstein T, Tunison T, Warshauer F. 2000. Reintroducing Hawaii’s Silverswords. <http://www.fws.gov/endangered/bulletin/2000/05-06/22-23.pdf>. Accessed 2006 Aug 27.