The impact of mammoths on their biome: clash of two paradigms
Deinsea , Volume 9 - Issue 1 p. 365- 380
Mammoths, woolly rhinoceroses, musk oxen, primitive bisons, and horses of northern races were stenobiotic cryoxerophiles living only under extreme cryoarid conditions according to the ‘steppetundra crash paradigm’. These animals are considered to be strict grazers on arid steppe-tundra grasses; hence, the possibility that mammoths maintain their pastures the way modern elephants do is rejected. Climatists claim that mammoths and their faunal satellites were killed by the Holocene warming a result of their inability to feed themselves in any of modern landscapes and to withstand the weather-caused losses. Their survival throughout interglacials is considered as resulting from climatic instability: short warm episodes are said to have alternated with very cold ones. It is believed that a permanent Arctic Ocean ice-shield persisted along the Siberian coast even in summer; its cooling and aridifying influence maintained steppe-tundras and similar ecosystems throughout Northern Eurasia. On the contrary, the stable Holocene warming resulted in the disappearance of this ice-shield, in the destruction of the ecosystem of the mammoths, and in megafaunal extinctions. This conception is based mainly on the properties of Eemian Greenland ice layers. However, these layers do not indicate the real Eemian climate. Non-altered Antarctic ice cores and Atlantic deep sea cores show that the Eemian optimum climate was as stable as the Holocene one. The idea of the persistence of the Arctic ice-shield throughout interglacials also contradicts with this evidence. The real reason why woolly mammoth and rhino persisted throughout interglacials (as well as throughout glacials) is in their tolerance to a vast range of climates and their ability to maintain highly productive pasture ecosystems. Contrary to the opinion of climatists, these pachyderms were polyphages that ate various herbaceous and woody plants. They held back forest and tundra vegetation by various direct and indirect influences. Whatever the climate was, pachyderms prevented the appearance of closed forests and they ensured the predominance of grasses and herbs over mosses and shrublets, as well as high mosaicism of the vegetation. The pachyderms trampled on snow and broke the frozen snow crusts, thus facilitating the smaller ungulates to overwinter. Similarly, Paleoloxodon and Dicerorhinus created vast meadows throughout the temperate forest zone. Giant deer, bisons, horses, etcetera, used these meadows. The ecosystem impact of the climate-resistant pachyderms caused remarkable stability of pasture ecosystems throughout the Pleistocene. In addition, the largest carnivores were important prehistoric stabilising agents, due to their pressure on populations of humans, wolves and herbivores. The Pleistocene crisis in the Palearctic included the same main processes as in other continental realms: (1) liberation of mankind from carnivore control, (2) human-induced removal of pachyderms, (3) drastic environmental changes harmful to megafauna as a result of this removal, (4) secondary extinctions of herbivores as a result of environmental effects of pachyderms, (5) impoverishment of the large predator guild due to the great prey shortage aggravated by the other reasons, (6) other secondary extinctions, (7) installation of a new equilibrium. Due to the long coevolution of Palearctic megafauna with man, the extinction process in Palearctic was long-lasting and less catastrophic when compared to the Nearctic situation.