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Re: Discussion and plight of NZs subspecies

Posted: Mon Jun 01, 2020 9:14 am
by MKOVERY
Surely how long Evolution takes to change a subspecies to a species should be measured in generations, rather than years?
Homo sapiens has a breeding age of say 20 years, then 100 years is just five generations - i.e. five evolutionary mutations.
A Blackbird has a breeding age of one year, so 100 years is 100 generations (mutations) - 20 times as rapid!
It can take relatively few generations for a distinct evolutionary adaptation to be evident.

For anyone who hasn't read it I recommend Jonathan Weiner's "The Beak of the Finch", all about Peter Grant's study of the Galapagos Finches - Grant demonstrated that quantifiable evolutionary changes can occur in just a couple of generations, given the right conditions.

Given that the current taxonomic ideology is for 'splitting' rather than 'lumping', that would suggest that all of New Zealand's subspecies could be considered endemics species.

Re: Discussion and plight of NZs subspecies

Posted: Mon Jun 01, 2020 11:17 am
by Jim_j
Thanks Simon - hadn't expected such an easy answer..!
I hadn't realised all the non-protected species were actually listed - must have a look at the schedule just to see who these bad boys are.

Cheers
Jim

Re: Discussion and plight of NZs subspecies

Posted: Mon Jun 01, 2020 11:46 am
by Oscar Thomas
There are a lot of assumptions and sentences starting with 'I think..' being made in this thread. If anyone can provide references to SI Kokako having blue wattles, NI Kokako with orange ones, and a record of a NI Kokako in the Marlborough Sounds I'd be interested to see them. The two species were a lot more different than just the colour of their wattles.

Re: Discussion and plight of NZs subspecies

Posted: Mon Jun 01, 2020 3:03 pm
by Jim_j
Hi Oscar

My "I think" was the Marlborough Sounds report - I'm pretty sure (sorry) it was in one of the Rare Birds reports in Notornis - when I have a spare minute I'll update with the detail - should be pretty easy to find I hope - "think" it was around the time DoC updated the SI Kokako from extinct to Data Deficent.

cheers
jim

Re: Discussion and plight of NZs subspecies

Posted: Mon Jun 01, 2020 3:49 pm
by simon.fordham
Oscar Thomas wrote:If anyone can provide references to SI Kokako having blue wattles, NI Kokako with orange ones....


NZ Birds online make mention of NI birds with orange wattles. I was interested to read that the SI birds had blue at the base of the orange wattles.

Cheers
Simon

Re: Discussion and plight of NZs subspecies

Posted: Mon Jun 01, 2020 4:33 pm
by Jim_j
The Marlborough Sounds sighting of a kokako was not accepted by the RAC but the comment made was that it was more likely to be a NI Kokako - not sure on what basis that was - Notornis 2013 Vol 60 2013/01J.

The article on SI kokako in Vol 61 also makes reference to variable wattle colour with references to the source publications.


Cheers
Jim

Re: Discussion and plight of NZs subspecies

Posted: Tue Jun 02, 2020 2:29 pm
by fras444
Haha, you stole my idea on a future discussion on our exotic species and how far along they have come regards the 100 odd years of separation. Very interesting thoughts on how many generations of Blackbirds and the like here in NZ and what changes if any, at this point of time do they posses.... Got to throw in the cattle and sheep and their physical adaptations on the Auckland Islands.... Great example of a case study on adaptation in such a small period of time... Rats on the other hand... Because they are not a massive mammal, their physical adaption to the Auckland Islands was all but nil due to their size etc..

But the exotic birds.... How much adaptations have they gone through over the last 100 years and have they adapted to native environment outside the urban and hort environment and have they become a positive impact in regards to pollination and seed dispersal to our native plants etc...

Re: Discussion and plight of NZs subspecies

Posted: Tue Jun 02, 2020 7:45 pm
by Oscar Thomas
Cheers Jim and Simon, interesting stuff.

Here's some info about how little Yellowhammer calls have changed over the last 150 years:
https://www.nzherald.co.nz/nz/news/arti ... d=11782717

Re: Discussion and plight of NZs subspecies

Posted: Wed Jun 03, 2020 9:06 am
by Neil Fitzgerald
This discussion of introduced birds could be applied to introduced mammals. Some people regularly do this already, but I think (hope) most people understand that just because something has been here for a hundred years does not mean that it has reached any sort of 'natural balance' or is now sufficiently unique that we should sacrifice native biodiversity for it.

Re: Discussion and plight of NZs subspecies

Posted: Wed Jun 03, 2020 10:03 am
by Jim_j
Yes good point - if only that was the case - I personally have no issue with introduced mammals in NZ as such - unfortunately it doesn't look like we can have both.
I read that possums would eventually turn NZ into a grassland - apparently even trees that are unpalatable or poisonous to them now their stomachs will adapt to over time.

Maybe If our trees and plants didn't have masting cycles maybe rats & mice might reach a balance? - likewise if we had no rats, mice, rabbits etc then maybe mustelids would eventually reach a balance (although perhaps endemics/natives would just reduce at a slower rate as they still have exotic birds as an alternative food source)?
But we'd still probably loose saddleback, kokako etc with even very low predator numbers

I'm not sure if any exotic birds have a similar effect - the studies seem to indicate that in a native forest habitat at least natives tend to dominate?
I guess maybe the old favourite the mallard is the closest - but I suspect if we restored the habitat and removed the predators there might be less of an issue

cheers
jim