Endemism in the Hawaiian Islands refers to the fact that the islands are home to a large number of endemic species unique to the archipelago.
Located nearly 2,400 miles (about 3,900 km) from the nearest continental shore, the Hawaiian Islands are the most isolated group of islands on the planet. The plant and animal life of the Hawaiian archipelago is the result of early, very infrequent colonizations of arriving species and the slow evolution of those species—in isolation from the rest of the world's flora and fauna—over a period of at least 5 million years. As a consequence, Hawai'i is home to a large number of endemic species. The radiation of species described by Charles Darwin in the Galapagos Islands which was critical to the formulation of his theory of evolution is far exceeded in the more isolated Hawaiian Islands.
The relatively short time that the existing main islands of the archipelago have been above the surface of the ocean (less than 10 million years) is only a fraction of time span over which biological colonization and evolution have occurred in the archipelago. High, volcanic islands have existed in the Pacific far longer, extending in a chain to the northwest; these once mountainous islands are now reduced to submerged banks and coral atolls. Midway Atoll, for example, formed as a volcanic island some 28 million years ago. Kure Atoll, a little further to the northwest, is near the Darwin point—defined as waters of a temperature that allows coral reef development to just keep up with isostatic sinking. And extending back in time before Kure, an even older chain of islands spreads northward nearly to the Aleutian Islands; these former islands, all north of the Darwin point, are now completely submerged as the Emperor Seamounts.
The islands are well known for the environmental diversity that occurs on high mountains within a trade winds field. On a single island, the climate can differ around the coast from dry tropical (< 20 in or 500 mm annual rainfall) to wet tropical; and up the slopes from tropical rainforest (> 200 in or 5,000 mm per year) through a temperate climate into alpine conditions of cold and dry climate. The rainy climate impacts soil development, which largely determines ground permeability, which affects the distribution of streams, wetlands, and wet places.
The distance and remoteness of the Hawaiian archipelago is a biological filter. Seeds or spores attached to a lost migrating bird's feather or an insect falling out of the high winds found a place to survive in the islands and whatever else was needed to reproduce. The narrowing of the gene pool meant that at the very beginning, the population of a colonizing species was a bit different from that of the remote contributing population. This list does not include species extinct in prehistoric times.
Island formation Throughout time, the Hawaiian Islands formed linearly from northwest to the southeast. A study was conducted to determine the approximate ages of the Hawaiian Islands using K–Ar dating of the oldest found igneous rocks from each island. Kauai was determined to be about 5.1 million years old, Oahu about 3.7 million years old and the youngest island of Hawaii about 0.43 million years old. By determining the maximum age of the islands, inferences could be made about the maximum possible age of organisms inhabiting the island. The newly formed islands were able to accommodate growing populations, while the new environments were causing high rates of new adaptations.
Human arrival Human contact, first by Polynesians and later by Europeans, has had a significant impact. Both the Polynesians and Europeans cleared native forests and introduced non-indigenous species for agriculture (or by accident), driving many endemic species to extinction. Fossil finds in caves, lava tubes, and sand dunes have revealed an avifauna that once had a native eagle, two raven-size crows, several bird-eating owls, and giant ducks known as moa-nalos. Around 861 species of plants have been introduced to the islands by humans since its discovery by Polynesian settlers, including crops such as taro and breadfruit.
Today, many of the remaining endemic species of plants and animals in the Hawaiian Islands are considered endangered, and some critically so. Plant species are particularly at risk: out of a total of 2,690 plant species, 946 are non-indigenous with 800 of the native species listed as endangered.
