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An engine for global plant diversity: highest evolutionary turnover and emigration in the American tropics.

Antonelli A, Zizka A, Silvestro D, Scharn R, Cascales-Miñana B, Bacon CD - Front Genet (2015)

Bottom Line: Our results, based on the analysis of c. 22,600 species and c. 20 million geo-referenced occurrence records, show no significant differences between the speciation and extinction of tropical and non-tropical angiosperms.In contrast, the outstanding species richness found today in the American tropics (the Neotropics), as compared to tropical Africa and tropical Asia, is associated with significantly higher speciation and extinction rates.These results imply that the Neotropics have acted as an engine for global plant diversity.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological and Environmental Sciences, University of Gothenburg Göteborg, Sweden ; Gothenburg Botanical Garden Göteborg, Sweden.

ABSTRACT
Understanding the processes that have generated the latitudinal biodiversity gradient and the continental differences in tropical biodiversity remains a major goal of evolutionary biology. Here we estimate the timing and direction of range shifts of extant flowering plants (angiosperms) between tropical and non-tropical zones, and into and out of the major tropical regions of the world. We then calculate rates of speciation and extinction taking into account incomplete taxonomic sampling. We use a recently published fossil calibrated phylogeny and apply novel bioinformatic tools to code species into user-defined polygons. We reconstruct biogeographic history using stochastic character mapping to compute relative numbers of range shifts in proportion to the number of available lineages through time. Our results, based on the analysis of c. 22,600 species and c. 20 million geo-referenced occurrence records, show no significant differences between the speciation and extinction of tropical and non-tropical angiosperms. This suggests that at least in plants, the latitudinal biodiversity gradient primarily derives from other factors than differential rates of diversification. In contrast, the outstanding species richness found today in the American tropics (the Neotropics), as compared to tropical Africa and tropical Asia, is associated with significantly higher speciation and extinction rates. This suggests an exceedingly rapid evolutionary turnover, i.e., Neotropical species being formed and replaced by one another at unparalleled rates. In addition, tropical America stands out from other continents by having "pumped out" more species than it received through most of the last 66 million years. These results imply that the Neotropics have acted as an engine for global plant diversity.

No MeSH data available.


Results from the diversification rate analyses under the MuSSE model. (A) Speciation rates per geographic region (tropical vs. non-tropical); (B) Extinction rates per geographic region (tropical vs. non-tropical); (C) Speciation rates for the three tropic regions; (D) Extinction rates for the three tropic regions. All results are normalized against each other. Each data point represents an angiosperm plant order (Table 2). Boxes indicate the interquartile range (IQ) of all estimates, with the median shown as a horizontal line and the whiskers indicating data range outside the quantiles. ** and *** denote significant differences (p < 0.05 and p < 0.001, respectively; ANOVA). See Methods for details.
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Figure 6: Results from the diversification rate analyses under the MuSSE model. (A) Speciation rates per geographic region (tropical vs. non-tropical); (B) Extinction rates per geographic region (tropical vs. non-tropical); (C) Speciation rates for the three tropic regions; (D) Extinction rates for the three tropic regions. All results are normalized against each other. Each data point represents an angiosperm plant order (Table 2). Boxes indicate the interquartile range (IQ) of all estimates, with the median shown as a horizontal line and the whiskers indicating data range outside the quantiles. ** and *** denote significant differences (p < 0.05 and p < 0.001, respectively; ANOVA). See Methods for details.

Mentions: The region-specific rates of speciation and extinction inferred using the MuSSE model are shown in Figure 6, calculated under the sampling fractions for each order indicated in Table 2. Individual estimates are reported in Supplementary Table S1, and significance values in each set of comparisons are summarized in Table 4.


An engine for global plant diversity: highest evolutionary turnover and emigration in the American tropics.

Antonelli A, Zizka A, Silvestro D, Scharn R, Cascales-Miñana B, Bacon CD - Front Genet (2015)

Results from the diversification rate analyses under the MuSSE model. (A) Speciation rates per geographic region (tropical vs. non-tropical); (B) Extinction rates per geographic region (tropical vs. non-tropical); (C) Speciation rates for the three tropic regions; (D) Extinction rates for the three tropic regions. All results are normalized against each other. Each data point represents an angiosperm plant order (Table 2). Boxes indicate the interquartile range (IQ) of all estimates, with the median shown as a horizontal line and the whiskers indicating data range outside the quantiles. ** and *** denote significant differences (p < 0.05 and p < 0.001, respectively; ANOVA). See Methods for details.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4389561&req=5

Figure 6: Results from the diversification rate analyses under the MuSSE model. (A) Speciation rates per geographic region (tropical vs. non-tropical); (B) Extinction rates per geographic region (tropical vs. non-tropical); (C) Speciation rates for the three tropic regions; (D) Extinction rates for the three tropic regions. All results are normalized against each other. Each data point represents an angiosperm plant order (Table 2). Boxes indicate the interquartile range (IQ) of all estimates, with the median shown as a horizontal line and the whiskers indicating data range outside the quantiles. ** and *** denote significant differences (p < 0.05 and p < 0.001, respectively; ANOVA). See Methods for details.
Mentions: The region-specific rates of speciation and extinction inferred using the MuSSE model are shown in Figure 6, calculated under the sampling fractions for each order indicated in Table 2. Individual estimates are reported in Supplementary Table S1, and significance values in each set of comparisons are summarized in Table 4.

Bottom Line: Our results, based on the analysis of c. 22,600 species and c. 20 million geo-referenced occurrence records, show no significant differences between the speciation and extinction of tropical and non-tropical angiosperms.In contrast, the outstanding species richness found today in the American tropics (the Neotropics), as compared to tropical Africa and tropical Asia, is associated with significantly higher speciation and extinction rates.These results imply that the Neotropics have acted as an engine for global plant diversity.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological and Environmental Sciences, University of Gothenburg Göteborg, Sweden ; Gothenburg Botanical Garden Göteborg, Sweden.

ABSTRACT
Understanding the processes that have generated the latitudinal biodiversity gradient and the continental differences in tropical biodiversity remains a major goal of evolutionary biology. Here we estimate the timing and direction of range shifts of extant flowering plants (angiosperms) between tropical and non-tropical zones, and into and out of the major tropical regions of the world. We then calculate rates of speciation and extinction taking into account incomplete taxonomic sampling. We use a recently published fossil calibrated phylogeny and apply novel bioinformatic tools to code species into user-defined polygons. We reconstruct biogeographic history using stochastic character mapping to compute relative numbers of range shifts in proportion to the number of available lineages through time. Our results, based on the analysis of c. 22,600 species and c. 20 million geo-referenced occurrence records, show no significant differences between the speciation and extinction of tropical and non-tropical angiosperms. This suggests that at least in plants, the latitudinal biodiversity gradient primarily derives from other factors than differential rates of diversification. In contrast, the outstanding species richness found today in the American tropics (the Neotropics), as compared to tropical Africa and tropical Asia, is associated with significantly higher speciation and extinction rates. This suggests an exceedingly rapid evolutionary turnover, i.e., Neotropical species being formed and replaced by one another at unparalleled rates. In addition, tropical America stands out from other continents by having "pumped out" more species than it received through most of the last 66 million years. These results imply that the Neotropics have acted as an engine for global plant diversity.

No MeSH data available.