birding-aus

Ring-a-Ring-a-Rosella

To: "'L&L Knight'" <>, "'Birding Aus'" <>
Subject: Ring-a-Ring-a-Rosella
From: "Tony Russell" <>
Date: Wed, 30 Jul 2008 16:14:36 +0930
Well, that's interesting, but I'm sticking to Platycercus elegans,
nigrescens, flaveolus, subadelaidae, fleuriensis, and melanoptera for
the time being.

When you look at them you can see they are all different.  Finito.

Tony.

-----Original Message-----
From: 
 On Behalf Of L&L Knight
Sent: Wednesday, July 30, 2008 4:05 PM
To: Birding Aus
Subject: Ring-a-Ring-a-Rosella


The following item is almost hot off the press ...

Regards, Laurie

http://www.csiro.au/news/CrimsonRosella.html

Rosella research could re-write 'ring theory'

Reference: 08/128

New research has uncovered how different crimson rosella populations  
are related to each other - a discovery which has important  
implications for research into how climate change may affect  
Australia's biodiversity.

30 July 2008

Published today in the prestigious journal Proceedings of the Royal  
Society B, the research investigates the genetic and geographical  
relationships between different forms of crimson rosellas and the  
possible ways that these forms may have arisen.

Dr Gaynor Dolman of CSIRO's Australian National Wildlife Collection  
says there are three main colour 'forms' of the crimson rosella -  
crimson, yellow and orange - which originated from the same ancestral  
population and are now distributed throughout south eastern Australia.

"Many evolutionary biologists have argued that the different forms of  
crimson rosellas arose, or speciated, through 'ring speciation'," she  
says.

The ring speciation hypothesis predicts that a species that spreads to  
new areas may eventually join back up with itself, forming a ring. By  
that time, the populations at the join in the ring may be two distinct  
species and unable to interbreed, despite continuous gene flow, or  
interbreeding, between populations around the ring.

"We found that in the case of crimson rosellas, their three separate  
genetic groups don't show a simple link to the geographical  
distribution of the colour forms," Dr Dolman says.

"For example, orange Adelaide and crimson Kangaroo Island rosellas are  
separated by 15km of ocean but are genetically similar. Conversely,  
genetic dissimilarity was found in the geographically linked yellow  
and orange populations in inland south eastern Australia.

"We found that in the case of crimson rosellas, their three separate  
genetic groups don't show a simple link to the geographical  
distribution of the colour forms," Dr Dolman says.

"We rejected the ring hypothesis because it predicts only one region  
of genetic dissimilarity, which should occur at the geographical  
location of the join in the ring, around the headwaters of the Murray  
and Murrumbidgee Rivers.

"However, it is possible that crimson rosellas formed a ring at some  
stage in their evolutionary history, but that the evidence has been  
lost through climatic or environmental changes," she says.

Wildlife genetic research of this kind is increasing our understanding  
of the biogeography and evolution of Australia's terrestrial  
vertebrates, helping Australia sustainably manage its biodiversity and  
ecosystem functions in the face of land use and climate
change.==========www.birding-aus.org
birding-aus.blogspot.com

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