Format: ORAL

Qiuyue Zhang1, Daniele Silvestro2*, Yaowu Xing1*

1 CAS, Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, 666303 Mengla, China 2 Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland

Understanding the causes and evolution of the phylogenetic community structure (PCS) in the geological past is critical to explaining present-day biodiversity patterns and modelling biotic responses to climate change. The paleontological record provides a unique window into the causes and evolution of community dynamics. In this study, we compiled a large fossil community data during the Cenozoic for the North temperate zone. We quantified PCS for different geological times. We thenreconstructedpaleoclimate for the fossil assemblages and fit it to PCS.We finally estimated diversification rates for woody and herbaceous plants to discuss the driving factors of the evolution of PCS.Our results showed that most fossil communities were dominated by woody taxa and there was no significant latitudinal gradient during the warm early Paleogene due to the homogeneity of the environment and similar rates for woody and herbaceous plants. The establishment of the PCS latitudinal gradient coincided with global cooling and increased seasonality and the flourishing of herbs at high latitudes. The PCS latitudinal gradient after the Middle Miocene was less steep than that of the Oligocene and closer to modern times. Our comprehensive analyses shed critical insights into the evolution of the PCS latitudinal gradients and its climatic and evolutionary driving forces.