Terrestrial vertebrates Mammals Hawaiian hoary bat (a.k.a. ʻŌpeʻapeʻa) (Lasiurus semotus) - endangered Hawaiian monk seal (a.k.a. ʻIlio-holo-i-ka-uaua) (Neomonachus schauinslandi) - endangered Synemporion keana (a species of vesper bat) - extinct
Birds Hawaiian duck (a.k.a. Koloa) (Anas wyvilliana) - endangered Laysan duck (Anas laysanensis) - critically endangered Nene (a.k.a. Hawaiian goose) (Branta sandvicensis) - near threatened Hawaiian petrel (Pterodroma sandwichensis) - endangered Newell's shearwater (a.k.a. Hawaiian shearwater or 'a'o) (Puffinus newelli) - critically endangered Hawaiian hawk (a.k.a. 'Io) (Buteo solitarius) - near threatened Laysan rail (Porzana palmeri) - extinct Hawaiian rail (Porzana sandwichensis) - extinct Hawaiian gallinule (Gallinula chloropus sanvicensis) Hawaiian coot (Fulica alai) - vulnerable Hawaiian stilt (Himantopus himantopus knudseni) Hawaiian black noddy (Anous minutus melanogenys) Pueo (Asio flammeus sandwichensis) - endangered Kauaʻi oʻo (Moho braccatus) - extinct Oʻahu ʻōʻō (Moho apicalis) - extinct Molokaʻi ʻōʻō (Moho bishopi) - extinct Hawaiʻi ʻōʻō (Moho nobilis) - extinct Kioea (Chaetoptila angustipluma) - extinct Kāmaʻo (Myadestes myadestinus) - extinct Puaiohi (Myadestes palmeri) - critically endangered Olomaʻo (Myadestes lanaiensis) - critically endangered/extinct ʻĀmaui (Myadestes lanaiensis woahensis) - extinct ʻŌmaʻo (Myadestes obscurus) - vulnerable Millerbird (Acrocephalus familiaris) - critically endangered Hawaiʻi ʻelepaio (Chasiempis sandwichensis) - vulnerable Oʻahu ʻelepaio (Chasiempis ibidis) - endangered Kauaʻi ʻelepaio (Chasiempis sclateri) - vulnerable Hawaiian crow (Corvus hawaiiensis) - extinct in the wild Laysan finch (Telespiza cantans) - vulnerable Nīhoa finch (Telespiza ultima) - critically endangered Lesser koa finch (Rhodacanthus flaviceps) - extinct Greater koa finch (Rhodacanthus palmeri) - extinct Maui parrotbill (Pseudonestor xanthophrys) - critically endangered ʻŌʻū (Psittirostra psittacea) - critically endangered/extinct Palila (Loxioides bailleui) - critically endangered Lanaʻi hookbill (Dysmorodrepanis munroi) - extinct Kona grosbeak (Chlroidops kona) - extinct Common ʻamakihi (Hemignathus virens) - least concern Oʻahu ʻamakihi (Hemignathus flavus) - vulnerable Kauaʻi ʻamakihi (Hemignathus kauaiensis) - vulnerable Greater ʻamakihi (Hemignathus sagittirostris) - extinct Maui nukupuʻu (Hemignathus affinis) - critically endangered/extinct Kauaʻi nukupuʻu (Hemignathus hanapepe) - critically endangered/extinct Oʻahu nukupuʻu (Hemignathus lucidus) - extinct ʻAkiapolaʻau (Hemignathus munroi) - endangered ʻAnianiau (Magumma parva) - vulnerable Hawaiʻi ʻakialoa (Akialoa obscura) - extinct Kauaʻi ʻakialoa (Akialoa stejnegeri) - extinct Maui Nui ʻakialoa (Akialoa lanaiensis)- extinct Oahu ʻakialoa (Akialoa ellisiana) - extinct ʻAkekeʻe (Loxops caeruleirostris) - critically endangered Hawaiʻi ʻākepa (Loxops coccineus) - endangered Maui ʻākepa (Loxops ochraceus) - extinct Oʻahu ʻākepa (Loxops wolstenholmei) - extinct ʻAkikiki (Oreomystis bairdi) - critically endangered Hawaiʻi creeper (Oreomystis mana) - endangered Molokai creeper (Paroreomyza flammea) - extinct Oʻahu ʻalauahio (Paroreomyza maculata) - critically endangered/extinct Maui ʻalauahio (Paroreomyza montana) - endangered Lanaʻi ʻalauahio (Paroreomyza montana montana) - extinct ʻAkohekohe (a.k.a. Crested honeycreeper) (Palmeria dolei) - critically endangered Poʻouli (Melamprosops phaeosoma) - critically endangered/extinct ʻUla-ʻai-hāwane (Ciridops anna) - extinct ʻIʻiwi (a.k.a. Scarlet honeycreeper) (Drepanis coccinea) - vulnerable Hawaiʻi mamo (Drepanis pacifica) - extinct Black mamo (Drepanis funerea) - extinct Laysan honeycreeper (Himantione fraithii) - extinct ʻApapane (Himantione sanguinea) - least concern
Freshwater fishes None of Hawaii's native fish are entirely restricted to freshwater (all are either anadromous, or also found in brackish and marine water in their adult stage).
