World Heritage Site

for World Heritage Travellers



Forum: Start | Profile | Search |         Website: Start | The List | Community |
Connections www.worldheritagesite.org Forum / Connections /  
 

Timelines

 
 
Page  Page 6 of 7:  « Previous  1  2  3  4  5  6  7  Next »

Author Solivagant
Partaker
#76 | Posted: 5 Mar 2015 13:52 
elsslots:
I still see them (scroll to the right)

I have "fully scrolled"!!
Whether it is Waterfox - I will try Chrome

Author Solivagant
Partaker
#77 | Posted: 5 Mar 2015 13:58 | Edited by: Solivagant 
Solivagant:
Whether it is Waterfox - I will try Chrome


Very strange - it is ok in Chrome with 19th C as fully scrolled right (with 20th C below it) but fully scrolls right in Waterfox as on my PC (the latest version) with "Full scroll" reached after the 16th C

Author elsslots
Admin
#78 | Posted: 5 Aug 2021 14:26 
Can I get some help with the last remaining Timelines to be added to the new WHS? As always the natural sites are giving me trouble.

Ivindo (criterion ix and x) - Holocene (from 11,700 years ago)?
- "very old Caesalpinioideae climax forest on about 30-40% of its area", Guineo-Congolian forests -> "While there is strong evidence that there were forests all over the area as far back as 1.6 million years ago, the current tropical forests emerged about 10,000 years ago, following the last Ice Age." (source)
- flagship animals like the forest elephant and lowland gorilla (gorillas and chimps evolved 5-8 million years ago)

Kaeng Krachan (criterion x) Holocene?
- high number of globally threatened wildlife species such as the siamese crocodile.

Author Solivagant
Partaker
#79 | Posted: 6 Aug 2021 05:53 | Edited by: Solivagant 
elsslots:
Can I get some help with the last remaining Timelines to be added to the new WHS? As always the natural sites are giving me trouble.

As an aside I went to look at how we had assigned a timeline to the other 2 Natural forest sites from Thailand - Thungyai-Huai Kha Khaeng and Dong Phayayen-Khao Yai ..........and, as far as I can see, we haven't!! I did a few other checks and I think that there are more WHS (probably all of which are Natural sites) without an assigned Timeline. Could you produce a list?

To the problem at hand. Unfortunately we never seem to have attracted a Geologist or similar to our Community and have therefore had to rely on our own somewhat less than significant "knowledge" of the subject area! We did our best to develop criteria and guidelines for assigning Timeline periods but I suspect that the assignments we made wouldn't always stand up to critical evaluation. Natural sites created their own particular problems. As I remember it we tried to assign on the basis of when the claimed OUV arose rather than on when the entire site as currently existing. (Let alone its earliest aspect) was formed. So - a geological site got assigned to the relevant geological period which created its main OUV rather than to the period of its current flora and fauna. A site whose OUV is based on a particular species was assigned to the period of evolution of the species in that area or its arrival there. Many "flora and fauna" sites are of course inscribed on a "package" of aspects which make up their current OUV - geology, endemism, current ecology etc etc. The norm will be that such sites will get assigned to the Holocene period unless there is a good reason to choose an earlier one (e.g because of "Relict" ecosytems , "Island endemism)" or similar). The ecology of most places on earth has undergone significant change even across the Holocene's c11700 ybp since the Pleistocene's 2,580,000 to 11,700 ybp. A natural site inscribed for "what it is today" was most likely "created"/emerged within the Holocene period - and might well have undergone significant changes even across that relatively short (in Geological terms) timescale!
Where we felt that the OUV predated the Holocene we have tried to divide the Pleistocene "Glacial period" into the Early (2.58m- 770,000ybp), Middle (770,000-126,000ybp) and Late/Upper (126,000 -11,700ybp). Scanning through them we have done so largely in the case of Hominid, and Volcanic sites together with some relating to faunal "migrations" and "dateable" erosional/minor tectonic changes to landforms.

