POTENTIAL NITROGEN-FIXATION DURING PRIMARY SUCCESSION IN HAWAII VOLCANOS NATIONAL-PARK

I determined rates of acetylene reduction and estimated rates of nitrogen fixation in three sites that varied in soil age and nitrogen accumulation on Kilauea Volcano, Hawai'i. The major substrates in which acetylene reduction occurred were lichens of the genus Stereocaulon, liverworts, decaying leaf litter, and decaying wood. Estimated rates of nitrogen fixation were 0.3, 1.2, and 2.8 kg.ha-1.yr-1 in an open-canopied 27 yr old site, a 200 yr old primary successional montane rain forest, and an approximately 2000 yr old montane rain forest, respectively. The sum of nitrogen fixed by these sources plus nitrogen inputs in precipitation was insufficient to explain the quantity of nitrogen accumulated in the 200 yr old site.