14. Australian evolutionary radiations

First meeting 1-2 August 2006, in Hobart Second meeting was held 27 November - 1 December 2006 in Hobart

PARTICIPANTS Leader David Bowman, University of Tasmania Barry Brook, Charles Darwin University Les Christidis, Australian Museum Peter Baxter, U Queensland David Morris, ANU Chris Johnson, James Cook U Pauline Ladiges, Melbourne U Janette Norman, Museum of Victoria Brad Potts, U Tasmania Kale Sniderman, Monash U Matt McGlone, Landcare Research NZ Greg Jordan, U Tasmania Dorothy Steane, U Tasmania Cam Webb, Harvard U Mark Westoby, Macquarie U Grant Williamson, Charles Darwin University

This working group is being supported jointly between the Network for Vegetation Function and the Environmental Futures Network.

Meeting 1
An initial 2-day meeting 1-2 August 2006 focused on eucalypts and on birds, two important clades in Australia where phylogenetic trees have advanced recently. Following on from this, further smaller meetings are envisaged.

1. Analysis of the spatial congruence of bird radiations, plus lineages-through-time analysis of diversification in birds and other vertebrates. Data assembly is already underway, with involvement of Janette Norman, Les Christidis, Chris Johnson, Barry Brook, Brendan Mackey and David Bowman. There will be a meeting of this group in Hobart in late November/early December 2006. Results will be reported back to the wider group.

2. If the meeting about birds is successful, Bowman will canvas interest for another meeting looking at eucalypt radiations possibly using a similar analytical approach as we propose to use for the bird phylogenetic/spatial data.

3. A meeting revisiting the options for molecular clocks and fossil calibrations for birds and eucalypts. Ideally this will be in the context of the success of the spatial analyses in Stages 1 and 2 above, but it can possibly stand alone if these analyses don't work out.

Meeting 2
A second meeting 27 Nov - 1 Dec 2006 in Hobart included Norman, Brook, Mackey, Christidis, Williamson and Bowman. Detailed analysis of a particular dataset was undertaken. Initially these results have been presented at the Southern Connections conference in Adelaide at end-January 2007.

Background
The long-term aim of this working group is to develop the historical and ecological narrative of Australian evolutionary radiations, and especially, to ask what features different radiations have had in common.

Improved molecular phylogenies continue to emerge for many clades. Our aim is to ensure that some supplementary tools and imformation become available with each of these, including:
1. Best current methods to put confidence intervals on the estimated dates for each evolutionary divergence. This includes integrating fossil information into the dating algorithms.
2. Collecting some simple ecological traits for present-day species, such as leaf mass per area, ramification and branching angle, wood density, leaf toothing, seed size and so forth.
3. Quantification of the climate envelopes and soil types occupied by present-day species.
4. Software tools for expressing phylogenetic trees as evolutionary divergences in ecological traits or environmental envelopes.
5. Best available information about the physical environment at different dates and places during the geological history of the radiation.

Given these supplementary tools and information, we can ask questions about the nature of the radiation in each clade. For example, questions about the sequence: have clades usually diversified across soil types first, and subsequently in the stature and ramification of the plant or in floral traits or along rainfall gradients?

And the eventual aim is to ask how consistent these patterns are across different clades. Is the sequence, and even the geological timing, similar across many clades? Or does each clade have a distinct and idiosyncratic ecological history?

Last updated January 2007