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Recovery of benthic marine communities from the end‐ P ermian mass extinction at the low latitudes of eastern P anthalassa
Author(s) -
Hofmann Richard,
Hautmann Michael,
Brayard Arnaud,
Nützel Alexander,
Bylund Kevin G.,
Jenks James F.,
Vennin Emmanuelle,
Olivier Nicolas,
Bucher Hugo
Publication year - 2014
Publication title -
palaeontology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.69
H-Index - 63
eISSN - 1475-4983
pISSN - 0031-0239
DOI - 10.1111/pala.12076
Subject(s) - benthic zone , paleoecology , extinction (optical mineralogy) , extinction event , ecology , ecosystem , taxon , paleontology , marine ecosystem , geology , oceanography , biology , demography , biological dispersal , population , sociology
Based on the quantitative community analysis using species‐level identifications, we track the restoration of benthic ecosystems after the end‐ P ermian mass extinction throughout the L ower T riassic of the western USA . New data on the palaeoecology of the T haynes G roup and S inbad F ormation are provided, which fill a gap between the recently studied palaeoecology of the G riesbachian– D ienerian D inwoody F ormation and the S pathian V irgin F ormation. In the S inbad F ormation and T haynes G roup, 17 species (12 genera) of bivalves, 7 species and genera of gastropods and 2 species and genera of brachiopods are recognized. The new bivalve genus C onfusionella ( P teriidae) is described. A comprehensive review of the whole L ower T riassic succession of benthic ecosystems of the western USA indicates that mid‐ and inner shelf environments show incipient recovery signals around the G riesbachian– D ienerian transition, during the S mithian and, most profound, during the early S pathian. Ecological data from youngest strata of the D inwoody F ormation as well as stratigraphic ranges of species suggest that the late D ienerian was likely a time interval of environmental stress for benthic ecosystems. Despite some evidence for short‐term environmental disturbances (e.g. shift of dominant taxa, transient drop in alpha‐diversity) during the S mithian– S pathian transition, benthic ecosystems did not show any notable taxonomic turnover at that time, in contrast to the major crisis that affected ammonoids and conodonts. Whereas alpha‐diversity of benthic communities generally increased throughout the E arly T riassic, beta‐diversity remained low, which reflects a persistently wide environmental range of benthic species. This observation is in accordance with a recently proposed model that predicts a time lag between increasing within‐habitat diversity (alpha‐diversity) and the onset of taxonomic differentiation between habitats (beta‐diversity) during biotic recoveries from mass extinction events. The observation that beta‐diversity had not significantly increased during the E arly T riassic might also provide an explanation for the comparably sluggish increase in benthic diversity during that time, which has previously been attributed to persistent environmental stress.