Topographic History of the Maui Nui Complex, Hawai'i, and Its Implications for Biogeography

Abstract

Abstract:The Maui Nui complex of the Hawaiian Islands consists of the islands of Maui, Moloka'i, Lana'i, and Kaho'olawe, which were connected as a single landmass in the past. Aspects of volcanic landform construction, island subsidence, and erosion were modeled to reconstruct the physical history of this complex. This model estimates the timing, duration, and topographic attributes of different island configurations by accounting for volcano growth and subsidence, changes in sea level, and geomorphological processes. The model indicates that Maui Nui was a single landmass that reached its maximum areal extent around 1.2 Ma, when it was larger than the current island of Hawai'i. As subsidence ensued, the island divided during high sea stands of interglacial periods starting around 0.6 Ma; however during lower sea stands of glacial periods, islands reunited. The net effect is that the Maui Nui complex was a single large landmass for more than 75% of its history and included a high proportion of lowland area compared with the contemporary landscape. Because the Hawaiian Archipelago is an isolated system where most of the biota is a result of in situ evolution, landscape history is an important detertninant of biogeographic patterns. Maui Nui's historical landscape contrasts sharply with the current landscape but is equally relevant to biogeographical analyses.THE HAWAIIAN ISLANDS present an ideal setting in which to weigh the relative influences of ecological phenomena (concerned with local conditions and species interactions) and historical phenomena (concerned with dispersal and speciation) on the composition of species assemblages. Environmental gradients such as elevation and moisture are very readily studied in the Hawaiian Islands, as compared with many regions. The Islands also span a remarkable time line of geo-

The Mecyclothorax beetles (Coleoptera, Carabidae, Moriomorphini) of West Maui, Hawaii: taxonomy, biogeography, and conservation

“…The integration of data on rate of shield-building volcanism, the rate and amount of island subsidence due to loading of the Pacific Plate by newer volcanoes, and the amount of eustatic sea-level change allowed Price & Elliott-Fisk (2004) to estimate that West Maui lost direct connection with Molokai about 700,000 years ago due to incursion of the sea into what is now the Pailolo Channel. At that time West and East Maui were connected by a saddle estimated to be about 500 m elevation, based on a total subsidence of that part of Maui by 800 m over the past 1.2 Myr.…”

“…During their orogenic history, today's Hawaiian islands have been born as isolated oceanic volcanoes, then coalesced into larger super-islands which have then been subsequently fragmented through the actions of massive land slides (Moore et al 1989), subsidence, and eustatic sea-level changes (Price & Elliott-Fisk 2004). Among these island fragments lies West Maui (Fig.…”

Taxonomic Revision of the Endangered Hawaiian Red-flowered Sandalwoods (<I>Santalum</I>) and Discovery of an Ancient Hybrid Species

“…This first colonizer likely soon dispersed to the neighboring island of O`ahu sometime after and resulted in a single species, S. freycinetianum. Subsequently, a colonization from O`ahu to the Maui Nui complex occurred prior to the separation of the Maui Nui complex, in which the islands of Maui, Lana`i, Moloka`i, and Kaho`olawe were connected as a single landmass, which began to break apart approximately 0.6 Ma, but after the island of Moloka`i was separated from O`ahu, which was briefly connected via the Penguin Bank shoal until about 2 Ma ( Price and Elliott-Fisk 2004 ); this colonization resulted in S. haleakalae including varieties haleakalae and lanaiense, which occurs throughout all island once included in the Maui Nui complex.…”

Dubautia carrii and D. hanaulaensis, New Species of the Hawaiian Silversword Alliance (Compositae, Madiinae) from Moloka‘i and Maui

“…Biogeography --The results from the current study suggest that the initial colonization event of Santalum from Subsequently, a colonization from O`ahu to the Maui Nui complex occurred prior to the separation of the Maui Nui complex, in which the islands of Maui, Lana`i, Moloka`i, and Kaho`olawe were connected as a single landmass, which began to break apart approximately 0.6 Ma, but after the island of Moloka`i was separated from O`ahu, which was briefly connected via the Penguin Bank shoal until about 2 Ma ( Price and Elliott-Fisk 2004 ); this colonization resulted in S. haleakalae including varieties haleakalae and lanaiense, which occurs throughout all island once included in the Maui Nui complex.…”