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Hawaiian High Islands Ecoregion
This page last revised 31 August 2006 -- S.M.Gon III 

Conservation Targets
TNC Action Sites


Maps & Figures
CPT Database
Worlds wettest regionsWet cliffs in the Ko'olau Mountains provide refugia for species of rare plants.

Achatinella, endangered snail. Photo by Bill Mull
The bulk of the species of the endangered genus Achatinella are found in the lowland wet system of the Ko'olau conservation area.

'Apapane on lehua Photo by Jack Jeffrey
Although not a rich forest bird site, the wet forest of the Ko'olauconservation area supports common endemic birds such as this 'apapane (Himatione sanguinea).

Rare loulu palm natural community - Pritchardia martii
The flora of O'ahu boasts a high percentage of island-level endemism. Pritchardia martii is a palm found only in the Ko'olau Mountains.

Ko‘olau Conservation Area Profile

Major Habitat Type: Tropical Moist Forest(Oceania Realm)

Stratification Unit:O‘ahu (comprised of the single island of O‘ahu, see below)The island is noted for a high level of botanical endemism.

Island: O‘ahu; the third largestisland of the archipelago, ca 2.2 million years old, maximum elevation Ka‘ala, Wai‘anae Mountains, 1,220 m(4,003 ft). Bearing two conservation areas: Wai‘anae and Ko‘olau (maximum elevation, Konahuanui, 946 m (3105 ft),corresponding to the two main shield volcanoes that comprise theisland. Most populous island in the archipelago, with >85% of thestate's human population.

Significance: TheKo‘olau Conservation Area  is comprised of lowlandto near-montane ecological systems. The remote summit area maintains viable systems, isa vitallyimportant watershed, comprises headlands for continuous perennial streamcommunities, and provides habitat for nested nativenatural communities and species.  Rich in endemic species of flowering plants.

ConservationStatus: The Ko‘olau Conservation Area is protected and managed by acombination of private and public protected areas, including the O‘ahu Forest National Wildlife Refuge, the State Forest ReserveSystem, and the state Conservation District. These and other lands are in the Ko‘olau Mountains Watershed Partnership. Active conservation management is also underway via the Army's Ecosystem Management Program,involving endangered species and habitat across the Wai‘anae andKo‘olau conservation areas. Such actions are included in adiscussion of conservation strategies for O‘ahu.

A Conservation Action Plan for the Ko‘olau Conservation Area has not yet been drafted.

lowland wet forest above Honolulu
Native Lowland Wet Forest, Wa'ahila Ridge, above Honolulu, O'ahu

Continuous Perennial Stream, Kaluanui Stream, Kaliuwaa Valley
Hawaiian Continuous Perennial Stream, Kaluanui, Ko'olau Mountains

Koolau summit region, O'ahu
Thesummit region of the Ko'olau Mountains is rugged, undeveloped, andnative-dominated. The prevailing ecological system is Lowland Wet.

Conservation Targets:

Ecological Systems:  Two ecological systems of the Ko‘olau Conservation Area  were selected as conservationtargets, each bearing nested natural communities and species (discussedbelow).

System Size Condition LC Overall
  Other systems have POOR overall viability and are not  included.

Natural Communities:

  • Continuous Perennial Stream Community
Selected stream occurrences:O‘ahu bears somehigh quality streams, and the four streams selected: Kaluanui,Kahana, Anahulu, and Punalu‘u Streams are among thelargest and highest quality streams on the island (Hawai‘i StreamAs­ses­s­ment 1991).

Special Ecological Features:

  • Waterbird Concentration
The O‘ahu Waterbird Concentration is defined as five core wetlands and at least ten of 13 wetland sites identified by the USFWSWaterbird Recovery Plan (2005). These include coastal, and riverinesites outside of but adjacent to the ecological system targets of both Ko‘olau and Wai‘anae conservation areas.

Nested Targets:

  • Natural Communities:
‘Ōhi‘a/Uluhe Lowland Wet Forest
Uluhe Lowland Wet Shrubland
‘Ōhi‘a/Mixed Shrub Lowland Wet Forest
Koa/‘Ōhi‘a Lowland Mesic Forest
Mixed Fern/Shrub Wet Cliff Community
Mixed Shrub Dry Cliff Community

  • Native species:

There are manyconstituent native species that comprise the natural communities of the ConservationArea. Highlights include over 40 rare/endangered plant species, over 200 endemicplant species, and an untold number of endemic invertebrate species likelynumbering in the thousands.

Major Threats:Uncontrolledferal ungulates (primarily pigs); and a large variety ofinvasivealien plants, including Christmas berry (Schinus terebinthifolius), alien grasses, Koster's curse (Clidemia hirta), and strawberry guava (Psidium cattelianum). Alien grasses in dry settings contribute to a significant wildfire threat.
Thenative-dominated ecological systems of O‘ahu occupy theupper elevation areas of both Wai‘anae (West) and Ko‘olau(Northeast) mountains,  extending downward into areas (pink)converted into anthropogenic andalien-dominated regions. Ecological systems of the Island of O'ahu
Thenative-dominated ecological systems of O‘ahu  occupy theupper elevation areas of both Wai‘anae (West) and Ko‘olau(Northeast) mountains,  extending downward into areas (pink)converted into anthropogenic andalien-dominated regions. All selected continuous perennial streams flow from the Ko'olau Conservation Area.

Oahu Conservation Areas
Adiagrammatic crosssection of the Island of O‘ahu indicates the variety of moistureand elevation conditions present: a lowland wet summit (Ko‘olauMountains), and mesic to dry systems, with a montane wet cap (Wai‘anaeMountains).  
elevation and moisture settings of O'ahu