One of the highlights of Maui is undoubtedly the Haleakala volcano — a massive uprising of lava that forms about 75% of the island.
Its peak rises to over 10,000 feet but is a huge depression crater 7 miles long, 2 miles wide, and 2600 feet deep. The last eruption was probably sometime in the 17th century, making it safe to explore. The landscape atop this volcano is stark, with chunks of broken lava interspersed with fine gravel.
Only the hardiest of plants can survive the altitude, cold temperatures, and arid environment here. One of those survivors is the Maui Silversword, a strange looking member of the daisy family that grows a circular rosette of sword-shaped leaves for up to 90 years before sending forth its one stalk of 500 or more flowers.
Spear-shaped leaves retard water loss and deflect the sun’s radiation. Tiny hairs that cover the leaves’ surface hold heat and moisture, effectively raising the temperature above freezing during cold nights and morning.
The Silversword once covered the slopes of the volcano so thickly that the mountain looked like it had a coating of glittering snow, formed by the silvery leaves of the dried plants. But over-grazing by livestock, trampling on the fine network of superficial roots, and harvesting by humans depleted this endemic Maui plant almost to the point of extinction.
This is the story of many of Maui’s endemic fauna and flora. Although Hawaii makes up only 0.2% of the U.S. land mass, its endangered species comprise 25% of those on the U.S. list. Most of these species share the fate of the Maui Silversword — competition from introduced invasive species, habitat destruction or alteration, lack of resistance to introduced diseases (e.g., avian malaria), and now — threatened by climate change as the mid- and higher altitudes at which endemic animals and plants could escape the competition or disease warms up to allow survival of the invaders.