Chapter 2: Kolyma Lowland: Equivalent Latitude

In northeastern Yakutia, also in the Kolyma lowland, well-drained, south-facing slopes are often covered with azonal dry steppe. – When would this azonal steppe on the south-facing slopes become zonal steppe in the Kolyma lowland, growing also on the flat ground?

The American insect scientist (etymologist) Scott A. Elias reports: "Alfimov and Berman studied the biota, microclimate and soil conditions on both north- and south-facing slopes in the Kolyma lowland. The north-facing slopes are consistently colder and the active layer (the layer that thaws seasonally) is considerably thinner than on the south-facing slopes, where steppe vegetation persists in patches. The soils at the steppe site thaw deeply in summer, and are well enough drained to create xeric (= dry) habitats. The soils on the north-facing slope remain moist and support mesic- to moist temperatures at 20 cm depth on the south-facing slope average 25-26°C and soil surface temperatures reach 58-62°C.

"On the north-facing slope, soil temperatures at 20 cm depth reach only 1-2°C, and the water content of the soil approaches saturation. By mid-September the soils on the north-facing slope are frozen, whereas the soils on the south-facing slope remain thawed as late as mid-October. The steppe microclimate is very hot and dry in comparison with surrounding tundra environments, and the relict steppe communities survive in the north because of the stability of the microclimate established on south-facing slopes." - Elias, S. A. (1994:167).

The Kolyma lowland, in NE Siberia, lies at 150-160°E, 67-72°N, north of the Arctic Circle. In the Kolyma lowland, in June, early July, the soil temperature at a depth of 20 cm on the south-facing slope averages 25-26°C. On the north-facing slope, soil temperature at 20 cm depth averages only 1-2°C. And the water content in the soil reaches saturation. How warm would it have to be then in the Kolyma lowland during the warmest month of the year, so that the patches of azonal steppe, growing now on the south-facing slopes of Kolyma lowland, would also grow then as zonal steppe on the flat ground, like the steppe in Central Siberia?

25-26°C = av. 25.5°C. 1-2°C = av. 1.5°C. 25.5 + 1.5 = 27 : 2 = 13.5°C. Thus, the soil on the flat ground of Kolyma lowland, 20 cm below the surface, should have then during the warmest month of the year an average 13.5°C. 25.5 : 13.5 = 1.889.

This means: The south-facing slope in Kolyma lowland is 1.889 times warmer, than the flat ground during the warmest month of the year. The mean July air temperature in Kolyma lowland near 70°N is now about 12°C. 12°C x 1.889 = 22.67°C.

Result

The patches of azonal steppe, growing now on well-drained south-facing slopes of Kolyma lowland, near 70°N, will only be able to grow up there as zonal steppe on flat ground, if the warmest month of the year were 1.889 times warmer than now! It had to be then 22.67°C. – Where do we find now such a climate?

A mean July air temperature of 22.67°C we do find now in the lowland of West Siberia at 50°N. That is some 2160 km further south in latitude. The zonal mammoth steppe in northeastern Siberia can only have grown in a mild temperate climate, as we find it now in West Siberia at 50°N. The mean July temperature had to be then 22.7°C. There was then no arctic winter, no permafrost above the Arctic Circle, when the woolly mammoth was grazing there. But this does not tell us yet, how much it would have to rain per year in NE Siberia, so that enough grass and browse could have grown there, to feed the herds of woolly mammoths, steppe bison and wild horses.

Actual and potential evapotranspiration values for the different

physico-geographical zones of the former USSR (units: mm per year)

Russian Plain in Last Glaciation

What was the annual precipitation on the Russian Plain at the Last Glacial Maximum (LGM)? How much aboveground dry matter could have grown there? Could the steppe bison and the woolly mammoth have lived there? Would they have found there enough to eat?

Olga Soffer, University of Illinois (USA) has worked more than 12 years in Russia. She reports about her findings: "Between 20,000 and 18,000 years ago the northern half, extending approximately to the 53° parallel was covered by the Fennoscandian ice sheet. The ice did not form a uniform front but extended considerably further south in the Dnepr-Desner-Propyat’ basins area than it did in the east all along the Don. Thus sites on the central part of the plain were located much closer to the ice sheet, in some cases as close as 250 km (e.g. Pogon and Pushkari I), than were sites along the Don, which were about 800 km away (Kostenki 19).

