ISLA Federico Ignacio
Highstands of the sea level and the speciation of coastal communities: opportunities for the new territories in southern South America
Boletin de biodiversidad de Chile
Lugar: Osorno; Año: 2012 vol. 7 p. 45 - 59
The sea-level fluctuation during the Holocene has induced the emergence of new geographical extensions constrained by some conditioning factors as salinity regimes, habitats and substrates. At the coast of Argentina, some organisms have taken advantage of these factors. A genera of the rissoidean snail, Heleobia australis (D?Orbigny 1835), has colonised estuarine areas (mudflats, coastal lagoons, estuaries) with significant changes in regard to the salinity regime. The rodent Ctenomys australis (Rusconi 1934) has specialized to live on barrier dunes, environments significantly different from those occupied by the ancient lineages of this family. In Patagonia, embayments between headlands have changed in their sediment availability during the different highstands of the Quaternary. Benthic communities were therefore more related to the changes of the bottom composition of these marine terraces than to sea surface temperatures. The Holocene jumps of the sea level could have caused similar rapid effects when the sea surpassed certain levels causing the approximately-sudden flood of a former subaerial depression.