Sunday, December 1, 2013

Megafauna Extinctions in Japan

The nature of megafaunal extinctions during the MIS 3–2 transition in Japan

Christopher J. Norton, Youichi Kondo, Akira Ono, Yingqi Zhang, Mark C. Diab
Quaternary International 211 (2010) 113–122
(Link)
 
Abstract
The nature of late Quaternary megafaunal extinctions has been the subject of intense debate since the 960s. Traditionally, scientists cite either climatic changes or human predation as the primary reason for worldwide megafaunal extinctions. In many island cases (e.g., Madagascar, New Zealand), scientists have had a tendency to lean towards humans as being the direct or indirect dominant cause for the relatively quick extirpation of indigenous megafaunas. This study evaluates the record for megafaunal (e.g.,Palaeoloxodon, Mammuthus, Sinomegaceros) extinctions in the Japanese islands and draw the tentative conclusion that: (1) humans directly and/or indirectly influenced the extinction of some large herbivores;and (2) the megafaunal extinctions likely began earlier than originally proposed; during the marine isotope stage (‘‘MIS’’) 3–2 transition (w30–20 ka) rather than during the MIS 2–1 (w15–10 ka) shift that roughly coincides with the advent of the Jomon period in Japan. However, we temper our findings due to the current paucity of sites in Japan that have associated archaeology and vertebrate paleontological materials that date to the MIS 3–2 transition.

 

Timing of megafaunal extinction in the Late Pleistocene on the Japanese Archipelago

Akira Iwase, Jun Hashizume, Masami Izuho, Keiichi Takahashi, Hiroyuki Sato
Quaternary International 255 (2012)
(Link)

Abstract
In the late Late Pleistocene (lLP), Japanese terrestrial large mammals consisted of two main groups; the Palaeoloxodon-Sinomegaceroides complex and the mammoth fauna. The former inhabited temperate forests and the latter were adapted to patches of taiga and grassland in cold environments. Among the two groups, almost all large mammals became extinct in the Late Quaternary. The lLP extinction is one of the most interesting topics currently debated in Japan.
    This paper evaluates previously reported radiocarbon dates of mammal fossils to determine the timing of lLP megafaunal extinctions on the Japanese Archipelago. Unreliable specimens which were dated by conventional 14C decay counting, samples obtained from poorly preserved fossils, samples inconsistent with geological context, and samples dated by combining bone fragments of several species and whose exact provenances are unknown are rejected. The timing of extinctions was compared with the vegetational changes. As a result, the present paper indicates that the extinction of large mammals in the Palaeoloxodon-Sinomegaceroides complex roughly coincided with the onset of the last glacial maximum (LGM: from ca. 25,000 BP to 16,000 BP) and subsequent domination by subarctic conifers. In contrast, the mammoth fauna survived the LGM and became extinct or migrated northward when the climate started to ameliorate. The lLP extinction on the Japanese Islands occurred in two pulses. These results imply that the main causes of lLP extinction on the Japanese Archipelago were changes of the ecosystem driven by climatic changes rather than “overkill” by human hunters.

11 comments:

  1. Two conflicting papers on the role of humans in megafauna extinctions. Personally I think the second one is deliberately evading the role of humans. Quote:

    "The timing of extinctions was compared with the vegetational changes. As a result, the present paper indicates that the extinction of large mammals in the Palaeoloxodon-Sinomegaceroides complex roughly coincided with the onset of the last glacial maximum (LGM: from ca. 25,000 BP to 16,000 BP) and subsequent domination by subarctic conifers".

    Ignoring the real possibility that it was the megafauna extinction that contributed to the change in vegetation. And the date fits remarkably well with the comment in the ealier paper on Jomon mt-DNA:

    "The coalescence time of N9b (ca. 22,000 years) was before or during the last glacial maximum, implying that the initial trigger for the Jomon migration in Hokkaido was increased glaciations during this period".

    Of course that coalescence time may not indicate the haplogroup's arrival in Japan, but it may do. Especially with the comment regarding the trigger for migration. And change in climate may have been what enabled the expansion to Japan in the first place.

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  3. I put these papers up because they both clearly indicate that Japan was occupied from at least 30,000 years ago. The second paper give a very clear picture of which animals lived in Japan over the last 40,000 years.