"Secondly, sites in the center of the plain, as well as Kostenki 19, were located in the permafrost zone, while those in the steppe regions lay to the south. Finally, the estimated 87-90 m drop in sea-level at the time eliminated the sea of Azov and reduced the Black Sea to some 320,000 km² - thus making Crimea a part of the plain rather than the peninsula it is today.

"A sharp decrease in moisture was an equally important feature of the LGM. For the study area, especially its northern half, this meant precipitation of between 60 and 120 mm per year as opposed to present-values of about 600 mm. While today only about one-third of this falls as snow, light winter snowfall accounted for most of the available moisture during the LGM." - Soffer, O. (1990:232, 233).

During the Last Glacial Maximum (LGM), between 20,000 and 18,000 BP, the Russian Plain, especially its northern half, had a mean annual precipitation of 60 to 120 mm. Today it is about 600 mm. During the Last Glacial Maximum the Russian Plain had a mean annual precipitation of 60-120 mm = 90 mm. That is 6.6 times less than now. How much aboveground dry matter could have grown then in this periglacial climate on the Russian Plain? How much would have grown then in an arctic or subarctic climate, as we find it now in northeastern Yakutia and in the southern Yukon Territory, NW Canada?

The azonal dry steppe on the south-facing slopes of the southern Yukon, near large glaciers (Dall sheep range), is supposed to be just like the dry tundra-steppe of the Last Glaciation (V. Geist, 1971). It produces now 0.3085 g DM/mm ppt.yr. The 90 mm ppt/yr on the Russian Plain would have produced then during the Last Glacial Maximum, between 20,000 and 18,000 BP, only 28 g DM/m² yr.

The Yakutian azonal steppe, growing now in a subarctic climate, produces an average 0.23987 g DM/mm ppt.yr. The 90 (60-120) mm annual precipitation on the Russian Plain, during the Last Glacial Maximum, 20,000-18,000 years ago, would have produced then only 22 g DM/m² yr. Only the non-lactating reindeer would be able to live there. It needs 25 g DM/m².yr green vegetation for maintenance. The lactating reindeer needs 35 g DM/m².yr (Bliss, L. C. et al., 1981:440, 441). Neither the steppe bison, nor the woolly mammoth could have lived on such a dry periglacial steppe, growing only 22-28 g DM/m² per year. The large 1250-kg bison bull is only able to live, where 189 g DM/m² is growing per year (Belovsky, G. R. 1986). The elephant is only able to live, where 250 g DM/m² has grown per year (month by month). The elephant will starve to death, where only 200 g DM/m² has grown per year (Phillipson, J. 1975:171, 176). The woolly mammoth would also have thirsted to death in winter on the periglacial Russian Plain, when rivers, ponds and lakes were deeply frozen.

Europe’s Periglacial Steppe-Tundra

In what kind of a climate and on what kind of a plant-cover has the woolly mammoth lived during the last part of the late Pleistocene in Europe? Would this elephant have found enough to eat on the periglacial steppe-tundra or loess steppe during the coldest part of the Last Glaciation, while the ground was frozen several hundred meters deep? What have scientists found out about this now?

Dr. Anne Kathrin Gliemeroth, Institute of Botany, University of Hohenheim, near Stuttgart, SW Germany, has published now her findings. It is based on several years of fieldwork throughout Europe, also in Russia, up to the Ural Mountains. She has also studied in 1992 the zonal steppes in Tibet. The title of her new book is: Paläoökologische Untersuchungen über die letzten 22,000 Jahre in Europa (Paleoecological Investigations about the last 22,000 years in Europe) (1995). Professor Burkhard Frenzel, Institute of Botany, University of Hohenheim, has published it. The total aboveground biomass (living and dead) from 22,000 to 11,800 B.P.) for the different areas in Europe is based on her Table 1: Reconstructed vegetation units, and Fig. 2: Biomass-reconstruction in Europe, aboveground biomass (1995:14, 16).

Glacial Maximum (22,000 B.P.)

Her map (Fig. 4, p.22, 23) shows the reconstructed vegetation and biomass in Europe for the glacial maximum (22,000 B.P.). The different figures on her map do show us, what kind of a plant-cover was growing then in Europe, and how much total aboveground biomass (living and dead) has grown there. Figure 7 on map of Glacial Maximum (22,000 years ago) in Europe: from southern England eastwards to the Russian Plain (west of the Ural Mountains), and from south of the Black Sea and Caspian Sea to northern Russia, does show us that up to about 65°N steppe-tundra was growing with intensive loess production.

