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Author elsslots
Admin
#31 | Posted: 13 Jul 2019 05:31 
For the natural part of Paraty I'd go for the same as we already have for Atlantic Forests South-East: Paleocene. But there's nothing about its age in the AB ev,

Author elsslots
Admin
#32 | Posted: 13 Jul 2019 05:32 
And finally: the Migratory Bird Sanctuaries near the Yellow Sea.
The most difficult one probably, nothing in the AB ev. The similar Wadden Sea is very young, this might be as well.

Author Solivagant
Partaker
#33 | Posted: 13 Jul 2019 05:58 | Edited by: Solivagant 
elsslots:
And finally: the Migratory Bird Sanctuaries near the Yellow Sea.
The most difficult one probably, nothing in the AB ev. The similar Wadden Sea is very young, this might be as well.

One of my take-aways from the "exercise" of doing the Time line for Natural sites is the realisation of just how many of them acquired the values we now place upon them relatively recently - i.e Holocene - within the last 11600yrs. Vatnajokull is a fine example of that. Indeed, I suspect that we have given earlier periods to too many of them!! The Earth has been a continuously changing place even in recent "geological time" and it is perhaps too easy to assume that the "natural"aspects we see today have been unchanging for aeons - when they have not,

Bird migration as currently existing is relatively recent too - depending on both the current location of continents and shorelines together with the general post-glacial climate distribution. This comment on bird migration in Wiki is relevant "Migration in birds is highly labile and is believed to have developed independently in many avian lineages. While it is agreed that the behavioural and physiological adaptations necessary for migration are under genetic control, some authors have argued that no genetic change is necessary for migratory behaviour to develop in a sedentary species because the genetic framework for migratory behaviour exists in nearly all avian lineages. This explains the rapid appearance of migratory behaviour after the most recent glacial maximum".

The Yellow Sea itself is shallow and relatively recently formed - "Scientists believe that the sea was formed during the last Ice Age near about 10,000 years BP (Before Present). During the Ice Age, sea levels rose dramatically and a section of the continental shelf where Yellow Sea sits today, was flooded by rising sea levels."

Undoubtedly - Holocene
Before then the birds would have gone somewhere else - or maybe nowhere at all!!!

Author elsslots
Admin
#34 | Posted: 13 Jul 2019 06:20 
Good! What's your opinion about the penguins & the French Austral Lands?

Author Solivagant
Partaker
#35 | Posted: 13 Jul 2019 06:44 
elsslots:
What's your opinion about the penguins & the French Austral Lands?

OK -the islands and penguins have both existed for millions of years but - when did the "Penguins" first start using the islands??? It really needs both in place to give the value (Penguins of course are a proxy for the entire range of wildlife). Did the Antarctic have glacial periods as well or is its history in relation to such matters completely different from the Arctic - as of course is its geology. I will have a search

Author Solivagant
Partaker
#36 | Posted: 13 Jul 2019 07:28 | Edited by: Solivagant 
elsslots:
The French Austral Lands:
- The Kerguelen Islands started to appear 35 million years ago (wiki)
- Penguins were already around on the earth 50 million years ago
So go for Eocene? Nearby Heard & McDonald islands we also have at that.

Early investigations suggest that is a bit early
a. The Geology - Whilst it is true that the Islands seems to have appeared from c 39mya ("Million years ago"). The suggestion is that they remained unstable and volcanic long after that - "the main part of the lava cropping out in these islands erupted in a relatively short period that has a well-established age (Lower Miocene - i.e "early")
b The Fauna (espec Penguins) - This article, rather nicely titled "Penguin Past", concludes that, whilst proto-penguins appeared from before 50mya), the development of extant species was rather later - "In their opinion, cooling provided speciation opportunities to colonize an extreme environment, and this probably happened recently. Clarke et al. (2007) suggested the Miocene epoch for the common ancestry of the present−day genera. Unlike Baker et al. (2006), they (Ksepka et al. 2006) emphasize the importance of Subantarctic regions for penguin evolution, and locate the common ancestry of all the extant genera in the Antarctic Peninsula, the Scotia Arc and New Zealand"

The periods we are looking at are
Paleocene 66-56 Mya
Eocene- 55-33 Mya
Oligocene- 33- 23 Mya
Miocene- 23-5.33 Mya
Pliocene - 5-33-2.5 Mya

As yet I can find nothing more specific re Kerguelen but it would seem that the earliest period in which extant penguin species could have colonised a stable Kerguelen would have been Miocene? (We don't need to go into whether Early/Middle or Late!) Whether this argument applies to Heard etc as well I don't know. I haven't been able to discover any suggestion that the Kerguelen Islands might have undergone major changes more recently - but that doesn't mean they didn't!

Author elsslots
Admin
#37 | Posted: 13 Jul 2019 23:59 
Solivagant:
I haven't been able to discover any suggestion that the Kerguelen Islands might have undergone major changes more recently - but that doesn't mean they didn't!

I have gone for Miocene now. Maybe we will learn more when the nomination file is available.

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