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Allopatric or sympatric speciation influence the degree to which closely related
species coexist in different manners, altering the patterns of phylogenetic structure
and turnover among and between communities. The objective of this study
was to examine whether phylogenetic community structure and turnover in the
Brazilian Atlantic Forest permit conclusions about the dominant process for the
formation of extant angiosperm richness of tree species. Therefore, we analyzed
phylogenetic community structure (MPD, MNTD) as well as taxonomic (Jaccard
similarity) and phylogenetic turnover (betaMPD, betaMNTD) among and
between 49 tree communities distributed among three different habitat types.
Mean annual precipitation and mean annual temperature in each survey area
were estimated. Phylogenetic community structure does not differ between
habitat types, although MPD reduces with mean annual temperature. Jaccard
similarity decreases and betaMNTD increases with spatial distance and environmental
differences between study sites. Spatial distance explains the largest portions
of variance in the data, indicating dispersal limitation and the spatial
aggregation of recently formed taxa, as betaMNTD is related to more recent
evolutionary events. betaMPD, that is related to deep evolutionary splits, shows
no spatial or environmental pattern, indicating that older clades are equally distributed
across the Brazilian Atlantic Forest. While similarity pattern indicates
dispersal limitations, the spatial turnover of betaMNTD is consistent with a
high degree of sympatric speciation generating extant diversity and endemism
in the Brazilian Atlantic Forest. More comprehensive approaches are necessary
to reduce spatial sampling bias, uncertainties regarding angiosperm diversification
patterns and confirm sympatric speciation as the dominant generator for
the formation of extant species diversity in the Brazilian Atlantic Forest.