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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.


Visualization of a global data set of angiosperm macrofossil occurrences downloaded from the Paleobiology database as described by Silvestro et al. (2015). The data set included 9665 records, representing a total of 297 fossil taxa identified to the genus level. In this figure, all records were subdivided by country and time period, according to the Geological Time Scale of Gradstein et al. (2012).
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Figure 1: Visualization of a global data set of angiosperm macrofossil occurrences downloaded from the Paleobiology database as described by Silvestro et al. (2015). The data set included 9665 records, representing a total of 297 fossil taxa identified to the genus level. In this figure, all records were subdivided by country and time period, according to the Geological Time Scale of Gradstein et al. (2012).

Mentions: We explored whether fossils could be used to infer diversity trends through time, as has been recently demonstrated for fossil rich clades such as mammals (Silvestro et al., 2014). For this we assessed a global data set of angiosperm macrofossil occurrences originally downloaded from the Paleobiology database (https://www.paleobiodb.org) as described by Silvestro et al. (2015). The data set included 9,665 records, representing a total of 297 fossil taxa identified to the genus level; identifications below the generic level were grouped by genus. To investigate potential biases in the data, all records were subdivided by country and time period (from the Lower Cretaceous to today), according to the Geological Time Scale of Gradstein et al. (2012). Unfortunately, a visual inspection of the data (Figure 1) showed severe spatial and temporal biases. These biases precluded any sensible analyses of diversity changes in tropical regions, and we were therefore forced to rely on species distribution and molecular data alone.


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)

Visualization of a global data set of angiosperm macrofossil occurrences downloaded from the Paleobiology database as described by Silvestro et al. (2015). The data set included 9665 records, representing a total of 297 fossil taxa identified to the genus level. In this figure, all records were subdivided by country and time period, according to the Geological Time Scale of Gradstein et al. (2012).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 1: Visualization of a global data set of angiosperm macrofossil occurrences downloaded from the Paleobiology database as described by Silvestro et al. (2015). The data set included 9665 records, representing a total of 297 fossil taxa identified to the genus level. In this figure, all records were subdivided by country and time period, according to the Geological Time Scale of Gradstein et al. (2012).
Mentions: We explored whether fossils could be used to infer diversity trends through time, as has been recently demonstrated for fossil rich clades such as mammals (Silvestro et al., 2014). For this we assessed a global data set of angiosperm macrofossil occurrences originally downloaded from the Paleobiology database (https://www.paleobiodb.org) as described by Silvestro et al. (2015). The data set included 9,665 records, representing a total of 297 fossil taxa identified to the genus level; identifications below the generic level were grouped by genus. To investigate potential biases in the data, all records were subdivided by country and time period (from the Lower Cretaceous to today), according to the Geological Time Scale of Gradstein et al. (2012). Unfortunately, a visual inspection of the data (Figure 1) showed severe spatial and temporal biases. These biases precluded any sensible analyses of diversity changes in tropical regions, and we were therefore forced to rely on species distribution and molecular data alone.

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.