Mammoth steppe: a high-productivity phenomenon

Zimov, S. A.; Zimov, N.; Tikhonov, Alexei; Chapin, F. Stuart

doi:10.1016/j.quascirev.2012.10.005

Cited by 179 publications

(202 citation statements)

References 26 publications

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“…Matheus (2003) arrived at values similar to Bliss and Richards (1982). Zimov et al (2012) arrived at population estimates similar to our's for the interval 40e10 cal ka BP along the lower Lena River in northeastern Siberia (Table 1). Working with bones eroding out of the valley-fill deposit exposed at Duvanniy Yar (Strauss et al, 2012), Zimov calculated the number of animal carcasses per volume of sediment, divided by the total age of the deposit.…”

Section: How Many Megafauna Were There?supporting

confidence: 81%

“…Keeping in mind that this biome had a continental extent and that climate changed in a complex fashion over the tens of thousands of years during which it existed, the estimates in Table 1 agree that the Mammoth Steppe supported a significantly larger biomass of megafauna than live in the same regions today. Our data and those of Zimov et al (2012), which are the only "hard" data relevant to this question, both indicate megafaunal animals were 6e12Â more abundant than today, at least in certain parts of the Arctic and at certain times during the ice age. They also suggest that total megafaunal biomass may have been 30Â greater.…”

Section: How Many Megafauna Were There?supporting

confidence: 49%

“…Muskox bones are absent at Duvanniy Yar, and caribou bones are more abundant there than on the North Slope, but the relative abundances of the other taxa are similar. Zimov et al (2012) assert that other Quaternary bone beds in northern Siberia evidence megafauna population densities similar to those at Duvanniy Yar.…”

Section: How Many Megafauna Were There?mentioning

confidence: 91%

“…They also suggest that total megafaunal biomass may have been 30Â greater. At these high animal densities, feedbacks between the herbivorous megafauna and the rangeland ecology (McNaughton, 1984) would be inevitable (Zimov et al, 1995(Zimov et al, , 2012.…”

Section: How Many Megafauna Were There?mentioning

confidence: 99%

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Ice-age megafauna in Arctic Alaska: extinction, invasion, survival

Mann

Groves

Kunz

et al. 2013

Quaternary Science Reviews

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Groves, Pamela; Kunz, Michael L.; Reanier, Richard E.; and Gaglioti, Benjamin V., "Ice-age megafauna in Arctic Alaska: extinction, invasion, survival" (2013 a b s t r a c tRadical restructuring of the terrestrial, large mammal fauna living in arctic Alaska occurred between 14,000 and 10,000 years ago at the end of the last ice age. Steppe bison, horse, and woolly mammoth became extinct, moose and humans invaded, while muskox and caribou persisted. The ice age megafauna was more diverse in species and possibly contained 6Â more individual animals than live in the region today. Megafaunal biomass during the last ice age may have been 30Â greater than present. Horse was the dominant species in terms of number of individuals. Lions, short-faced bears, wolves, and possibly grizzly bears comprised the predator/scavenger guild. The youngest mammoth so far discovered lived ca 13,800 years ago, while horses and bison persisted on the North Slope until at least 12,500 years ago during the Younger Dryas cold interval. The first people arrived on the North Slope ca 13,500 years ago. Bone-isotope measurements and foot-loading characteristics suggest megafaunal niches were segregated along a moisture gradient, with the surviving species (muskox and caribou) utilizing the warmer and moister portions of the vegetation mosaic. As the ice age ended, the moisture gradient shifted and eliminated habitats utilized by the dryland, grazing species (bison, horse, mammoth). The proximate cause for this change was regional paludification, the spread of organic soil horizons and peat. End-Pleistocene extinctions in arctic Alaska represent local, not global extinctions since the megafaunal species lost there persisted to later times elsewhere. Hunting seems unlikely as the cause of these extinctions, but it cannot be ruled out as the final blow to megafaunal populations that were already functionally extinct by the time humans arrived in the region.

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Section: How Many Megafauna Were There?supporting

confidence: 81%

Section: How Many Megafauna Were There?supporting

confidence: 49%

Section: How Many Megafauna Were There?mentioning

confidence: 91%

Section: How Many Megafauna Were There?mentioning

confidence: 99%

See 2 more Smart Citations

Ice-age megafauna in Arctic Alaska: extinction, invasion, survival

Mann

Groves

Kunz

et al. 2013

Quaternary Science Reviews

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“…No changes were made to the vegetation model or to controls on soil input, which are only dependent on temperature and NPP; the mammoth-steppe biome is not explicitly modelled (Zimov et al, 2012).…”

Section: Simplifications and Limitationsmentioning

confidence: 99%

A simplified permafrost-carbon model for long-term climate studies with the CLIMBER-2 coupled earth system model

et al. 2014

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Abstract. We present the development and validation of a simplified permafrost-carbon mechanism for use with the land surface scheme operating in the CLIMBER-2 earth system model. The simplified model estimates the permafrost fraction of each grid cell according to the balance between modelled cold (below 0 • C) and warm (above 0 • C) days in a year. Areas diagnosed as permafrost are assigned a reduction in soil decomposition rate, thus creating a slow accumulating soil carbon pool. In warming climates, permafrost extent reduces and soil decomposition rates increase, resulting in soil carbon release to the atmosphere. Four accumulation/decomposition rate settings are retained for experiments within the CLIMBER-2(P) model, which are tuned to agree with estimates of total land carbon stocks today and at the last glacial maximum. The distribution of this permafrost-carbon pool is in broad agreement with measurement data for soil carbon content. The level of complexity of the permafrostcarbon model is comparable to other components in the CLIMBER-2 earth system model.

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Simulating soil organic carbon in yedoma deposits during the Last Glacial Maximum in a land surface model

Zhu

Peng

Ciais

et al. 2016

Geophysical Research Letters

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Substantial quantities of organic carbon (OC) are stored in the thick, ice‐rich, and organic‐rich sediments called yedoma deposits, distributed in eastern Siberia and Alaska today. Quantifying yedoma carbon stocks during the glacial period is important for understanding how much carbon could have been decomposed during the last deglaciation. Yet processes that yield the formation of thick frozen OC in yedoma deposits are missing in global carbon cycle models. Here we incorporate sedimentation parameterizations into the Organizing Carbon and Hydrology In Dynamic Ecosystems (ORCHIDEE‐MICT) land surface model, which leads to reasonable results in OC vertical distribution and regional budgets, compared with site‐specific observations and inventories for today's nondegraded yedoma region. Simulated total soil OC stock for the northern permafrost region during the Last Glacial Maximum (LGM) is 1536–1592 Pg C, of which 390–446 Pg C is within today's yedoma region. This result is an underestimation since we did not account for the potentially much larger yedoma area during the LGM than the present day.

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Mammoth steppe: a high-productivity phenomenon

Cited by 179 publications

References 26 publications

Ice-age megafauna in Arctic Alaska: extinction, invasion, survival

Ice-age megafauna in Arctic Alaska: extinction, invasion, survival

A simplified permafrost-carbon model for long-term climate studies with the CLIMBER-2 coupled earth system model

Simulating soil organic carbon in yedoma deposits during the Last Glacial Maximum in a land surface model

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