Wednesday, January 21, 2015

A trip of the past: the fossils talk to us about biogeography.

Insights of the PS3 Plenary Symposium Session on Saturday 10.01.2015

After a nice reception at the Botanical Garden which ended very late, the attendees congregated at the Auditorium of the University of Bayreuth next morning for the Plenary Symposium. During the session labelled: “Paleogeography: The importance of fossil data to species biogeography. Past, present and future”, the speakers Alicia Stigall, Thomas Servais, Wolfgang Kiessling, Thomas Denk, Andrea Sánchez and Catherine Badgley held presentations of a historical perspective of Biogeography.

To name some examples of the talks of this session, Stigall highlighted the difficulties of making biogeographical analyses with paleontological data. However, using an approach named Environmental niche modelling (ENM) is possible to incorporate into biogeographic inference the temporal, spatial, and environmental information provided by the fossil record, as a direct evidence of the extinct biodiversity fraction.

On the other hand, Andrea Sánchez explained some of the limitations of the fossil record: they represent a fraction of the living information of ancestral times, and therefore the biodiversity we see today is not representative of the historical one, especially after scenarios of high extinction. Her research team analysed the phylogenetic map of the Hypericum sp.  and they found out that it did not correspond with the fossil record.  They analysed the fossil data with a diversification–extinction–cladogenesis (DEC) model incorporating a model of the fossil reconstructions. As fossil record provides information of the location of the organisms, the climate as well as the ecological conditions of the environment of the previous times, dispersal patterns could be described. This allows to infer the past potential distribution and ecological corridors and barriers for dispersal.

Finally, Catherine Badgley explained a model of biotic responses to changes in earth history in terms of biogeographical processes. Specifically, tectonic changes and other environmental changes as change of sea level and climate change open and closes dispersal corridors for species. He explain three examples that portrait this scenario: in Miocene faunas of Pakistan and Spain, and in Quaternary faunas of South Africa. In these three examples of mammals’ biogeography, he concluded how the range of dispersal of these organisms was affected by climate change in accordance of the models applied.

by Yrneh Ulloa

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