    Interestingly enough, mammoth lived in Hokkaido, but further south, on Honshu, there were other large animals including a large deer (Sinomegaceros yabei). The second paper records a wolf fossil dated to 31,000BP.

    Wolves (and probably humans) certainly reached Honshu by 31,000BP.

    I bought both these papers. If you want the pdfs for them, my email is marniedunsmore@gmail.com

    They're both enthralling to read.

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  4. Before reading this I would have believed that human occupation of Japan commenced ca. 30,000 years ago and that megafauna extinction should have commenced around the same time and was puzzled by research tending to show a much later megafauna extinction. This paper tends to confirm my earlier biases.

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  5. From the Norton paper:

    1. The process of Palaeoloxodon, Sinomegaceros, and Mammuthus
    extinction in Japan was influenced by the initial human colonization
    of the Japanese archipelago after w50 ka, particularly
    as evident from the human-megafaunal interactions at sites
    like Tategahana. However, the initial human dispersals into the
    archipelago were likely small-scale, as indicated by the low
    density of archaeological sites and the low density of behavioral
    traces at each of the sites purportedly dated betweenw50
    and 30 ka.

    2. After w30 ka more than 5400 Paleolithic archaeological sites
    appear in Japan. This directly reflects the significant increase in
    human population densities and proportion of the islands
    utilized, which would have directly or indirectly influenced
    megafaunal home ranges.

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  6. From the Iwase paper:

    It is also certain that humans have inhabited the Japanese
    Archipelago since 40e35 ka, the onset of Early Upper Palaeolithic
    (Izuho, 2010; Izuho and Sato, 2008), considerably earlier than the
    occurrence of megafaunal extinction. This implies that the lLP
    megafauna coexisted with human hunters for at least 10,000 years.

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  7. "the initial human dispersals into the
    archipelago were likely small-scale, as indicated by the low
    density of archaeological sites and the low density of behavioral
    traces at each of the sites purportedly dated betweenw50
    and 30 ka."

    And perhaps largely confined to more southern regions. That would allow the north to act as a population reservoir until humans were able to move yet further north.

    "This implies that the lLP
    megafauna coexisted with human hunters for at least 10,000 years".

    Perhaps through the scenario I mentioned.

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  8. Terry,

    For early the Paleolithic prehistory of Japan, the papers specifically mention the site of Tategahana.

    Some of the papers for this site are open access, such as this one:

    Palaeoloxodon naumanni and its environment at the
    paleolithic site of Lake Nojiri, Nagano Prefecture,
    Central Japan

    Y. Kondo, N. Mazima, Nojiri-ko Research Group

    If you read carefully, you'll see that on Honshu, there were many species of animals, including Sinomegaceros yabei. You don't see Sinomegaceros yabei on Hokkaido, so I'm wondering if the reason for the early habitation of Honshu, and not Hokkaido, is that these hunters focused on the large deer (Sinomegaceros yabei), and also appreciated the more temperate and stable climate of Honshu, as opposed to Hokkaido.

    Correspondingly, the wolf fossil mentioned in the Iwase paper, dated to 31,000BP, is also on northern Honshu.

    The Japanese wolf appears to have been a "gracilized wolf", not the ectomorphic wolf mentioned in some recent papers on Siberian Wolves. Also, again, the recent Thalmann dog domestication paper indicates that the Japanese wolf was related to the wolfs that were at the cusp of dog domestication.

    These wolves were likely not hunters of mammoths. It's more likely that they were hunters of deer. If so, that would explain, as least for the wolves, why Honshu was more attractive for them than Hokkaido.

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  9. "I'm wondering if the reason for the early habitation of Honshu, and not Hokkaido, is that these hunters focused on the large deer (Sinomegaceros yabei), and also appreciated the more temperate and stable climate of Honshu, as opposed to Hokkaido".

    I'm fairly sure it's the latter. Although mountainous Nagano is about the same lattitude as Tokyo, 36 degrees. Hokkaido in Winter is stunningly cold. I visited the capital, Sapporo, in Winter. It is extremely likely that early Japanese made Summer trips to Hokkaido of course.

    Thanks for the papers you sent, by the way. I haven't got round to reading them yet.

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  11. That's very interesting!! Unfortunately, I've never been to Japan, so lucky you that you have.

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