Intertidal Death Assemblages as Proxies of Marine Biodiversity. An Example from Northern Patagonia, Argentina

ARCHUBY, FERNANDO M; ROCHE, ANDREA

Actualistic Taphonomy in South America

Springer Nature

Lugar: Heldelberg; Año: 2019; p. 35 - 60

Marineconservation biologists have identified mollusks as one of the appropriate surrogate taxa for characterizing marine benthic diversity. In turn, live/dead comparisonstudies have overwhelmingly demonstrated that mollusk remains are faithful proxies of the mollusk composition of the living communities from which they come,with positive consequences for the paleoecological evaluation of fossilassemblages. In this contribution, we evaluate the way in which mollusk biodiversity is distributed along the lower intertidal tosupratidal (high water mark) dead shell assemblages accumulated on a northernPatagonian rocky shore, in order to explore the usefulness of these assemblagesas paleontological proxies and potential surrogates of regional biodiversity. Adiversity gradient from the lower intertidal to the supratidal was identifiedwhich is probably associated with vertical transport, although the influence ofgradients of the living community should be tested to confirm this. Theoutstanding result of this study is the discovery of high levels of diversityamong dead shells (31 bivalves and 39 gastropod species) in a single locality and with amoderate sampling effort. The supratidal death assemblage has higher speciesrichness than expected, possibly caused by stranding of the fauna after storms.Nevertheless, this level shows the lowest level of evenness and a strong biaswhen samples are not sieved through a fine mesh. The record of marine benthicdiversity in death assemblages is a promising area of research that deserves tobe explored in depth.