About Hibiscus arnottianus A.Gray
Hibiscus arnottianus is a species of flowering plant in the mallow family, Malvaceae. It grows as a shrub or small tree, and is native to the Hawaiian islands of Oahu and Molokai, where it occurs in tropical rainforest. This species is currently threatened by competition from invasive non-native plants, as well as predation and habitat degradation caused by introduced animals. Invasive non-native plants change the species' native habitat and compete with it for space, light, moisture, and nutrients. Feral pigs (Sus domesticus), goats (Capra hircus), and axis deer (Axis axis) damage individual Hibiscus arnottianus plants and degrade the species' habitat through excessive browsing, trampling, and rooting for food. Introduced black rats (Rattus rattus) and introduced slugs and snails feed on the plant's parts and fruits. The species is also threatened by landslides, fire, and drought, all of which are made more severe by existing habitat degradation. Hibiscus arnottianus is listed as Endangered on the IUCN Red List. Three subspecies are currently accepted. Hibiscus arnottianus subsp. arnottianus, with the synonym Hibiscus boryanus Hook. & Arn., is native to the Waiʻanae Range of Oahu, at elevations between 120 and 790 meters. This subspecies is assessed as Endangered by the IUCN. Hibiscus arnottianus subsp. immaculatus (M.J.Roe) D.M.Bates, with the synonym Hibiscus immaculatus M.J.Roe, is native to eastern Molokai, including the Waihanau and Papalaua valleys, at elevations between 300 and 800 meters. This subspecies is assessed as Critically Endangered by the IUCN. Hibiscus arnottianus subsp. punaluuensis (Skottsb.) D.M.Bates, with the synonym Hibiscus punaluuensis (Skottsb.) O.Deg. & I.Deg., is native to the Koolau Range of eastern Oahu, at elevations between 120 and 790 meters. This subspecies is assessed as Endangered by the IUCN.
