Hawaiian Continuous Perennial Streams

Hawaiian High Islands Ecoregion
This page last revised 01 November 2006 -- S.M.Gon III

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Viability of forest bird concentrations were derived from recent assessments by the USGS/BRD.

Rare natural community
Rare plant concentration viability was assessed only for occurrences not nested in ecological systems

Hawaiian streams often are steep, with many falls, riffles, and pools.

Hawaiian Continuous Perennial Streams

The distinctive biotaassociated with Hawaiian streams that run to the sea year-long withoutsignificant diversion or stream channel modifications are known from theislands of Kaua‘i, O‘ahu, Maui, Moloka‘iand Hawai‘i. These streams have basalt basins, generally with bottoms of gravelor boulders, and may range from narrow, steep-sided gorges, to wide,flat-bottomed valleys with alluvial flood plains. The majority of the over 300Hawaiian streams with significant year-long flow have been diverted or alteredto greater or lesser extent in populated areas, so only streams in remotelocalities or those with sparse human populations retain rich native streambiota. Biological information is lacking or limited for about half of thecontinuous perennial streams. This community type is consider azonal or multizonalbecause it may extend across multiple elevation zones (e.g. montane [>1,000m elev] or even subalpine [2,000 m elev] to sea level) and moisture gradientsfrom wet to mesic to dry.

oopu naniha
ʻOʻopu naniha, like other native Hawaiian gobies, requires intact
stream habitat from headwaters to sea. Learn more.

The native biotic componentof Hawaiian streams varies by location, size of stream and extent ofdisturbance. Native stream animals typically include gobiid fish, snails,crustaceans and insects. The five gobiid fish species of Hawaiian continuousperennial streams include 4 endemic species, ‘o‘opu nākea(Awaous stamineus), ‘o‘opu nopili (Sicyopterisstimpsoni), ‘o‘opu alamo‘oor ‘o‘opuhi‘ukole(Lentipes concolor) and ‘o‘opu okuhe or akupa(Eleotris sandwicensis), and one indigenous species, ‘o‘opunaniha (Stenogobius genivitatus), known also from Samoa. Other nativefish found in Hawaiian streams include aholehole (Kuhlia sandvicensis)and mullet (Mugil cephalus).

Continuous Perennial Stream, East Maui
Hawaiian Continuous Perennial Stream, Hanawī, East Maui
Learn more at the State of Hawai'i Aquatic Resources page.

Two endemic decapods comprise the nativemacro-crustacean fauna, the shrimp ‘ōpae kala‘ole(Atyoida bisulcata) and the prawn ‘ōpae‘oeha‘a(Macrobrachium grandimanus). Several macro-mollusks are inhabitants ofHawaiian streams,. including hīhīwai, or wī(Neritina granosa), brown wī or hapawai (Theodoxus vespertinus)and several species of Melanoides. There are in addition, severalspecies of smaller native crustaceans, mollusks and insects in Hawaiianstreams. Nearly all of the stream-related Hawaiian fishes, macro-crustaceansand macro-mollusks require oceanic larval development, followed by upstreammigration and maturation.

Threats

Threats toHawaiiancontinuous perennial streams include modifications of channel, changesinstream flow by diversion of water, siltation via erosion of disturbedwatersheds, direct or indirect pollution of surface or groundwater, andintroduction of alien stream animals that either feed on or competewith nativespecies. Because of the diadromous life cycles of most nativestream macrofauna, intact headwaters and upper stream courses withhighly modified lower courses and mouths limit all but the most hardynative species.

Even the most remote and unaltered streams may be invaded by alienspecies, if those species have oceanic larvae that can disperse between streamsor between islands. Alien prawns, such as the Tahitian prawn (Macrobrachiumlar) and Malaysian prawn (M. rosenbergii) are predatory on almostall native stream elements, have an oceanic dispersal phase, and are aparticularly difficult problem to address. Other significant alien streamanimals include fishes such as cichlids (Cichlasoma spp.), catfish (Clariasfuscus), bass (Micropterus spp.), tilapia (Tilapia spp.),live-bearers, such as mosquitofish (Gambusia affinis), guppies (Poeciliaspp.), and swordtails (Xiphophorus, spp.) and the freshwater clam (Corbiculeafluminea)

Protected examples ofHawaiian continuous streams may be found in the Waimanu Estuarine Sanctuary, PelekunuPreserve of The Nature Conservancy of Hawai‘i, KīpahuluValley in the Haleakalā National Park and WaiahuakuaValley in the Hono O Nā Pali Natural Area Reserve.

hihiwai and opae kalaole

Two native stream macroinvertebrates: the nerite snail hīhīwai (Neritina granosa) left, and the atyid shrimp 'ōpae kala'ole (Atyoida bisulcata).

Streams of the Ecoregional Portfolio

Twenty viable examples of streams (foureach on five stream-bearing islands) were selected for the ecoregionportfolio. The stream and surrounding watershed, from source to ocean,comprise the stream conservation area. These overlap with uplandecological systems, but typicaly extend into lower elevationalien-dominated areas. Click on the items in the list below to viewstream locations.

KAUA‘I
Hanakāpī‘ai
Limahuli
Lumaha‘i
Waimea

O‘AHU
Anahulu
Punalu‘u
Kaluanui
Kahana

MOLOKA‘I
Waikolu
Pelekunu
Wailau
Hālawa

MAUI
Honokōhau
Kahakuloa
Hanawī
‘Ohe‘o

HAWAI‘I
Waipi‘o
Honokānenui
Honoli‘i
Hanawī

PortfolioStreams of the Hawaiian High Islands Ecoregion are to be found on thefive largest islands of Hawai'i, Maui, Moloka'i, O'ahu, and Kaua'i.Only these larger islands have watersheds and aquifers sufficient tomaintain continuous perennial stream flow. The portfolio maps at rightdepict the tributary networks of these portfolio streams, whichtypically drain major portions of the native dominated ecologicalsystems. An attempt was made to stratify stream selection acrossportfolio conservation areas.

Selected portfoliostreams for Maui Island occur in two conservation areas: West Maui(Honokōhau & Kahakuloa Streams), and East Maui (Hanawī and 'Ohe'o Streams)

Streams of Moloka'i

Selectedportfoliostreams for Moloka'i Island are Waikolu, Wailau, Pelekunu, andHālawa. Wailau and Pelekunu are considered among the highestquality streams inthe ecoregion.

Selected streams of Kaua'i

Selectedportfoliostreams for Kaua'i Island are Hanakāpī'ai, Limahuli, Lumaha'i, andWaimea. The Waimea drainage in particular is one of the most complex inthe ecoregion.

Selectedportfolio streams for Hawai‘i Island occur in twoconservation areas: Kohala (Waipi‘o & Honokanenui Streams),and Mauna Kea (Honoli‘i & Hanawī Streams)

Selected streams of O'ahu

Selected portfoliostreams for O'ahu Island are Kaluanui, Punalu'u, Kahana, and Anahulu. All four drain from the wet Ko'olau conservation area.