Significance: Ecological and evolutionary processes work together in the assembly of regional and local communities from available species pools based on species traits linked to ecological tolerances. Because phylogenies summarize the evolutionary history of the clades within them, phylogeny-based approaches are essential to understanding the origin of variation in species richness across environmental gradients. Here, we analyze, within a phylogenetic context, a comprehensive dataset on the distributions of seed plants in China. Specifically, we examined relationships between indices of phylogenetic structure and environment for individual clades, from taxonomic families to the root of the phylogeny of the Chinese seed plants. We found that phylogenetic niche conservatism plays an important role in the assembly of regional floras in China.

Yunnan, located in southwestern China, harbors more than 19,000 higher plants, which represents the highest plant diversity in the country. However, plant diversity in Yunnan faces enormous threats today, including habitat destruction and fragmentation, environmental pollution, and over-exploitation of natural resources. Despite recent efforts to protect biodiversity, there are still thousands of threatened species, some of which have become extinct. We analyzed available data to gain a greater understanding of plant diversity and the status of plant conservation in Yunnan. We found that southern, southeastern, and northwestern Yunnan are hotspots of total species, endemic species, specimens, new species and threatened species, whereas southeastern Yunnan is a hotspot for plant species with extremely small populations. Moreover, we found that there are still conservation gaps and poorly protected areas in central, eastern, and northeastern Yunnan. We conclude that conservation of plant diversity in Yunnan requires modern field investigation, systematic research, the development of comprehensive databases, and government support. We recommend that conservationists pay more attention to building and improving functional protection systems and popularizing science.

A full understanding of the origin and maintenance of β‐diversity patterns in a region requires exploring the relationships of both taxonomic and phylogenetic β‐diversity (TBD and PBD, respectively), and their respective turnover and nestedness components, with geographic and environmental distances. Here, we simultaneously investigated all these aspects of β‐diversity for angiosperms in China. Specifically, we evaluated the relative importance of environmental filtering vs dispersal limitation processes in shaping β‐diversity patterns. We found that TBD and PBD as quantified using a moving window approach decreased towards higher latitudes across the whole of China, and their turnover components were correlated with latitude more strongly than their nestedness components. When quantifying β‐diversity as pairwise distances, geographic and climatic distances across China together explained 60 and 53% of the variation in TBD and PBD, respectively. After the variation in β‐diversity explained by climatic distance was accounted for, geographic distance independently explained about 23 and 12% of the variation in TBD and PBD, respectively, across China. Overall, our results suggest that environmental filtering based on climatic tolerance conserved across lineages is the main force shaping β‐diversity patterns for angiosperms in China.