Invasive species in Hawaii and health-related problems. The introduction of mosquitoes to Hawaii has resulted in the spread of avian malaria, and increases the risk of dengue and west Nile virus (not known to be in Hawaii yet). Other native species can be affected by invasive species diseases as well, such as the once-dominant koa tree being killed by koa wilt, which is believed to have been brought into Hawaii on an ornamental acacia plant, and the 'ohi'a tree, now being affected by Rapid Ohia Death. Invasive predators can severely reduce the population sizes of native species, or even drive them extinct, because native
Hawaiian tropical dry forests Hawaiian tropical dry forests The Hawaiian tropical dry forests are a tropical dry broadleaf forest ecoregion in the Hawaiian Islands. They cover an area of on the leeward side of the main islands and the summits of Niihau and Kahoolawe. These forests are either seasonal or sclerophyllous. Annual rainfall is less than and may be as low as ; the rainy season lasts from November to March. Dominant tree species include koa ("Acacia koa"), koaia ("A. koaia"), akoko ("Euphorbia" spp.), ōhia lehua ("Metrosideros polymorpha"), lonomea ("Sapindus oahuensis"), māmane ("Sophora chrysophylla"), loulu ("Pritchardia" spp.), lama ("Diospyros sandwicensis"), olopua ("Nestegis sandwicensis"), wiliwili