Abstract
Elucidating demographic history during the settlement of ecological communities is crucial to properly inferring the mechanisms that shape species diversity and their persistence through time. We used genomic data to elucidate for the first time the demographic dynamics associated with the settlement by endemic reef fish fauna of one of the most isolated islands of the Pacific Ocean, Rapa Nui (Easter Island). We compared the demographic history of nine endemic species including seven small-range (restricted to Rapa Nui and Motu Motiro Hiva) and two large-range (present in Rapa Nui and other southern subtropical islands of the Pacific) endemic species in order to explore the onset of community settlement and associated demographic history. We found that most Rapa Nui endemic species share a common demographic history, with a demographic expansion initiated during the last interglacial period and related to the last sea level high-stand. The commonality of this pattern suggests that eustatic fluctuations associated with Milankovitch cycles have played a central role in species demographic history and the final stage of contemporary community assembly of Rapa Nui reef fishes. We discuss the potential role of seamounts in the colonization / extinction / recolonization dynamics of populations of the Rapa Nui Archipelago.
Footnotes
↵† These authors jointly supervised this work.