Fossil Plant Relative Abundances Indicate Sudden Loss of Late Triassic Biodiversity in East Greenland
Jennifer C. McElwain,1,*
Peter J. Wagner,2
Stephen P. Hesselbo3
The pace of Late Triassic (LT) biodiversity loss is uncertain,
yet it could help to decipher causal mechanisms of mass extinction.
We investigated relative abundance distributions (RADs) of six
LT plant assemblages from the Kap Stewart Group, East Greenland,
to determine the pace of collapse of LT primary productivity.
RADs displayed not simply decreases in the number of taxa, but
decreases in the number of common taxa. Likelihood tests rejected
a hypothesis of continuously declining diversity. Instead, the
RAD shift occurred over the upper two-to-four fossil plant assemblages
and most likely over the last three (final 13 meters), coinciding
with increased atmospheric carbon dioxide concentration and
global warming. Thus, although the LT event did not induce mass
extinction of plant families, it accompanied major and abrupt
change in their ecology and diversity.
2 Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560, USA.
3 Department of Earth Sciences, University of Oxford, Oxford OX1 3PR, UK.
* To whom correspondence should be addressed. E-mail: jennifer.mcelwain{at}ucd.ie
