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This page last revised 21 July 2007
TNC Action Sites
Maps & Figures
Remarkable physiographic and climatic diversity marks the ecoregion.
Some of the world's wettest regions lie in the ecoregion's montane systems
The Hawaiian ecoregion contains highly diverse physiography.
TheHawaiian High Islands Ecoregion is marked by a very wide range of localphysiographic settings. These include fresh massive volcanic shields andcinderlands reaching over 4000 m (13,000 ft) elevation; eroded, facetedtopo- graphies on older islands; high sea cliffs (ca 900 m [3,000 ft] in height);raised coral plains; and amphitheater-headed valley/ridge systems withalluvial/colluvial bottoms. Numerous freshwater stream systems are foundprimarily on the older, eroded islands, but also on the wet, windward slopes of even the youngest island, Hawai‘i (Juvik & Juvik 1998).
ClimateThe general climate is tropical/subtropical, butwith combinations of elevation and orographic rainfall patterns that yield extremelywet (>1000 cm [>400 inches] annual rainfall) to extremely dry (<25cm [<10inches] annual rainfall) settings within a short distance of each other (<40km [25 miles]), topped by alpine deserts on the youngest and highest islands(Giambelluca & Schroeder 1998).All but two of the eight main Hawaiian Islands rise to montaneelevations (>1000 m [>3000 ft]). The general patterns of climaticvariationfound on the largest of the
The Hawaiian High Islands Ecoregion (right, yellow oval) lies withinthe Hawaiian Province (red oval), in the Oceanian BiogeographicRealm.
High islandorographic climate results in both extremes of wet and dry, while broadelevational reach yields tropical hot to alpine temperature regimes.(Click on the image above to view a larger version).
Hawai‘i boasts the highest overall species and ecosystem endemism of any ecoregion.
Hawai‘i includes more endangered species than any other state of the U.S.
The Hawaiian High Islands Ecoregion is marked by extremely high endemism (e.g.,~90% endemism of native flowering plants; >98% endemism of nativeterrestrial invertebrates) (Loope 1999). An estimated 15,000 endemic species occur in the ecoregion (Eldredge & Evenhuis 2003). TheHawaiian floraof about 1,200 vascular plant species is disharmonic, that is, lackingmany genera and families that typically mark tropical island systems (Sohmer & Gon 1995). Rare and endangered taxa, includingendangered plants, forest birds, and land snails comprise >25% of the fauna. Hawai‘iincludes more endangered species than any other state in the
In addition to species, all but ahandful of the approximately 150 described terrestrial native naturalcommunities are endemic. Vegetation includes grasslands, shrublands, woodlands,and forests in lowland, submontane, montane, subalpine, and alpine settings(Pratt & Gon 1998). Hawai‘i supportsmore Holdridge life form categories than any other ecoregion known (Tosi et al2001, Ewell 2004). Lists of the natural communities and rare/endangered species of the ecoregion can be found in the appendices.
Biological diversity in the
Because of all of these island-levelendemics, fewer than half the flowering plant taxa (409) showmulti-island distributions. Fewer than 150 can be foundon allsix of thehigher main islands. The situation is even more pronounced amonginvertebrates,which comprise the majority of species-level diversity, and showremarkablediversification and geographic endemism even within a singleisland setting.
Multiple examples of ecological systems acrossthe archipelago are clearly required to adequately represent species levelbiological diversity. For broad-scale planning, a geographic stratification approach is needed, and was developed as part of this 2nd interation plan.
Alien species, such as feral ungulates, are a prevailing threat to native ecosystemsin Hawai‘i
Strong connections between the natural world and indigenous Hawaiian culture can aid conservation.
Land Use Patterns
Humanresidence and extractive land uses are largely concentrated below 600 m(2000feet) elevation. Land uses include high-density urban, residential,agricultural, grazing, and lands dedicated to military training. Higherelevation areas are more natural, are largely zoned for conservation,andinclude many areas in protective status such as national parks, naturalareareserves, forest reserves, preserves, and refuges. Upland watersheds onmost ofthe main islands are included in informal public-private cooperativemanagementareas called watershed partnerships, managed for maintenance andmanagement offorested watershed. Over 30% of the ecoregion is privately-owned, 29%in state holdings,approximately 8% in federal lands, and the remainder in county andother tenure. These proportions also apply to the biologically intactislandinteriors, necessitating state, federal, and private participation incomprehensive conservation efforts (Hawai‘i GAP 2005).The consequences of past land use practices canbe seen on
Remaining native-dominated regions on the Island of Maui (discussion above)
Continue to Ecoregional Conservation Targets
The general setting for conservation in Hawai‘i is relatively stable. There isnone of the sometimes violent instability that plagues many tropicalbiodiversity hotspots.
Largetracts of former agricultural lands are being converted into residential areasor are left fallow, often creating vectors for weed invasions or wildfire. Rapidlyrising land and property costs (among the highest in the U.S.) havecreated a high cost of living, exacerbated by our geographic isolation and needto import many/most necessities (food, shelter, clothing, fuel). Economicallydepressed rural areas occur on all islands where subsistence hunting/fishingpersists. Business centers can be found in
Socio-economicimpacts on natural systems can be seen in urban and suburban sprawl thatimpinges on the boundaries of the Conservation District, continueddeforestation in agriculturally-zoned lands on the Island of Hawai‘i in theKona District, and damage inflicted by military training exercises in andadjacent to native ecological systems (especially on O‘ahu and Hawai‘iislands). Hawai‘i has largely effective land use zoning,establishing a Conservation District that corresponds well to the remainingnative-dominated areas (with some notable exceptions).
Government agencies and the public recognize that natural areas and watershedsare important for quality of life. Strong connections between the natural world and indigenous Hawaiian culturehold great potential for conservation. However, conservation andpublic land management areseverely under funded and a multiple use mandate conflictswith management actions focused on biodiversity conservation. Highlandcosts make acquisition a very expensive strategy, and overall highcosts ofliving apply to the costs of essential management actions.