Compositional turnover and ecological changes related to the waxing and waning of glaciers during the Late Paleozoic ice age in ice-proximal regions (Pennsylvanian, western Argentina)

The late Paleozoic ice age (LPIA) had a profound effect on the biota. Despite much research having been focused on paleotropical regions or global-scale analyses, regional ecological changes have seldom been studied in ice-proximal basins. Here, I study the compositional turnover and diversity structure across the main Carboniferous glacial event recorded in western Argentina and the subsequent nonglacial interval. Brachiopod and bivalve data from western Argentina suggest that the transition from glacial to nonglacial climates caused major compositional changes. Turnover, however, was not uniform across the bathymetric gradient, being higher in deep environments. Because extirpation was concentrated in brachiopods, but immigration was similar in both clades, the taxonomic structure of the region was significantly modified. Although regional hierarchical diversity structure and occupancy distributions remained stable, dissecting the analysis in brachiopods and bivalves underscores that ...