So to the 2 WHS in question based on the above guidleines
KKFC.
See this paper on the effects of Glaciation on the Malay peninsula and forestation. It generally concludes that during this period the lower sea levels and emergence of "Sundaland" meant the land was far more "savannah like" than today.
There is also this, unfortunately difficult to read, presentation on the emergence of the Khao yai geology and landscape which identifies almost the entire geological history of the World as having contributed (!) but really shows that the Holocene climate has created both thr flora/fauna mix and the landscape.
From these. and our "guidelines" as above, I would judge that all 3 Thai Natural WHS are "Holocene" in the sense that they required the post glacial climatic changes to create the "rain forest" and the erosion etc which characterises the landscape.

Ivindo
Ivindo is situated around 200kms east of Lopé-Okanda WHS within the same Ogooue River basin. We should at least take into account our timeline assessment of one to inform the other! Lopé-Okanda however is a Mixed WHS and has been assigned to Middle Pleistoicene on the basis of its "400,000 years of almost continuous history". We have normally identified both a natural and a cultural timeline period for mixed sites. The Ivindo nomination file goes to some lengths to try to differentiate it from Lopé-Okanda - but the main difference seems to be that Ivando is "all forest" whilst Lope is mixed Savannah and Forest. In fact the ICOMOS evaluation shows that the majority of the Cultural aspects are Neolithic and Iron Age - the Middle Stone age isn't represented and even the Early Stone Age is only "thinly" referred to . There is however a significant relationship to the "Middle Holocene Bantu Migrations" (3,500-2,000 BP) which were eased by following the Savannahs rather than the forests.

I found this article re the emergence of the Congo Forests
"There is strong evidence that forest cover was reduced during the last Ice Age, lasting from 1.6 million to 10,000 years ago. While forested areas in the Congo River Basin are known to have persisted in some areas called refugia..........About 10,000 years ago, as the last Ice Age ended, glaciers receded and rainfall increased. The changing climate allowed savannas to be reclaimed by trees, and the forest grew to reach its current size."
The article also refers to the complexities of the climate changes during the Holocene which resulted in an ebb and flow of the "Savannah/Forest mosaic".
Those changes to the Congo forests during the Holocene are also referred to in this article

In summary I would judge that both Ivindo AND Lope should be assigned to the Holocene Time periods. In the case of the latter the Cultural Time period should be Neolithic - 4th Millenium BC as being the majority "cultural" aspect.
Of course there were forests in the wider Congo basin pre Pleistocene... the Congo Forest article mentions Late Miocene (11.63 - 5.333 Mybp). These were no doubt "important" within a lengthy evolutionary timescale.....but they underwent many many changes even if much of the flora and fauna surived somewhere - to extend and bounce back later. Re Ivindo, bear in mind also that a major feature of it is the Langoué Baï ("one of the 5 most important forest clearings in Central Africa" Wiki) - which must be relatively "recent" in geological terms

Author elsslots
Admin
#80 | Posted: 6 Aug 2021 12:02 | Edited by: elsslots 
Solivagant:
There is also this, unfortunately difficult to read, presentation on the emergence of the Khao yai geology and landscape which identifies almost the entire geological history of the World as having contributed (!) but really shows that the Holocene climate has created both thr flora/fauna mix and the landscape.

They could have used a more readable font indeed, but it is an interesting background story. I'll put a link up.

Solivagant:
Could you produce a list?

