This page last revised 21 July 2007
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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.
The Hawaiian High Islands Ecoregion is marked by a very wide range of local physiographic settings. These include fresh massive volcanic shields and cinderlands reaching over 4000 m (13,000 ft) elevation; eroded, faceted topo- graphies on older islands; high sea cliffs (ca 900 m [3,000 ft] in height); raised coral plains; and amphitheater-headed valley/ridge systems with alluvial/colluvial bottoms. Numerous freshwater stream systems are found primarily 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, but with combinations of elevation and orographic rainfall patterns that yield extremely wet (>1000 cm [>400 inches] annual rainfall) to extremely dry (<25cm [<10 inches] annual rainfall) settings within a short distance of each other (<40 km [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 montane elevations (>1000 m [>3000 ft]). The general patterns of climatic variation found on the largest of the
The Hawaiian High Islands Ecoregion (right, yellow oval) lies within the Hawaiian Province (red oval), in the Oceanian Biogeographic Realm.
High island orographic climate results in both extremes of wet and dry, while broad elevational 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 native
terrestrial invertebrates) (Loope 1999). An estimated 15,000 endemic species occur in the ecoregion (Eldredge & Evenhuis 2003). The
of about 1,200 vascular plant species is disharmonic, that is, lacking
many genera and families that typically mark tropical island systems (Sohmer & Gon 1995). Rare and endangered taxa, including
endangered plants, forest birds, and land snails comprise >25% of the fauna. Hawai‘i
includes more endangered species than any other state in the
In addition to species, all but a handful of the approximately 150 described terrestrial native natural communities are endemic. Vegetation includes grasslands, shrublands, woodlands, and forests in lowland, submontane, montane, subalpine, and alpine settings (Pratt & Gon 1998). Hawai‘i supports more Holdridge life form categories than any other ecoregion known (Tosi et al 2001, 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-level endemics, fewer than half the flowering plant taxa (409) show multi-island distributions. Fewer than 150 can be found on all six of the higher main islands. The situation is even more pronounced among invertebrates, which comprise the majority of species-level diversity, and show remarkable diversification and geographic endemism even within a single island setting.
Multiple examples of ecological systems across the archipelago are clearly required to adequately represent species level biological 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 ecosystems in Hawai‘i
Strong connections between the natural world and indigenous Hawaiian culture can aid conservation.
Land Use Patterns
Human residence and extractive land uses are largely concentrated below 600 m (2000 feet) elevation. Land uses include high-density urban, residential, agricultural, grazing, and lands dedicated to military training. Higher elevation areas are more natural, are largely zoned for conservation, and include many areas in protective status such as national parks, natural area reserves, forest reserves, preserves, and refuges. Upland watersheds on most of the main islands are included in informal public-private cooperative management areas called watershed partnerships, managed for maintenance and management of forested watershed. Over 30% of the ecoregion is privately-owned, 29% in state holdings, approximately 8% in federal lands, and the remainder in county and other tenure. These proportions also apply to the biologically intact island interiors, necessitating state, federal, and private participation in comprehensive conservation efforts (Hawai‘i GAP 2005).The consequences of past land use practices can be 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 is
none of the sometimes violent instability that plagues many tropical
tracts of former agricultural lands are being converted into residential areas
or are left fallow, often creating vectors for weed invasions or wildfire. Rapidly
rising land and property costs (among the highest in the U.S.) have
created a high cost of living, exacerbated by our geographic isolation and need
to import many/most necessities (food, shelter, clothing, fuel). Economically
depressed rural areas occur on all islands where subsistence hunting/fishing
persists. Business centers can be found in
Socio-economic impacts on natural systems can be seen in urban and suburban sprawl that impinges on the boundaries of the Conservation District, continued deforestation in agriculturally-zoned lands on the Island of Hawai‘i in the Kona District, and damage inflicted by military training exercises in and adjacent to native ecological systems (especially on O‘ahu and Hawai‘i islands). Hawai‘i has largely effective land use zoning, establishing a Conservation District that corresponds well to the remaining native-dominated areas (with some notable exceptions).
Government agencies and the public recognize that natural areas and watersheds are important for quality of life. Strong connections between the natural world and indigenous Hawaiian culture hold great potential for conservation. However, conservation and public land management are severely under funded and a multiple use mandate conflicts with management actions focused on biodiversity conservation. High land costs make acquisition a very expensive strategy, and overall high costs of living apply to the costs of essential management actions.