Biogeography: how do reefs differ? Reefs are found all over the tropical world. Not all reefs are alike, though. The reefs with the most biodiversity, or different types of plants and animals, are found in the far western Pacific and south-east Asia. As reefs occur farther and farther from this rich "center" numbers of different organisms goes down. There are about 1,000 species of fish in American Samoa (as opposed to 2,000 in Australia), and less than 500 in Hawai'i. Corals, too, are fewer as you get farther east. In Samoa there are about 200 species, but in Hawai'i, which sits isolated in the northern hemisphere, there are only about 50 species. Atlantic reefs have even lower diversity compared to Pacific reefs. Why? There are many reasons. Small island ecosystems cannot support the great diversity that a larger area, such as Australia Great Barrier Reef, can. Also, the huge distances between islands means that fewer plants and animals survive the long ocean journeys which allow them to colonize remote islands. Can you think of other reasons? Ese'esega o a'au? O a'au e maua i itu vevela ole lalolagi, e ui lava ina 'ese'ese ituaiga a'au. Ole itu i Sisfo ole Pasefika ma Saute Sasae o Asia, o ogasami ia e pito i sili ona tele ai ituaiga meaola ma laau ese'ese o maua ai. O le mamao ese o a'au mai ia ogasami o le faaiti'itia foi lea o le tele o meaola ese'ese o maua ai. E tusa ma le tasi le afe (1,000) ituaiga i'a o loo maua i Amerika Samoa (e fatusatusa ma le 2.000 o lo'o maua i Ausetalia), ae tusa e 500 ituaiga i'a a i Hawaii. I Amerika Samoa, e tusa ma le 200 ituaiga 'amu o lo'o maua ai, ae tusa ma le 50 ituaiga i Hawaii. O ese foi ituaiga a'au o maua i le sami o Atalani ma e laititi lava ituaiga meaola ese'ese o maua ai. Pe aisea? E tele mafua'aga. E le mafai e motu laiti ona sapasapaia le tele o meaole eseese e pei ona maua i nofoaga tetele e i ai a'au tele i Ausetalia. O le vava mamao o motu ua le mafai ai ona feaveai meaola mai le isi motu i le isi. Pe ete iloa nisi mafua'aga? Na mea 'oko'a ma waena o na ko'aka like 'ole? Loa'a na ko'aka ma ka honua holo'oko'a. Aka, like'ole na ko'aka. Loa'a na ko'aka like'ole i ka Pakipika komoohana mamao a me Asia hema-hikina. I ka hele 'ana akula mai keia "piko" mai, emi 'ia na mea 'oko'a. Aia ho'okahi kaukini ano i'a ma Samoa Amelika (like'ole me 2,000 ma Australia) a emi iho 500 ma Hawai'i nei. Ho'emi'ia na ano ko'a pu mai ka hikina aku. Ma Samoa aia ea 'ano o 200 'oi a emi mai, aka i Hawai'i, ma ka 'ao'ao 'akau, aia aa 'ano 50. Ua 'oi aku ka like 'ole o na na ko'aka Atenalika ma mua o na Pakipika. No ke aha la? Ua nui na kumu. 'A'ole hiki i na mokupuni iki ke kako'o i na mea like 'ole e like me kekahi wahi nunui 'oia ho'i 'o "Australia Great Barrier Reef." A me na mile nunui ma waena o na mokupuni, 'noemi 'io ka helu o na mea me ka 'ikaika lawa e ho'ola i na holo 'ana ma ka moana.

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