COMPOSITIONAL FIDELITY OF SUBFOSSIL MOLLUSK ASSEMBLAGES IN STREAMS AND LAKES OF THE SOUTHEASTERN PAMPAS, ARGENTINA

BERNAVA GUSTAVO VICENTE; TIETZE, ELEONOR; DE FRANCESCO, CLAUDIO G.

PALAIOS

SEPM-SOC SEDIMENTARY GEOLOGY

Lugar: Lawrence; Año: 2012

0883-1351

The compositional fidelity of dead assemblages—the extent to whichsubfossil remains reflect the composition, structure, and scale of the originalliving community—is an indispensable component of studies assessing thequality of the fossil record and the effects of taphonomic biases on speciescomposition and diversity. The aim of the present study is to evaluate (1) howfaithfully abundances of subfossil freshwater mollusk shells deposited in deadassemblages correspond to their abundances in the local living assemblages,(2) how reliably diversity of living assemblages is captured by dead assemblages,(3) whether spatial variation in species composition in living assemblagesis captured by dead assemblages in the southeastern Pampas,Argentina. Twenty sites corresponding to five lotic and five lentic sites fromtwo geographic areas were analyzed in terms of taxonomic composition anddiversity, and homogeneity of multivariate dispersions.We find that (1) livingand dead assemblages occupy similar portions of multivariate space and donot significantly differ in composition within an area, (2) living anddead assemblages show similar richness and evenness, and (3) betweenenvironmentdifferences in among-site variation in composition (betadiversity) captured by living assemblages are preserved by dead assemblages.Thus, the results highlight the potential these environments have to enhancethe preservation of mollusks and result in fossil assemblages that are suitablefor paleoecological and paleoenvironmental studies of freshwater ecosystems.EN ESTE ARTICULO SE ME AGRADECE LA COLABORACION