The list comes out as follows:
Thungyai-Huai Kha Khaeng (see above)
Yakushima
Sinharaja Forest
Taï National Park
Comoé National Park
Central Suriname Nature Reserve
Dja Faunal Reserve
Manovo-Gounda St. Floris
Bwindi Impenetrable National Park
Ichkeul National Park
Niokolo-Koba National Park
W-Arly-Pendjari Complex
Manu National Park
Serengeti
Selous Game Reserve
Western Caucasus
Virgin Komi Forests
Cerrado Protected Areas
Central Sikhote-Alin
Tropical Rainforest Sumatra
Dong Phayayen (see above)
Central Highlands
Sangha Trinational
Mount Hamiguitan
Great Himalayan National Park
Kaeng Krachan Forest (see above)
Los Alerces National Park
Qinghai Hoh Xil
Tarnowskie Góry Lead-Silver Mine
Landscapes of Dauria
Hebron/Al-Khalil Old Town
Ivindo National Park (see above)

The 2 cultural ones (Tarnowskie Gory and Hebron) I'll manage I guess.
I wonder if the Latin American and Russian (rain)forest sites have much different timelines from the Asian and Central African ones as determined above.

Author elsslots
Admin
#81 | Posted: 7 Aug 2021 01:25 
Solivagant:
There is however a significant relationship to the "Middle Holocene Bantu Migrations" (3,500-2,000 BP) which were eased by following the Savannahs rather than the forests.

If we see this as the defining moment, this makes it 2nd mil BC instead of 4th?

Author Solivagant
Partaker
#82 | Posted: 7 Aug 2021 01:56 
elsslots:
If we see this as the defining moment, this makes it 2nd mil BC instead of 4th

Yes..!

Author Solivagant
Partaker
#83 | Posted: 7 Aug 2021 03:58 
Suggest
Sinharaja- Miocene
Ecological separation from India in the late Miocene. The OUV emphasises the endemism this arisingSee
https://www.oneearth.org/ecoregions/sri-lanka-lowland-rainforests/

Author elsslots
Admin
#84 | Posted: 7 Aug 2021 10:06 | Edited by: elsslots 
elsslots:
Ichkeul National Park

As a migratory birds site inscribed on criterion X only, I think we can safely assign Holocene to this one as well

Author Solivagant
Partaker
#85 | Posted: 7 Aug 2021 11:40 | Edited by: Solivagant 
Bwindi - Late Pleistocene
"most of nowadays forests are not further than 12,000 years old, Bwindi's vegetation has been weaving itself into tangles over 25,000 years.... Bwindi acted as Pleistocene refugium and it was able to protect the jungle during the ice age when Africa didn't have such dense vegetation cover. It served as a water tower for most of the wildlife species that relied on the forest unlike other areas that didn't have any forest or vegetation cover"
https://www.bwindiimpenetrablenationalpark.com/information/vegetation/

I think this also further justifies the decisions on e.g Ivindo. I think we can assign Dja to Holocene on the same basis

Author Solivagant
Partaker
#86 | Posted: 8 Aug 2021 03:19 
Central Highlands - Miocene
Same argument as for Sinharaja-
Here is specific link
https://www.oneearth.org/ecoregions/sri-lanka-montane-rainforests/

Author Solivagant
Partaker
#87 | Posted: 10 Aug 2021 05:17 | Edited by: Solivagant 
Since 5 of the missing Natural timelines are from S America (Central Surinam, Cerrado, Manu, Los Alerces and Chiribiquete (which only has a cultural timeline date), I have been trying first to gain an understanding of the broad sweep of S American geological events before homing on the specifics.
This has led me to question a few of the existing timeline assignments -
Canaima NP.
Has been assigned to the earliest period of any of the S American WHS - "Proterozoic: The oldest rocks are Precambrian and, around 1700 million years old, are some of the oldest on the planet (crit vii)". This is true - but the defining feature of Canaima lies in its Tepuis and the "island evolution" which they have enabled - "The tepuis constitute a unique biogeological entity and are of great geological interest. The sheer cliffs and waterfalls, including the world's highest (1,000 m), form a spectacular landscape." (OUV Summary). Without the Tepuis any timeline period would seem to present an incomplete picture.

