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The Sunda-Sahul exchange: history and biogeographic patterns

The role of biogeographic history in current species distribution patterns are of interest to many scientists.

Understanding the biogeographic patterns of Australian rainforest flora is important as the flora comprise of two groups of contrasting histories: those of recent Sunda (southeastern Asian) ancestry and those of Sahul (Gondwanan) ancestry. As such it is important to acknowledge the role of biogeographic history and ecological processes that shape Australian rainforest communities.

 An interesting approach is to employ population genetics of co-distributed species to observe if their landscape-level dynamics responded to similar historical events. Incongruent patterns can occur due to different responses to geographic barriers or founder events, congruent patterns can come about in response to the effects of the Quaternary climate oscillations. 
 
To date, a population genetics study of co-distributed Australian rainforest species in subtropical Northern NSW has shown that rapidly expanding Sunda lineages have relatively lower genetic diversity than Sahul lineages. Following these results, a study in the Australian Wet Tropics provided the opportunity to observe how contrasting histories influence the way diversity is distributed and how populations are structured across a broader geographical range (spanning both tropics and subtropics).

Current research

We are analyzing the chloroplast genome data from 90 species from multiple sites to improve our understanding of how current and historical rainforest communities assemble. The findings of this study will direct our search for processes that maintains diversity in these recent expanding lineages, as well as understand the areas in which Sunda and Sahul lineages co-exist 

Some of our relevant publications:

  1. Yap JYS, Rossetto M, Costion C, Crayn D, Kooyman R, Richardson J, Henry R (2017) Filters of floristic exchange: how traits and climate shape the invasion of Sahul from Sunda. Journal of Biogeography
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