Dr. Anne Kathrin Gliemeroth (1995:20) reports about her findings about the Glacial Maximum(22,000 B.P.) in Europe: "In the central and eastern part of Europe, a steppe-tundra (7) was growing; ... an intensively drifting loess in these places, disturbed by the action of frost, has strongly hindered the growth of plants. Still poorer has been the vegetation on the mountains of central Europe, and on the foothills of the Alps...

"Reconstructing the aboveground biomass during the Glacial Maximum: Only by comparing (the steppe-tundra) with the High-Asiatic cold-steppe, it has been possible, to find recent biomass-values for the calculation. Also today’s areas close to glaciers, where some loess is still being deposited, may be viewed as analogs.

"During the Glacial Maximum, the fossil soil is missing nearly completely. The presence of permafrost in the ground, and the intensive deposition of loess in large parts of Europe, do indicate, instead, a very inhospitable climate. ... It was found that large herbivores and human beings, north of the line Pyrenees, Alps, Carpathians, and the central Ukraine ... were nearly completely absent. This verifies indirectly the extremely low values of the aboveground biomass. ... One has not been able to find during the time of the Glacial Maximum in Europe any increase in humus." - Gliemeroth, A. K. (1995:21).

How much total aboveground biomass did the steppe-tundra of Central and Eastern Europe have during the coldest part of the Last Glaciation, some 22,000 years ago, according to ¹⁴C-dating? - Central and Eastern Europe’s steppe-tundra, with its intensively drifting loess (growing on continues permafrost), contained a total aboveground biomass (living and dead) of about 121 gDM/m². How much fresh, green vegetation has grown during the coldest part of the Last Glaciation on Central and East Europe’s steppe-tundra, eastwards to the Ural Mountains? Would the mammoth and rhinoceros have found there enough to eat? How much green biomass does the total aboveground biomass of the Eurasian dry steppe now contain?

The Professors of Botany H. Walter and S. W. Breckle (1986:191) report: The total above-ground biomass of the dry steppe (shortgrass plain) in Eastern Europe contains 9% green matter (dry weight). – The moderately dry steppe of West Siberia and the Altai area (Central Asian High Plateau) contains 18% green matter (dry wt). – The total aboveground biomass of the dry steppe and of the steppe-half-desert in West Siberia and the Altai area (Central Asian High Plateau) contains 14% green matter (dry wt).

Glacial Maximum in Europe (22,000 B.P.): vegetation and biomass. After: A. K. Gliemeroth (1995:22). - Area 7 on map: Steppe-tundra with intensive loess production. Total aboveground biomass of periglacial steppe-tundra around 121 g/m² (dry weight). Annual aboveground growth of vegetation around 17 g/m². - Area 3: Snow-ground and solifluction-associations. Also 121 g/m² total aboveground biomass (living and dead). 17 g/m² aboveground growth per year (dry weight). Neither the mammoth, nor the rhinoceros, nor the bison could have lived during the Glacial Maximum (the height of the Last Ice Age), 22 000 years ago, on Europe’s periglacial steppe-tundra. They would have starved to death.

Result

From this I do conclude: The total aboveground biomass of the dry steppe contains an average 14% green matter (dry weight). That is, the fresh, green vegetation growing there each year. – How much aboveground vegetation (dry matter) must have grown then on the steppe-tundra of Central and Eastern Europe during the coldest part of the Last Glaciation (22,000 B.P.)?

The total aboveground biomass of steppe-tundra during the Glacial Maximum (22,000 B.P.) was about 121 gDM/m².yr (living and dead). 14% of this was fresh, green vegetation, growing there in summer. The steppe-tundra has grown then about 17 gram aboveground green dry matter per square meter per year (17 gDM/m².yr).

And what do we find further north? - In Northern Russia, from 65°N up to the Arctic Coast, according to A. K. Gliemeroth’s map, Fig. 7, snow-ground and solifluction associations were growing up there during the Glacial Maximum (22,000 B.P.). This arctic plant-cover has also a total aboveground biomass of about 121 gDM/m² yr. Also in northern Russia, 17 gDM/m² yr were growing (at 14% of the total aboveground biomass). At 17 gDM/m² yr aboveground vegetation (dry weight), growing on the steppe-tundra of Central and Eastern Europe during the coldest part of the Last Glaciation (22,000 B.P.), not even the reindeer and the muskox could have lived there. They would have starved to death. Nor would the bison, woolly rhinoceros, and mammoth have found there enough to eat. They would have starved to death within a few weeks or months.