The Tepuis (and associated features such as sinkholes and caves) are the remains of an eroded Sandstone/Quartz plateau from c1.7mybp which overlays even earlier "Granitic basement". This forms part of the Guiana Shield. Its formation took many hundreds of millions of years to lay down and much of the original sandstone has become metamorphised into harder quartz. This long predated the splitting of S America from Gondwana, opening up of the Atlantic etc etc (180mybp). Unusually, these ancient rocks have not since undergone any major tectonic event to contort them – hence their plateau form.

The question would seem to be - when did that plateau get eroded into a form similar to that existing today thus permitting the biological evolutionary processes which, together with the landscape, form part of the OUV?

As far as I can make out this question is still not fully answered by science! The WWF web site states "Following the uplifting of this once-continuous layer, subsequent erosion resulted in the separation and isolation of the Tepui Mountains, approximately 180 million years ago." (i.e Jurassic 201-145mybp). Wiki doesn't commit itself - "Throughout the course of the history of Earth, the plateau was eroded, and the tepuis were formed from the remaining monadnocks." A more frequently expressed view is that it "started" around 100-80 mybp (Cretacious 146-66mybp) possibly arising from the changes after the Gondwana break up to weather patterns, associated uplifting and rifting etc etc. But the rate of erosion and the point at which it became significant in evolutionary terms isn't clear - The hardness of the quartz seems to make comparison with erosion rates elsewhere difficult. This academic article describes it as a "Cretaceous-Paleocene" erosion (ie 145-56 mybp).

Another article states "Since... quartz dissolution requires a long time, the recent landscape, including commencement of the cave-forming process, is considered to be inherited from the Mesozoic period (i.e Cretaceous)"

Even the evolutionary impact of the erosion is under debate - did the changes occur to species left behind "on the summits" or much later via various forms of dispersion (including mountain climbing frogs!). This article concludes that most speciation took place during the Pliocene (5.3 to 2.5 mybp)

Another assessment (which is something of an outlier) is that the current landscape might have arisen as late as c20mybp (Miocene).

Clearly the erosion has continued since it first started through to today so the main point is to identify its "significant" commencement if there is no other "major period" to home in on.

IMO it would seem best to assign it to Cretaceous – which itself covers 135-60 my so gives some scope for error! As "reasoning" I would suggest -
"The erosion of the Cambrian Sandstone/Quartz plateau which resulted in the current Tepui landscape and led to its "island" evolutionary aspects commenced c 100 mybp"

If accepted, this change would leave Ischigualasto/Talampaya NP as the "oldest" S American natural WHS - Triassic (250 to 201mybp) - a "solid" assignment I would think since its OUV is as the "most complete continental fossil record known from the Triassic Period"

Author elsslots
Admin
#88 | Posted: 10 Aug 2021 08:34 
Solivagant:
defining feature of Canaima lies in its Tepuis and the "island evolution"

Sounds better indeed. I have updated the timeline.

Author Solivagant
Partaker
#89 | Posted: 13 Aug 2021 04:20 | Edited by: Solivagant 
Cerrado Protected Areas - CPA
The 2 inscribed criteria are
"The current protected areas of the site played a key role for thousands of years in maintaining the biodiversity of the Cerrado ecoregion" and "The site contains samples of all the key habitats that characterize the Cerrado ecoregion - one of the oldest tropical ecosystems of the Earth. It hosts more than 60% of all plant species and almost 80% of all vertebrate species observed in the Cerrado. All the endangered great mammals of the Cerrado are present, with the exception of the giant otter"

So, the "defining feature" of the Cerrado is its Ecosystem and we need to identify the time period which "created" what was inscribed

The Nomination file says nothing of use on the matter but Wiki states – "Cerrado vegetation is believed to be ancient, stretching back perhaps as far in a prototypic form as the Cretaceous, before Africa and South America separated. A dynamic expansion and contraction between cerrado and Amazonian rainforest has probably occurred historically, with expansion of the Cerrado during glacial periods like the Pleistocene. These processes and the resulting fragmentation in multiple refugia have probably contributed to the high species richness both of the Cerrado and of the Amazonian rainforest".

