Geographic patterns and environmental correlates of taxonomic and phylogenetic beta diversity for large‐scale angiosperm assemblages in China

Abstract

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.

Plant taxonomic and phylogenetic turnover increases toward climatic extremes and depends on historical factors in European beech forests

“…For each plot, we obtained data on species occurrences and selected only angiosperms, thus excluding gymnosperms, pteridophytes, lycophytes, and non-vascular plants (~4% of total species). We focused on angiosperms to avoid inflated results due to a few taxa connected to deep phylogenetic nodes (Massante & Gerhold, 2020;Qian et al, 2020; see Appendix S2 for further justification and results including all vascular plants). We standardized the species names in our data set according to The Plant List using the R package "Taxonstand" (Cayuela et al, 2017).…”

“…This metric is equivalent to the "local contribution to beta-diversity" proposed by Legendre and De Cáceres (2013). We preferred this approach over a moving window approach, which calculates beta-diversity among a group of adjacent cells (e.g., Peixoto et al, 2017;Qian et al, 2020), because we were interested in comparing areas based on their absolute levels of turnover rather than identifying areas where the local rate of change in turnover was maximum. This corresponds to the difference between the second and the third level of abstraction in beta-diversity analyses according to Tuomisto and Ruokolainen (2006).…”

Quaternary climate change explains global patterns of tree beta-diversity

“…10 ). However, these findings are primarily based on analyses of spatial patterns of local species richness (alpha-diversity), spatial variability in species composition among sites (beta-diversity) at large scales have received less attention 10,14–19 . Because species richness is strongly determined by contemporary climatic conditions 20,21 , which are usually correlated with paleoclimates, the extent to which historical environmental conditions shape present-day biodiversity is still under debate 22–24 .…”

“…Because species richness is strongly determined by contemporary climatic conditions 20,21 , which are usually correlated with paleoclimates, the extent to which historical environmental conditions shape present-day biodiversity is still under debate 22–24 . Compared to alpha-diversity, beta-diversity considers not only the number of species but also their identities, it thus provides a way to examine how biodiversity changes across space and can enhance understanding of processes shaping biodiversity patterns 14,17–19,25 .…”

“…To detect processes of past climate change shaping beta-diversity, it is important to partition beta-diversity into two additive components: spatial species turnover and nestedness of assemblages 15,19,25–28 . Spatial species turnover reflects species replacement between sites, while nestedness describes the extent to which depauperate assemblages are subsets of richer ones, reflecting species loss across sites 25 .…”