Landform and lithospheric development contribute to the assembly of mountain floras in China

Although it is well documented that mountains tend to exhibit high biodiversity, how geological processes affect the assemblage of montane floras is a matter of ongoing research. Here, we explore landform-specific differences among montane floras based on a dataset comprising 17,576 angiosperm species representing 140 Chinese mountain floras, which we define as the collection of all angiosperm species growing on a specific mountain. Our results show that igneous bedrock (granitic and karst-granitic landforms) is correlated with higher species richness and phylogenetic overdispersion, while the opposite is true for sedimentary bedrock (karst, Danxia, and desert landforms), which is correlated with phylogenetic clustering. Furthermore, we show that landform type was the primary determinant of the assembly of evolutionarily older species within floras, while climate was a greater determinant for younger species. Our study indicates that landform type not only affects montane species richness, but also contributes to the composition of montane floras. To explain the assembly and differentiation of mountain floras, we propose the ‘floristic geo-lithology hypothesis’, which highlights the role of bedrock and landform processes in montane floristic assembly and provides insights for future research on speciation, migration, and biodiversity in montane regions.

Wan-Yi Zhao, Zhong-Cheng Liu, Shi Shi, Jie-Lan Li, Ke-Wang Xu, Kang-You Huang, Zhi-Hui Chen, Ya-Rong Wang, Cui-Ying Huang, Yan Wang, Jing-Rui Chen, Xian-Ling Sun, Wen-Xing Liang, Wei Guo, Long-Yuan Wang, Kai-Kai Meng, Xu-Jie Li, Qian-Yi Yin, Ren-Chao Zhou, Zhao-Dong Wang, Hao Wu, Da-Fang Cui, Zhi-Yao Su, Guo-Rong Xin, Wei-Qiu Liu, Wen-Sheng Shu, Jian-Hua Jin, David E. Boufford, Qiang Fan, Lei Wang, Su-Fang Chen, Wen-Bo Liao