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Title: Macroevolutionary history of Neotropical vegetation during the Cenozoic : a palynological perspective from Colombia
Author: Bonilla, German Felipe De La Parra
ISNI:       0000 0004 7654 6894
Awarding Body: University of Oxford
Current Institution: University of Oxford
Date of Award: 2019
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The Neotropics are the most plant species-rich realm of the Earth. This surprising megadiversity has been studied since times of Darwin and Humboldt, with different mechanisms proposed, not only to explain how such great diversity was produced but also how it is maintained. This system is not completely understood, and will continue being matter of study for a long time. Knowledge of the deep time patterns of diversity and diversification are central to testing hypothesised mechanisms. But the patterns have received much less attention than have the mechanisms proposed to explain them. In this thesis I used an extensive palynological record of Colombia to study the macroevolutionary history of Neotropical vegetation and its relationship with regional and global process occurring during the Cenozoic. The results show a strong correlation between fluctuations in palynological diversity and global changes in temperature. Contrasting responses of vegetation to temperature between the Palaeocene to Eocene and the Oligocene to Present suggest that different mechanisms operated during greenhouse and icehouse intervals. Throughout the Cenozoic, periods of elevated extinction are followed by periods of high origination. This relationship suggests that in the Neotropics when a species become extinct, it is replaced very fast. In contrast, the lack of correlation between origination and extinction suggest that extinction is not controlled by origination. The examination of the taxonomic rates and the global climatic curve indicate a good correspondence between episodes of global climate change and turnover, suggesting that extinction is exacerbated by these episodes. Finally, the palynological record also indicates that the Neotropics experienced several floods during the Cenozoic. These episodes include marine incursions, the development of extensive lacustrine systems and the establishment of mangrove forests. The relationship between floods and the evolution of Neotropical vegetation is challenging due to the uncertainty related to the temporal and geographic range of the floods. The evidence suggest that the floods had a local rather that a regional effect on the evolution of Neotropical vegetation.
Supervisor: Benson, Roger Sponsor: ECOPETROL
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Macroevolution ; Biostratigraphy