Chapter 4: The Steppe Bison

Together with the woolly mammoth, large herds of steppe bison (Bison priscus) have grazed. How far north has the steppe bison lived in Siberia and North America? How far north is the bison living now? To what kind of a climate and plant cover is it adapted?

Map: Where the steppe bison (Bison priscus) has lived in Eurasia during the time of the woolly mammoth: up to the shores of the Arctic Sea, up to the top of Taimyr Peninsula, at Cape Chelyuskin, near 77.4° North. According to R.-D. Kahlke (1994) Fig. 20. - The steppe bison (Bison priscus), together with a woolly mammoth (Mammuthus primigenius) in late Pleistocene Alaska. From B. Kurtén (1988). The steppe bison was adapted to the hard, dry ground-surface of the zonal steppe and forest-steppe, as growing now in southern Siberia, near 50° North, not to the soggy arctic tundra of today.

 

The steppe bison has grazed in North America and Eurasia up to the shores of the Arctic Sea, together with the woolly mammoth (R.-D. Kahlke, 1994, Plate 20). Its remains they have found at least up to 77.4°N, at Cape Chelyuskin, the northern tip of Taimyr Peninsula. - In what kind of a climate is the bison living now at the northern limit of its range?

The bison has lived in historical times (or is still living) in North America and Eurasia at the northern limit of its range in this climate: 140 (120-160) days above 5°C. 90 (70-150) days above 10°C. 34.5 (27-47) kcal cm² mean ann. net radiation at earth’s surface. 1700° (1400-2000°) 10°C.ts. 17.0° (16-19) mean July temperature. 300 (250-350) mm annual potential evapotranspiration (P.E.). There is either no permafrost at all, or only sporadic permafrost at its southern limit.

In Eurasia, the northern limit of the bison’s range is lying now about 1700 (1500-2000) km further south. And in North America, it has moved some 1300 km further southeast. The steppe bison was adapted to the hard, dry ground-surface of the zonal steppe and forest-steppe, as it is growing now in southern Siberia near 50°N. Its small hooves are not adapted to the soggy tundra of today. The hooves of the steppe bison are just as small as those of the living bison.

This means: The steppe bison has lived in north Siberia (together with the woolly mammoth), in a climate, as we find it now near 50°N, some 1700 km further south. The large bison bull, weighing 1,250 kg, is only able to live, where 189 g aboveground dry matter is growing per square meter per year (189 g DM/m² yr) (Belovsky, G. R., 1986). The steppe bison would not be able to live in the periglacial steppe-tundra (loess steppe, mammoth steppe) during the peak of the Last Glaciation. There was too little fodder. The 1,250-kg bison would not even be able to live now in the azonal dry steppe of the Yukon and Yakutia. The azonal dry steppe of NE Yakutia and the Southern Yukon are supposed to be the closest analog to the periglacial steppe-tundra, loess-steppe or mammoth steppe.

The azonal dry steppe near Tyubelyakh, NE Yakutia is growing now 20-40 g DM/m² yr at 190 mm ppt. yr. The azonal dry steppe of the Sartan River Valley of NE Yakutia, produces now 38-61 g DM/m² yr, at an annual precipitation of 153.8 mm. The south-facing azonal dry steppe on Sheep Mountain, Kluane Lake, Southern Yukon Territory, with its subarctic climate, produces now about 61.7 g DM/m² yr. It is growing from 200 mm annual precipitation.

 

The home range of the steppe bison during the time of the woolly mammoth in Eurasia and North America. From: R. D. Guthrie (1990:51) Fig. 2.6. The stippled line is the northern and southern limit of the area, where the steppe bison has lived then, according to Professor R. D. Guthrie. Actually, the steppe bison has grazed still further north: up to the shore of the present Arctic Sea, and still further north, on the now submerged continental shelf.