The Carnian Pluvial Episode: A damp squib for life on land?

The Carnian Pluvial Episode (CPE), a 1–2 Ma interval of enhanced humidity midway through the Triassic Period, has been implicated in high levels of biotic turnover in marine environments. The Carnian stage on land also saw major faunal and floral reorganisation, including the extinction of rhynchosaurs, the diversification of dinosaurs and the origin of crocodylomorphs and mammaliaforms. An imperfect fossil record and dating uncertainties, however, make establishing a firm link to the CPE much more difficult, but the picture is gradually improving as new evidence accumulates. We review observed terrestrial biotic changes and suggest that in most cases the effects of the CPE in isolation remain ambiguous or were relatively minor or reversible. Rather, the Carnian biotic change was probably a staggered response to a number of factors, including climatic, set against the backdrop of long-term rebuilding of ecosystems following the end-Permian mass extinction.