tnc logo
Hawaiian High Islands Ecoregion
This page last revised 11 May 2009 -- S. Falzarano
Conservation Targets
TNC Action Sites


Maps & Figures
CPT Database
hala, Hawaiian screwpine
Hala, a native coastal tree, can dominate
in mesic portions of the coastal system.

moli at kaena
Seabird nesting colonies can occur in
coastal vegetation areas

‘Ena‘ena (Pseudognaphalium sandwicensium) is a coastal aster clothed in dense white felt.

Coastal Vegetation

Native coastal vegetation in the Hawaiian High Islands Ecoregion occupies a relatively narrow zone extending above the influence of waves, typically within 100 m inland, but sometimes extended further when strong prevailing onshore winds drive coastal influence such as sea spray and sand dunes into the lowland zone. Although coastal settings are typically dry, on windward shores rainfall may be high enough to support mesic and even wet vegetation, and riparian conditions adjacent to stream mouths may also be locally  mesic to wet.  This coastal ecosystem is found on all of the main islands of Hawai‘i, Maui, Moloka‘i, Lāna‘i, Kaho‘olawe, O‘ahu,  Kaua‘i, and Ni‘ihau, with best current development along the least populated, rugged, and remote coastlines on Hawai‘i, Maui, Moloka‘i, Kaho‘olawe, O‘ahu, and Kaua‘i. For example, the dune systems at Mo‘omomi (West Moloka‘i) and Ka‘ena Point (O‘ahu) have been described as among the most intact remaining in the main Hawaiian Islands.

ohai flower
Many plants of the coastal system, such as this endemic dwarf shrub ‘ōhai (Sesbania tomentosa) are rare and endangered, threatened by loss of habitat, insect pests,  feral ungulates, and invasive weeds. Image courtesy of Kim & Forest Starr, HEAR website.
loulu coastal forest
The Coastal System in Hawai‘i includes a variety of grasslands, shrublands and forests,such as this loulu palm forest on the top of Huelo Rock.

Relative to the other ecological systems of the ecoregion, the remnants of coastal vegetation are typically isolated and not contiguous with the remaining lowland systems. In prehuman times, there would have been a transition between the coastal vegetation and the adjacent lowland systems, differing in both composition and structure. Coastal vegetation is typically both salt-tolerant and affected by frequent wave disturbance. There are a number of natural communities described within this system, including a variety of grasslands, shrublands, and a few forests. Biological diversity is low to moderate in this system, but some specialized plants and animals occur there, such as nesting seabirds and the rare Hawaiian shrub, ‘ōhai (Sesbania tomentosa spp.)

coastal veg at Kapapa
More typically, coastal vegetation  is low-statured, and tolerant of harsh, seaside conditions., such as this windblown strand at  Kapapa, O‘ahu.

Natural communities and species of this system are listed among nested targets via the appendices.

The distribution of the Coastal System across the Hawaiian High Islands Ecoregion is depicted below in red with native ecosystems in green.

Coastal Vegetation on O'ahu
The Coastal System on O'ahu has been largely displaced by development except along the least populated coastlines.

Coastal Vegetation on Kaua'i
The Coastal System on Kaua'i still occurs along the roadless northwestern coast and along less frequented shorelines.

Coastal Vegetation on  Moloka'i
The Coastal System on Moloka'i has been reduced by human disturbance, weeds, and feral ungulates to the more remote and rugged northern shoreline, and portions of the west coast.

Coastal Vegetation on Ni'ihau
The Coastal System near Ni'ihau occures only on Lehua islet (north) and Kaula Rock (south).

Coastal Vegetation on Kaho'olawe
The Coastal System on Kaho'olawe 
Coastal Vegetation on Hawai'i
The Coastal System on Hawai‘i Island occurs along several more remote coastlines of the island.

Coastal Vegetation on Maui
The Coastal System on Maui is very fragmented except for the remote north coast of West Maui.

Coastal Vegetation on Lana'i
The Coastal System on Lāna'i is heavily fragmented, and has been degraded by feral ungulates and weed invasions.

Statewide Coastal Vegetation
Statewide, the Coastal System

lehua blossom