Populations of exotic earthworms responded positively to the presence of the nitrogen-fixing tree, Myrica faya, which is currently invading early succesional habitats in Hawaii Volcanoes National Park. Earthworm biomass in one high-density stand of Myrica was over three times the levels in nearby submontane forest and rainforest. Comparisons of earthworm populations under pairs of Myrica and the dominant native tree, Metrosideros polymorpha, showed biomass levels to be elevated from over two- to almost eightfold under the exotic tree. The increased rate of burial of nitrogenrich litter by earthworms can alter the rate of nitrogen accretion and cycling in these ecosystems.
Keywords: Biological invasion; Earthworms; Hawai'i; Nitrogen dynamics.