Environmental and evolutionary drivers of diversity patterns in the tea family (Theaceae s.s.) across China

Rao M, Steinbauer M, Xiang X, Mi X, Zhang J, Svenning JC (2018)

Publication Language: English

Publication Type: Journal article, Original article

Publication year: 2018


Pages Range: in press


Subtropical forest is recognized as an important global vegetation type with high levels of plant species richness. However, the mechanisms underlying its diversity are still poorly understood. Notably, species richness may be controlled by contemporary environment, but also by evolutionary dynamics (e.g., time-for-speciation or evolutionary rates), with the latter predicting relations between species richness and phylogenetic assemblage structure. Here, we assess the relative roles of these factors in shaping species diversity patterns at several taxonomic scales in a major subtropical plant group, the tea family (Theaceae s.s.) across China (145 species). To this end, we assessed the inter-relations between species richness, phylogenetic assemblage structure (net related index) and key environmental variables (minimum temperature of the coldest month, mean annual precipitation, soil pH), using generalized linear models and spatial linear models. We found that species richness is significantly related to environmental variables, especially decreasing with soil pH both across the whole family and within the tribe Theeae. Family-level species richness is unrelated to phylogenetic structure, providing no support for time-for-speciation or evolutionary rate effects. However, within the tribe Theeae, species richness was related to phylogenetic structure with an U-shaped relationship, a more complex relation than time-for-speciation or evolutionary rate hypothesis would predict. Overall, these results suggest that Theaceae species richness patterns within China are primarily driven by shallow-time environmentally-driven dynamics, albeit the nested patterns of its subgroups (notably Theeae) exhibit evolutionarily linked patterns. Our findings show that environmental and evolutionary processes interact in complex ways to shape species richness patterns within the subtropical forest biome.

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Rao, M., Steinbauer, M., Xiang, X., Mi, X., Zhang, J., & Svenning, J.-C. (2018). Environmental and evolutionary drivers of diversity patterns in the tea family (Theaceae s.s.) across China. Ecology and Evolution, in press.


Rao, Mide, et al. "Environmental and evolutionary drivers of diversity patterns in the tea family (Theaceae s.s.) across China." Ecology and Evolution (2018): in press.

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