There are various natural community designations and hierarchies that have been used for Hawaiian natural communities. At the end of a hierarchy is a set of detailed natural communities that are typically described by the dominant flora so that designation of natural communities and vegetation types used in Hawaiʻi are the same in some of the descriptive systems used. Overall, as seen in the descriptions below, there are somewhat confusing sets of natural community designations and the status of at least some of those communities does not seem clear.
The Nature Conservancy has defined a Hawaiʻi High Ecoregion System that contains three major habitat types: Tropical Moist Broadleaf Forest, Tropical Dry Broadleaf Forest, and Tropical Grasslands, Savannas & Shrublands: http://www.hawaiiecoregionplan.info/MHT.html. The website states ‘These are based on the World Wildlife Fund (WWF) four ecoregions for the Hawaiian Islands (Hawai‘i Tropical Moist Forest [OC0106], Hawai‘i Tropical Dry Forest [OC0202], Hawai‘i Tropical High Shrubland [OC0701], and Hawai‘i Tropical Lowland Shrubland [OC0702]) (Gon & Olson 1999, Ricketts et al 1998) in which the last two shrubland types are combined into a single MHT (Tropical Grasslands, Savannas & Shrublands) while the moist and dry forest WWF ecoregions represent the other two MHTs (Tropical Moist Broadleaf Forest and Tropical Dry Broadleaf Forest).’
The following link is a quick map view of where these areas are located on the islands: http://bioimages.vanderbilt.edu/ecoregions/70701frame.htm. Better links and some additional information on these major habitat types are here: https://en.wikipedia.org/wiki/Hawaiian_tropical_rainforests
The Nature Conservancy (http://www.hawaiiecoregionplan.info/home.html) refers to and describes a hierarchical classification of natural communities that was developed in the 1990s by a team of several groups and many scientists. These seem to be the same as the Hawaii Biodiversity and Mapping Program designations.
The initial hierarchy is based primarily on ecological systems which are suites of ecologically linked natural communities sharing similar biogeoclimatic conditions – specifically elevation and moisture. It then proceeds lower in the hierarchy to physiognomy. They term it the Elevation-Moisture-Physiognomy (EMP) hierarchy. An example description on the website is: “a vegetation type at 4500 feet elevation, receiving 250 inches annual rainfall, and dominated by trees would be classified as a ‘Montane Wet Fores’.” The lowest hierarchical level is then classified into types and subtypes with community types typically defined by dominant genera and subtypes be species of dominant plants. The complete hierarchy gives the description of one of the terrestrial natural communities.
The ecoregion plan website also states the following: “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, Atlas of Hawaiʻi). Hawai‘i supports more Holdridge life form categories than any other ecoregion known (Tosi et al. 2001, Ewell 2004).”
It should be noted that most of the material on the ecoregion website was developed in the 1990s with some (minor?) modifications through 2006. It seems that it has not for the most part been updated much since. The introduction page does state that the website is an archive and directs the viewer to current projects at its website here: https://www.nature.org/en-us/about-us/where-we-work/united-states/hawaii/?intc=nature.tnav.ourwork.
The ecoregions website home page has the following links:
TNC Action Sites
Maps & Figures
The document Hawaiʻi’s extinction crisis: A call to action issued by the Hawaiʻi Department of Land and Natural Resources, United States Fish and Wildlife Service, and the Nature Conservancy of Hawaiʻi in 1992 states that for terrestrial native natural communities 85 of 150 are critically endangered. It appears that they were referring to the natural community designations described on the ecoregions website mentioned above. Some but not all of the natural communities are listed on the ecoregions website, in particular those within specific Conservation Areas designated here (http://www.hawaiiecoregionplan.info/portfolio.html) and listed below.
Although no longer reflective of current priorities of the Nature Conservancy in Hawaiʻi the Conservation Areas designated that have specific natural commmunities designated also have descriptions and maps with important information for the areas.
Kaua‘i Conservation Area
Kaua‘i Waterbird Conservation Area
Kaua‘i Forest Bird Conservation Area
Wai‘anae Conservation Area
Ko‘olau Conservation Area
O‘ahu Waterbird Conservation Area
East Moloka‘i Conservation Area
Maui Nui Waterbird Conservation Area
East Maui Forest Bird Conservation Area
East Maui Conservation Area
West Maui Conservation Area
Hawai‘i Waterbird Conservation Area
Hawai‘i Forest Bird Conservation Area
Kohala Conservation Area
Mauna Kea Conservation Area
Windward Mauna Loa Conservation Area
Ka‘ū – Kapāpala Conservation Area
Kona Conservation Area
Pōhakuloa – Pu‘u Wa‘awa‘a Conservation Area
The natural community descriptions do not seem to be available directly available online, however there are short descriptions available for 86 communities defined (as of about 1998?) that were ranked as critically imperiled, imperiled, or vulnerable (G1, G2, and G3, respectively) at an archived HBMP website here: https://web.archive.org/web/20100610152809/http:/hbmp.Hawaii.edu/hbmp/trackedcommunities.asp. Note that on the website is the note ‘Communities tracked by HBMP (n=138)’ which is close to the 150 mentioned on the ecoregions website.
The Hawaiʻi Manual of Flowering Plants (1999) lists 106 plant communities with good descriptions but there appears to be no current status evaluation for those communities.
The Hawai‘i Biodiversity & Mapping Program (HBMP) program, as described at http://hbmpweb.pbrc.hawaii.edu/ccrt/hbmp has apparently not been active for a number of years. The website has the following statement: “The Hawai‘i Biodiversity & Mapping Program (HBMP) is a research program within the Center for Conservation Research and Training (CCRT), Pacific BioSciences Research Center (PBRC) at the University of Hawai‘i”. HBMP is also a member of NatureServe, an international network of databases. The HBMP does have one of the most comprehensive database and distribution records of Hawaiʻi’s rare and endangered species but it seems has not been active since sometime in the mid-2000s.
An archived website of the HMBP lists and describes (where data is available) 86 natural communities tracked by HBMP (it also has a note “n=138”): https://web.archive.org/web/20100610152809/http://hbmp.hawaii.edu/hbmp/trackedcommunities.asp.
Other categories are also sometimes used. Landfire mapping of natural communities: https://www.fs.fed.us/database/feis/fire_regimes/Hawaii/all.html#Distribution. Landfire data access and download is available here: https://www.landfire.gov/getdata.php. The USFWS uses 11 broad categories of ecosystems when establishing critical habitat. The Hawaiʻi Statewide Assessment of Forest Conditions and Trends: 2010 document (https://dlnr.hawaii.gov/forestry/files/2013/09/SWARS-Entire-Assessment-and-Strategy.pdf) maps 22 different “landcovers”.