Dataset Information

Consistent phenological shifts in the making of a biodiversity hotspot: the Cape flora.

ABSTRACT:

Background

The best documented survival responses of organisms to past climate change on short (glacial-interglacial) timescales are distributional shifts. Despite ample evidence on such timescales for local adaptations of populations at specific sites, the long-term impacts of such changes on evolutionary significant units in response to past climatic change have been little documented. Here we use phylogenies to reconstruct changes in distribution and flowering ecology of the Cape flora--South Africa's biodiversity hotspot--through a period of past (Neogene and Quaternary) changes in the seasonality of rainfall over a timescale of several million years.

Results

Forty-three distributional and phenological shifts consistent with past climatic change occur across the flora, and a comparable number of clades underwent adaptive changes in their flowering phenology (9 clades; half of the clades investigated) as underwent distributional shifts (12 clades; two thirds of the clades investigated). Of extant Cape angiosperm species, 14-41% have been contributed by lineages that show distributional shifts consistent with past climate change, yet a similar proportion (14-55%) arose from lineages that shifted flowering phenology.

Conclusions

Adaptive changes in ecology at the scale we uncover in the Cape and consistent with past climatic change have not been documented for other floras. Shifts in climate tolerance appear to have been more important in this flora than is currently appreciated, and lineages that underwent such shifts went on to contribute a high proportion of the flora's extant species diversity. That shifts in phenology, on an evolutionary timescale and on such a scale, have not yet been detected for other floras is likely a result of the method used; shifts in flowering phenology cannot be detected in the fossil record.

SUBMITTER: Warren BH

PROVIDER: S-EPMC3045326 | biostudies-literature | 2011 Feb

REPOSITORIES: biostudies-literature

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Publications

Consistent phenological shifts in the making of a biodiversity hotspot: the Cape flora.

Warren Ben H BH Bakker Freek T FT Bellstedt Dirk U DU Bytebier Benny B Classen-Bockhoff Regine R Dreyer Léanne L LL Edwards Dawn D Forest Félix F Galley Chloé C Hardy Christopher R CR Linder H Peter HP Muasya A Muthama AM Mummenhoff Klaus K Oberlander Kenneth C KC Quint Marcus M Richardson James E JE Savolainen Vincent V Schrire Brian D BD van der Niet Timotheüs T Verboom G Anthony GA Yesson Christopher C Hawkins Julie A JA

BMC evolutionary biology 20110208

<h4>Background</h4>The best documented survival responses of organisms to past climate change on short (glacial-interglacial) timescales are distributional shifts. Despite ample evidence on such timescales for local adaptations of populations at specific sites, the long-term impacts of such changes on evolutionary significant units in response to past climatic change have been little documented. Here we use phylogenies to reconstruct changes in distribution and flowering ecology of the Cape flor ...[more]

PMID: 21303519

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Project description:Background and aimsIt is unclear how widespread polyploidy is throughout the largest holocentric plant family - the Cyperaceae. Because of the prevalence of chromosomal fusions and fissions, which affect chromosome number but not genome size, it can be impossible to distinguish if individual plants are polyploids in holocentric lineages based on chromosome count data alone. Furthermore, it is unclear how differences in genome size and ploidy levels relate to environmental correlates within holocentric lineages, such as the Cyperaceae.MethodsWe focus our analyses on tribe Schoeneae, and more specifically the southern African clade of Schoenus. We examine broad-scale patterns of genome size evolution in tribe Schoeneae and focus more intensely on determining the prevalence of polyploidy across the southern African Schoenus by inferring ploidy level with the program ChromEvol, as well as interpreting chromosome number and genome size data. We further investigate whether there are relationships between genome size/ploidy level and environmental variables across the nutrient-poor and summer-arid Cape biodiversity hotspot.Key resultsOur results show a large increase in genome size, but not chromosome number, within Schoenus compared to other species in tribe Schoeneae. Across Schoenus, there is a positive relationship between chromosome number and genome size, and our results suggest that polyploidy is a relatively common process throughout the southern African Schoenus. At the regional scale of the Cape, we show that polyploids are more often associated with drier locations that have more variation in precipitation between dry and wet months, but these results are sensitive to the classification of ploidy level.ConclusionsPolyploidy is relatively common in the southern African Schoenus, where a positive relationship is observed between chromosome number and genome size. Thus, there may be a high incidence of polyploidy in holocentric plants, whose cell division properties differ from monocentrics.

Dataset Information

Consistent phenological shifts in the making of a biodiversity hotspot: the Cape flora.

Background

Results

Conclusions

Publications

Consistent phenological shifts in the making of a biodiversity hotspot: the Cape flora.

Similar Datasets

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