Hibiscus arnottianus A.Gray

Taxonomic Classification

Hibiscus arnottianus is a species of flowering plant in the mallow family, Malvaceae.

Growth Form and Native Range

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.

General Threat Overview

This species is currently threatened by competition from invasive non-native plants, as well as predation and habitat degradation caused by introduced animals.

Impact of Invasive Plants

Invasive non-native plants change the species' native habitat and compete with it for space, light, moisture, and nutrients.

Threats from Ungulate Introductions

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.

Threats from Invertebrate and Rodent Introductions

Introduced black rats (Rattus rattus) and introduced slugs and snails feed on the plant's parts and fruits.

Environmental Threats

The species is also threatened by landslides, fire, and drought, all of which are made more severe by existing habitat degradation.

IUCN Global Conservation Status

Hibiscus arnottianus is listed as Endangered on the IUCN Red List.

Subspecies Count

Three subspecies are currently accepted.

Subspecies arnottianus Distribution

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.

Subspecies arnottianus Conservation Status

This subspecies is assessed as Endangered by the IUCN.

Subspecies immaculatus Distribution

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.

Subspecies immaculatus Conservation Status

This subspecies is assessed as Critically Endangered by the IUCN.

Subspecies punaluuensis Distribution

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.

Subspecies punaluuensis Conservation Status

This subspecies is assessed as Endangered by the IUCN.