The New Zealand Plant Conservation Network

..more discriminating markers than Wagstaff's work because she was looking at the idea of domestication in this species and her work does show a maximum diversity in Northland and indicates dispersal from there out to the rest of New Zealand, the Kermadecs and the Chathams. The Corynocarpaceae are a distinct Australasian lineage - and an oddity at that, which appears to show little genetic divergence hence its problematic position in the Angiosperm Phylogeny Classification. It is, as Brian Molloy showed clearly (but did not publish) their morphology that distinguishes them very well - and its the fruits and flowers that are the key. So my view is that C. laevigatus is endemic, and that the genus has been here since at least the late Miocene - and this accords with what we know of many of our indigenous plants - which appear here in the fossil record in the late Miocene / Pliocene.

Here endeth my views (amen) on LOL 'nativity' and I personally don't see any point in this being put into Trilepidea Astrid but if you wish to do so then I am happy to recast my prose - but it won't happen for a few weeks - Robyn Smith's initial comments fit with others issues namely whether this species is indigenous to the southern North Island, South, Chatham and Kermadec Islands, and whether we should view it as a 'weed'. Those are complex questions that are in part answered by the study of this species assumed domestication but also require further critical study of this species ecology, reputed allelopathy and so forth. I have yet to see a holistic study investigating those aspects, and I'd suggest that its long overdue and certainly worth doing - especially as a mythology has developed around this species because so little that we know about it has actually been published! I realize I am lucky as I have heard much of that unpublished work - but others haven't

I think we're going to have different points of view and until the necessary information is out there (from both sides) then it is difficult to make objective comment. The interesting thing is - if the endemic hypothesis is correct then why does the species show evidence of not fitting NZ's current ecosystems and why is it now becoming invasive in the southern parts of its range? And if the exotic hypothesis is correct, how did it get from the New Caledonia area to New Zealand. Maybe publishing the debate in Trilepedia would stimulate some people to provide their evidence, even if only as observations?

Indeed - but I still fail to grasp your statement 'evidence of not fitting NZ's current ecosystems' - what I and others have seen is that this species 'fits' nicely northern Northland and offshore Island 'ecosystems' where it is not invasive, except perhaps in those areas where possums have destroyed the likely natural competitors. As to why it is invasive south of its likely indigenous range, well aspects I touched on already, viz, allelopathy and the obvious fact that it is not indigenous to those areas explains that in much the same way as pohutukawa, karo taupata etc south of their natural ranges displace the 'natural ecosystems'. But again I believe I stated that I have yet to see a thorough, sensible ecological essay on this species - what I have seen has either focused on whether iwi domesticated it, or claims it was introduced to New Zealand from Raoul Island (rubbish) or from New Caledonia - which as I have already pointed out, is also rubbish because that is a different...

related species C. similis. For your hypothesis to be valid you would first have to satisfy people that C. similis and C. laevigatus is conspecific - which so far you have not. Then you would need to substantiate your claim that it is not 'fitting NZ's current ecosystems' - there you may have a point because as I said no one has properly examined its ecology...But a study ignoring one facet in favour of the other is not sensible. Further you have ignored my statements about the genus and family and DNA data used to date - as I said those studies will not support your views because the markers used were not the right ones to answer that sort of question. Robyn's data does offer some ways of answering your questions - but until she formally publishes that data it is her business not mind. Ciao

Astrid,
I agree you should put in the Trilepidea.
At 25 replies and counting it has certainly stimulated some great debate. Even to the layman a discussion like this sounds quite interesting. Also very informative. o please publish :)

Not entirely relevant but I thought I would spice things up since the conversation is getting interesting.....here is a picture I drew of the Karaka :)

And a very nice picture it is too!

I think it is worthwhile airing both sides of an argument - it stimulates people to think about an issue and the wider applications too. Much like the Hebe/Veronica debate (where Peter and I are both on the same side!).

The "evidence" (mostly unpublished as yet for not fitting NZ ecosystem:
1) NZ pigeon only disperser for this species, and likely to have been this case for at least the Holocene, but NZ pigeon seems to view (anthropomorphising I know) karaka as a famine food as it rarely feeds on it despite the massive fruiting display and eats smaller fruits when it does. IF endemic would have expected coevolution to drive towards either tastier fruit or smaller fruit.

2) The regeneration pattern of karaka on northern offshore islands is no different whether NZ pigeon present or not (contrasting greatly with regeneration patterns for species likely tawa, taraire, coastal maire, tawapou, puriri).

......

....

3) on mainland NZ (and elsewhere) I think the dense carpet of seedlings you find under adult karaka is very different to that you find under other large-fruited tree species and is indicative of a species behaving invasively but being hindered by a lack of dispersal of seed.

The evidence I have seen that it is endemic are Wagstaff and Dawson's 2000 paper who tested only one C. dissimilis sample and do note genetic differences between C. laevigata and C. dissimilis samples. I argue that this study was not of enough samples to show that the two species are not conspecific.

The Miocene leaf fossil I argue is not evidence for continuous occupation of NZ by Corynocarpaceae as it is possible that there was a species inhabiting the very different climate of NZ at that time which became extinct when climate cooled and vegetation changed.

Molloys 1990 conference proceedings note the difference in fruit size. I argue the smaller fruit of C. laevigata in NZ is a result of the co