Stepwise recovery of vegetation from Permian–Triassic mass extinction in North China and implications for changes of palaeoclimates

The Permian–Triassic was a major transition in the evolution of life in the earth history, when happened the greatest mass extinction during the Phanerozoic and an unusually prolonged or delayed recovery. Most studies have been carried in the marine facies while very few in the continental facies. On land, plants play a great role in the interaction of climate and terrestrial ecosystems. Here we present a regional case of stepwise recovery of vegetation in North China. Prior to the Permian–Triassic mass extinction, the voltzialean conifer forest community dominated in the Changhsingian. Consequently, the extinction event wiped out of the voltzialean conifer forest community, probably conciding with the extension of the red beds. The first post-crisis flora was an Induan herbaceous lycopsid community, succeeded by the Pleuromeia–Neocalamites shrub marsh community. A pteridosperm shrub woodland community dominated for a short time in the late Early Triassic along with the reappearance of insect herbivory. In the early Middle Triassic, gymnosperm forest communities gradually rose to predominate in both uplands and lowlands along with other diverse plant communities, indicating the beginning of the establishment of the Mesophytic Flora. In the late Middle Triassic–Late Triassic, it was occupied by the Danaeopsis–Symopteris flora and the opportunism elements gradually were replaced by the advanced taxa, which represents the complete establishment of the Mesophytic Flora.