Across this long period of expansion and contraction, it appears that the "Cerrado" underwent other changes also. In particular, the disappearance of the area's "megafauna" as existed during much of the Pleistocene. But why did this happen? This paper sets out the views and issues -
a "Whether cerrados are anthropogenic or natural formations has been a matter of strong debate over the last century.... two types of hypotheses about the origin of the cerrado. The first favors the human-induced origin of the vegetation and is based on observations of fire-adapted species, which suggest that cerrados would result from the development of dry forests under the influence of fire. The second hypothesis supports the natural origin of the cerrados based on the occurrence of cerrados in areas only recently colonized by humans, and on the discovery of extinct giant mammals living in open forest landscapes at the end of the Pleistocene"
b "The floristic composition of the cerrado vegetation varied through time as it does today... The earliest record of cerrado-type vegetation dates back to 32,000 YBP... Vegetation resembling present-day cerrados does not occur prior to 7,000 YBP in central Brazil and 10,000 YBP in northern Brazil. Their presence in both regions is most likely a consequence of a progressive increase of seasonality, concomitant with an increase in temperature. Both factors, in addition to man's influence, contributed to increased fire frequencies, although cerrado vegetation was probably fire-adapted before people arrived in South America."

The general conclusions are that "that both hunting and climatic changes played important roles in the extinction of the South American megafauna......Widespread hunting by the Paleo- Indians would have caused an accentuated decline in the megaherbivore population. The changes in the climate, however, would have fragmented and restricted the distribution of those megaherbivores to places of low nutritional value, leaving them more vulnerable to local extinction as much to human, as to stochastic factors"

This article puts numbers on to the faunal losses and considers the impact these losses have had on the Cerrado vegetation. I noticed this quote "If we could go back in time at least ten thousand years, to the end of the Pleistocene, the savannas of South America (such as the Cerrado and the Pantanal) were more spectacular than the savannas of Africa. Whereas in Africa there exist only five mammals of more than a ton (elephant, two species of rhinoceroses, hippopotamus and the male giraffe), in South America during the Pleistocene there were more than 38 genera above 100 kilos (220 lbs.), and from ten to twelve species above a ton, in one single place". It then considers the impact of these losses on the vegetation – the plants which don't get their seeds spread etc etc. I hadn't previously been aware of the size of this change - imagine the savannas of Africa without their megafauna – they could still be wild natural places but very different from what they are today.

So, whilst the Cerrado biome first emerged in the Cretaceous and reached a peak in the Pleistocene I would conclude from the above that what we see today (and what got inscribed) is primarily a Holocene landscape arising from both manmade and climatic changes which started even before the Holocene. It is still worth preserving of course, where possible, against even greater change during the "Anthropocene"!

I suggest something along the lines of the following "rationale" statement which brings in the wider aspects
"Much Cerrado vegetation developed in prototype during the Cretaceous. Subsequently the area it covered extended and retracted particularly in exchange with Amazonian biota without significant underlying geological change. A peak of biodiversity was reached by the Pleistocene. Climatic changes and human activity (particularly hunting and fire) altered this considerably particularly via the loss of much of the megafauna. As a result today's preserved areas are significantly Holocene."

Author elsslots
Admin
#90 | Posted: 13 Aug 2021 12:17 
You're doing all this research Solivagant (thanks for that!), but in the end the answer for a criterion ix or x site always seems to be Holocene!

Page  Page 6 of 7:  « Previous  1  2  3  4  5  6  7  Next » 
Connections www.worldheritagesite.org Forum / Connections /
 Timelines

Your Reply Click this icon to move up to the quoted message


 ?
Only registered users are allowed to post here. Please, enter your username/password details upon posting a message, or register first.

 
 
 
www.worldheritagesite.org Forum Powered by Chat Forum Software miniBB ®
 ⇑