Presentation by Rosane G. Collevatti at the 2013 GBIF Science Symposium. Title: Coupling paleodistribution modelling and statistical phylogeography to trace the history of Neotropical savannas and seasonally dry forests.
Recurrent climate oscillations throughout the Quaternary Period raise general questions about the long-term stability and dynamics of vegetation communities and the role of past climate change on their current patterns of genetic diversity and geographical distribution. Currently, coalescent analyses has been coupled with ecological niche modelling (ENM), for which the GBIF and PMIP/CMIP databases were extensively used, to trace the demographical history of tree species from Neotropical savannas and seasonally dry forests (SDFs) and to test hypotheses concerning their dynamics in response to Quaternary climate oscillations. The study’s analyses follow the framework recently proposed by Collevatti et al. (2012), which, in sum, is based on coalescent simulations performed under demographic expectations from a priori biogeographical distribution hypotheses and potentially new hypotheses suggested by ENMs. The results from competing simulations are compared using a model selection framework. The study results showed different demographical dynamics for species from SDFs and savannas through time. The current pattern of genetic diversity found so far for SDF species is in consonance with a scenario of demographical expansion, whereas savanna species showed range retraction during the Last Glacial Maximum (LGM), leading to multiple refugia.
Rosane G. Collevatti