(Awaous stamineus)Lindstrom, D.P., M.J. Blum, R.P. Walter, R.B. Gagne and J.F. Gilliam, 2012. Molecular and morphological evidence of distinct evolutionary lineages of Awaous guamensis in Hawai’i and Guam. Copeia (2):293-300. (Kuhlia xenura) (Lentipes concolor) - data deficient (Stenogobius hawaiiensis) (Eleotris sandwicensis) - data deficient (Sicyopterus stimpsoni) - near threatened
Terrestrial invertebrates
Insects Hyposmocoma (a genus of moths, such as the snail-eating caterpillar) Agrotis (a genus of moths) Drosophila (a genus of flies) Campsicnemus mirabilis (an extinct species of fly) Campsicnemus brevipes (a species of fly) Paralopostega (a genus of moths) Mestolobes (a genus of moths) Hypena (a genus of moths) Orthomecyna (a genus of moths) Helicoverpa (a genus of moths) Scotorythra (a genus of moths) Genophantis (a genus of moths) Tritocleis (a genus of moths) Eurynogaster (a genus of flies) Kamehameha butterfly (a.k.a. Pulelehua) (Vanessa tameamea) Green Hawaiian blue (Udara blackburni) Longhead yellow-faced bee (a.k.a. the Hawaiian yellow-faced bee) (Hylaeus longiceps) Thaumatogryllus (a genus of crickets) Wēkiu bug (Nysius wekiuicola) Drosophila sharpi (a rare species of fly) Koʻolau spurwing long-legged fly (an extinct species of fly) Lanai pomace fly (an extinct species of fly) Phyllococcus oahuensis (a species of mealybug) Megalagrion (a genus of damselfly) Clavicoccus (a genus of mealybug) Dryophthorus distinguendus (a species of weevil) Laysan weevil (an extinct species of weevil) Rhyncogonus bryani (an extinct species of weevil) Manduca blackburni (an endangered species of hawkmoth) Thyrocopa (a genus of moths) Caconemobius nori (a species of cricket) Caconemobius howarthi (a species of cricket) Caconemobius schauinslandi (a species of cricket) Caconemobius varius (a species of cricket)
Crustaceans Atyoida bisulcata (a freshwater shrimp) Halocaridina (a genus of marine and brackish water shrimp) Hawaiian river shrimp (Macrobrachium grandimanus)
Spiders Ariamnes makue (a species of spider) Happy face spider (Theridion grallator) Kauaʻi cave wolf spider (Adelocosa anops) - endangered Orsonwelles, a genus of 13 species, each endemic to a single island Nihoa (a genus of spiders) Lycosa hawaiiensis (a species of spider)
Gastropods Gastropods are snails. Oahu tree snails (Achatinella) - threatened, several already extinct Auriculella (a genus of land snails) - threatened, several already extinct Amastra (a genus of land snails) - many species extinct Carelia (a genus of land snails) - entire genus extinct Erinna (a genus of freshwater snails) - one vulnerable species, the other possibly extinct Gulickia alexandri (a land snail) - critically endangered Newcombia (a genus of land snails) - threatened, one already extinct Neritina granosa (a freshwater snail) - vulnerable Perdicella (a genus of land snails) - threatened, several already extinct Partulina (a genus of land snails) - threatened, several already extinct
Marine animals
Marine fishes
Cnidarians Finger coral (Porites compressa) Thick finger coral (Porites duerdeni) Brigham's coral (Porites brighami) Molokaʻi cauliflower coral (Pocillopora molokensis) Irregular rice coral (Montipora dilatata) Blue rice coral (Montipora flabellata) Sandpaper or Ringed rice coral (Montipora patula) Verril's lump coral (Psammocora verrilli) Serpentine cup coral (Eguchipsammia serpentina)