LBI and Codfish Cooks petrel populations

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Neil Fitzgerald
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LBI and Codfish Cooks petrel populations

Postby Neil Fitzgerald » Thu Mar 25, 2010 10:07 pm

Matt J. Rayner, Colm J. F. Carraher, Mick N. Clout and Mark E. Hauber 2010. Mitochondrial DNA analysis reveals genetic structure in two New Zealand Cook’s petrel (Pterodroma cookii) populations. Conservation Genetics.

Abstract
The endangered Cook’s petrel (Pterodroma cookii) is restricted to two separated populations at the extremes of its former range across New Zealand. Prior work revealed morphological, foraging, and reproductive isolation between these two remnant populations. To aid the conservation management of the species, additional information is required on the genetic structure of Cook’s petrel. We used mitochondrial DNA sequences (Cytochrome Oxidase subunit 1 gene), collected from 26 and 19 Cook’s petrel breeding on Little Barrier Island (LBI) and Codfish Island (CDF), respectively, for this preliminary study. We uncovered distinct population genetic structure with analysis of molecular variance suggesting genetic isolation of the populations. Levels of genetic variation were higher in the LBI population (four haplotypes present; h = 0.34 and π = 0.10) whereas the CDF population had only one haplotype that was distinct from the LBI population. Our results indicate that Cook’s petrel constitute two distinct management units for which conservation of genetic as well as behavioural and morphological diversity should be a priority. Further genetic studies using nuclear markers are recommended.
THWorthy
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Re: LBI and Codfish Cooks petrel populations

Postby THWorthy » Sat Apr 10, 2010 3:04 pm

At the risk of seeming critical, these results are as expected. Clearly if all intermediate populations are removed (unnaturally) then a pair of distinct entities will be formed. Work on the ancient dna from all the now extinct intermediate populations of Cooks Petrels such as in Canterbury, NW Nelson, Taranaki etc would be expect to bridge the divide in exactly the same way as has been shown for example in kiwis. Perhaps instead of promulgating a human caused unnatural situation we should be mitigating it by translocatibng chicks from either relict population to the other and mixiung the genes once more !
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Graham Saunders
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Re: LBI and Codfish Cooks petrel populations

Postby Graham Saunders » Sat Apr 10, 2010 10:58 pm

Ah yes, but relying solely on the gene for cytochrome oxidase from the mitochondrial DNA can get one into problems; such as showing unequivocally that VOC and SIPO are the same species. There is a difference in this gene between the Hauturu and Codfish Island populations of Cook's Petrels, but this is merely one gene out of many, albeit one that mutates rapidly, hence it's use for DNA barcoding:

http://en.wikipedia.org/wiki/DNA_barcoding

"Barcoders also maintain that they are being dragged into long-standing debates over the definition of a species and that barcoding is less controversial when viewed primarily as a method of identification, not classification."
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Neil Fitzgerald
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Re: LBI and Codfish Cooks petrel populations

Postby Neil Fitzgerald » Mon Apr 12, 2010 11:38 am

Fair enough points Trevor, but given their strong breeding site fidelity and natal philopatry is it not likely that rather than a continuous cline there may have been a number of distinct types? If we hadn't stuffed things up so much, perhaps we would have Codfish Cook's, South Island Cook's, Nelson Cook's, Taranaki Cook's, Northern Cook's..?
As you noted in another topic, overzealous lumping can have a detrimental effect on conservation of populations, so is it not safer to treat them as distinct and equally important rather than homogenising them?
I'm a bit of a fan of cautionary eco-sourcing (assuming we probably know less than we think about many things).
Ian Southey
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Re: LBI and Codfish Cooks petrel populations

Postby Ian Southey » Thu Apr 15, 2010 10:56 pm

Finding genetic differences between these two poulations of cook's Petrel is interesting and it likely to be more than just the removal of intermediates. I understand recent records from geolocators show that the two populations of Cook's Petrel have totally different foraging areas http://nora.nerc.ac.uk/5855/ even though range should not limit them. Maybe these southern birds are the ones described by Murphy as subspecies orientalis. I'd say it was worth more than a casually critical look.

Ian
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Graham Saunders
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Re: LBI and Codfish Cooks petrel populations

Postby Graham Saunders » Fri Apr 16, 2010 11:33 pm

Ian Southey wrote: http://nora.nerc.ac.uk/5855/


And paid for by the British tax-payer. :?
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Re: LBI and Codfish Cooks petrel populations

Postby morepork » Fri Apr 16, 2010 11:47 pm

Glad to see some of my tax is spent on something useful.
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Neil Fitzgerald
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Re: LBI and Codfish Cooks petrel populations

Postby Neil Fitzgerald » Sat Apr 17, 2010 12:04 pm

Looks like an interesting paper thanks Ian. I'll try to get my hands on a full text.
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Graham Saunders
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Re: LBI and Codfish Cooks petrel populations

Postby Graham Saunders » Sun Apr 18, 2010 12:02 am

Is it just me that thinks of the People's Front of Judea when there are discussions like this?
Ian Southey
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Re: LBI and Codfish Cooks petrel populations

Postby Ian Southey » Mon Apr 19, 2010 7:58 pm

More like the Judean People's Front I think.

Ian

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