The Hawaiian Islands as a Model System for Ecosystem Studies

Abstract

The Hawaiian Islands encompass an extraordinary range of variation in climate and soil age in a small area; the younger volcanoes are also extraordinary for their lack of variation in relief or topography, parent material, and biota (before widespread invasions by alien species). Consequently, in Hawai'i the independent and interactive effects of temperature, precipitation, and soil age on ecosystem structure and function can be evaluated with a power that is beyond the reach of studies elsewhere. Not only are extreme conditions well represented in Hawai'i, but there are also complete gradients between the extremes, allowing the determination of the relationships as well as the differences among sites. My colleagues and I have established two sets of sites that make use of these gradients: the Mauna Loa Environmental Matrix, a set of lava flows ('a'a versus pahoehoe, old versus young) that cover a broad elevational range on the wet east versus dry northwest flank of Mauna Loa; and a chronosequence of sites that reaches from Kilauea (~300 yr old) to Kaua'i (~4,100,000yr old) at 1200 m elevation, 2500 mm annual precipitation. These sites are being used to determine climatic and developmental controls of ecosystem function. I report some of the early results here.