Современные люди с недоверием относятся к идее охоты на мамонта. Мамонта защищает толстая шкура и слой жира. С другой стороны, что ему стоит передавить охотников?
есть разные мнения во первых не понятно почему последнее потепление оказалось настолько хуже нескольких предыдущих, когда значительных вымираний не отмечено а динамика температуры очень похожа
в прошлые кризисы популяции животных могли проходить через сильное сокращение численности но выживать и восстанавливаться во-вторых как-то подозрительно эти вымирания совпадают с прибытием людей, и почему-то это всегда мегафауна, а не мыши какие-нибудь. размерная избирательность этого вымирания не имеет аналогов в кайнозое (а может и не только в кайнозое)
If the Climatic Hypothesis explained vegetation and animal dynamics, steppe-like vegetation would have been replaced by tundra vegetation during the BWE, and the steppe would have been reestablished during the Younger Dryas, when the climate returned to glacial conditions. But in fact, Guthrie (2006) data indicates opposite. Glacial climate was not favorable for animals in Alaska and the Yukon. During the LGM nine animal species went extinct there (Guthrie, 2006). When the climate warmed from 15,000 to 12,400 radiocarbon years BP there was a substantial rise in abundance of grasses and sedges, and animal densities increased (Fig. 1). Pollen influx of Artemisia, a drought-adapted species, rose even more than the influx of other species (Fig. 1). ...
Approximately 12,400 years ago an abrupt change occurred: horses vanished, bison disappeared for over 300 years, and mammoth and elk populations began to decrease sharply (Fig. 1). It is clear that this abrupt faunal change was not triggered by vegetation change, because vegetation was stable during this period (Fig. 1). The only thing corresponding with these massive extinctions was the first evidence of humans (12,370 14C years before present) (Fig. 1). It therefore appears plausible that a relatively small number of hunters triggered the collapse of several herbivore populations (Martin, 1967).
After the first appearance of humans, some of the species recovered their populations (which is in agreement with modeling results, Alroy, 2001), but human population continued to increase and this led to herbivores’ extinction. It was only well after that that pastures degraded and dwarf betula appeared (Fig. 1). The appearance of moose (Alces) at 12,200 radiocarbon years BP closely corresponds with a decrease in Salix and rise in dwarf Betula, which is not the usual forage for the moose. One possible explanation for this shift is that, as long as there were abundant bison, elk, and mammoth, which actively ate willow sprouts, willow shrubs would not have grown above the snow cover. Moose (tallest hoofed animal) may have appeared in large numbers only when populations of other animals had decreased, creating a new feeding nicheetall willow shrubs
во первых не понятно почему последнее потепление оказалось настолько хуже нескольких предыдущих, когда значительных вымираний не отмечено а динамика температуры очень похожа
в прошлые кризисы популяции животных могли проходить через сильное сокращение численности но выживать и восстанавливаться
во-вторых как-то подозрительно эти вымирания совпадают с прибытием людей, и почему-то это всегда мегафауна, а не мыши какие-нибудь. размерная избирательность этого вымирания не имеет аналогов в кайнозое (а может и не только в кайнозое)
Body size downgrading of mammals over the late Quaternary
https://science.sciencemag.org/content/360/6386/310
https://www.researchgate.net/publication/305489176_Human_Dispersal_and_Late_Quaternary_Megafaunal_Extinctions_the_Role_of_the_Americas_in_the_Global_Puzzle
Reply
If the Climatic Hypothesis explained vegetation and animal dynamics, steppe-like vegetation would have been replaced by tundra vegetation during the BWE, and the steppe would have been reestablished during the Younger Dryas, when the climate returned to glacial conditions. But in fact, Guthrie (2006) data indicates opposite. Glacial climate was not favorable for animals in Alaska and the Yukon. During the LGM nine animal species went extinct there (Guthrie, 2006). When the climate warmed from 15,000 to 12,400 radiocarbon years BP there was a substantial rise in abundance of grasses and sedges, and animal densities increased (Fig. 1). Pollen influx of Artemisia, a drought-adapted species, rose even more than the influx of other species (Fig. 1). ...
Approximately 12,400 years ago an abrupt change occurred: horses vanished, bison disappeared for over 300 years, and mammoth and elk populations began to decrease sharply (Fig. 1). It is clear that this abrupt faunal change was not triggered by vegetation change, because vegetation was stable during this period (Fig. 1). The only thing corresponding with these massive extinctions was the first evidence of humans (12,370 14C years before present) (Fig. 1). It therefore appears plausible that a relatively small number of hunters triggered the collapse of several herbivore populations (Martin, 1967).
After the first appearance of humans, some of the species recovered their populations (which is in agreement with modeling results, Alroy, 2001), but human population continued to increase and this led to herbivores’ extinction. It was only well after that that pastures degraded and dwarf betula appeared (Fig. 1). The appearance of moose (Alces) at 12,200 radiocarbon years BP closely corresponds with a decrease in Salix and rise in dwarf Betula, which is not the usual forage for the moose. One possible explanation for this shift is that, as long as there were abundant bison, elk, and mammoth, which actively ate willow sprouts, willow shrubs would not have grown above the snow cover. Moose (tallest hoofed animal) may have appeared in large numbers only when populations of other animals had decreased, creating a new feeding nicheetall willow shrubs
https://vk.com/doc4228100_494894129?hash=a92b1e6d157e7f93aa&dl=2a80d625f80481678b
Reply
Leave a comment