Effects of Extreme Drought on Vegetation of a Lava Flow on Mauna Loa, Hawai'i

Abstract

Effects of an extreme drought were examined along an elevational gradient on Mauna Loa Volcano, Hawai'i. The composition, vigor, and survivorship of plants were examined on a 2400-yr-old pahoehoe lava flow at three elevations: 1755,2000, and 2195 m above sea level. Three plant species, Coprosma ernodeoides A. Gray, Styphelia tameiameiae (Cham. & ScWechtend.) F. v. Muell., and Vaccinium reticulatum Sm., were encountered most frequently at the three sites. Greatest mortality occurred at the site at 2000 m elevation, where the drought caused a shift from a slight excess of precipitation over evaporation to a large excess of evaporation. Occasional severe droughts may play an important part in shaping primary succession in this region.