Paleoindians in Beringia: Evidence from Arctic Alaska

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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“…The earliest archaeological date from the North Slope has a 2s range of 13.7e13.3 cal ka BP (Kunz and Reanier, 1994;Mann et al, 2001) (Fig. 8).…”

Section: A Role For Humans?mentioning

confidence: 99%

“…The oldest date on archaeological charcoal comes from the Mesa Site (Kunz and Reanier, 1994;Mann et al, 2001) in the Arctic Foothills and dates to 13.5 cal ka BP (Fig. 8).…”

Section: Temporal Patterns Of Species Abundancementioning

confidence: 99%

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

Mann

Groves

Kunz

et al. 2013

Quaternary Science Reviews

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“…Much of the Arctic Foothills region has never been glaciated. Areas near the Brooks Range, including the Mesa archaeological site (Kunz and Reanier, 1994), were last glaciated during the Tertiary and early Pleistocene. During the Last Glacial Maximum (LGM), glaciers in the Brooks Range terminated along the northern range front (Hamilton, 1986).…”

Section: Study Areamentioning

confidence: 99%

“…To describe the paludification history of a topographically and pedologically representative portion of the Arctic Foothills, 19 TBO and LCO dates were obtained from a 10-km 2 area around the Mesa archaeological site (Kunz and Reanier, 1994). Auger sites were positioned along toposequences extending from rocky, frost-disturbed interfluves to alluvial toeslopes.…”

Section: Paludification Of the Arctic Foothills And Arctic Coastal Plainmentioning

confidence: 99%

Responses of an arctic landscape to Lateglacial and early Holocene climatic changes: the importance of moisture

Mann

Peteet

Reanier³

et al. 2002

Quaternary Science Reviews

116

132

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Many of the physical and biological processes that characterize arctic ecosystems are unique to high latitudes, and their sensitivities to climate change are poorly understood. Stratigraphic records of land-surface processes and vegetation change in the Arctic Foothills of northern Alaska reveal how tundra landscapes responded to climatic changes between 13,000 and 8000 14 C yr BP. Peat deposition began and shrub vegetation became widespread ca. 12,500 14 C yr BP, probably in response to the advent of warmer and wetter climate. Increased slope erosion caused rapid alluviation in valleys, and Populus trees spread northward along braided floodplains before 11,000 14 C yr BP. Lake levels fell and streams incised their floodplains during the Younger Dryas (YD) (11,000-10,000 14 C yr BP). A hiatus in records of Populus suggest that its geographic range contracted, and pollen records of other species suggest a cooler and drier climate during this interval. Basal peats dating to the YD are rare, suggesting that rates of paludification slowed. Immediately after 10,000 14 C yr BP, lake levels rose, streams aggraded rapidly again, intense solifluction occurred, and Populus re-invaded the area. Moist acidic tundra vegetation was widespread by 8500 14 C yr BP along with wet, organic-rich soils. Most of these landscape-scale effects of climatic change involved changes in moisture. Although low temperature is the most conspicuous feature of arctic climate, shifts in effective moisture may be the proximate cause for many of the impacts that climate change has in arctic regions. r

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“…First, its ice-age megafauna included iconic species like woolly mammoth (Mammuthus primigenius), steppe bison (Bison priscus), and cave lion (Panthera spelaea) (14). Second, the local extinctions of megafauna on Alaska's North Slope occurred at a time when archaeological remains are rare, suggesting that people seldom ventured there (15,16). Third, bone preservation in arctic environments tends to be excellent because of the presence of permafrost (perennially frozen ground), which makes it possible to 14 C date large numbers of bones from many different species (SI Appendix, Table S1).…”

mentioning

confidence: 99%

Life and extinction of megafauna in the ice-age Arctic

Mann

Groves

Reanier³

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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Understanding the population dynamics of megafauna that inhabited the mammoth steppe provides insights into the causes of extinctions during both the terminal Pleistocene and today. Our study area is Alaska's North Slope, a place where humans were rare when these extinctions occurred. After developing a statistical approach to remove the age artifacts caused by radiocarbon calibration from a large series of dated megafaunal bones, we compare the temporal patterns of bone abundance with climate records. Megafaunal abundance tracked ice age climate, peaking during transitions from cold to warm periods. These results suggest that a defining characteristic of the mammoth steppe was its temporal instability and imply that regional extinctions followed by population reestablishment from distant refugia were characteristic features of ice-age biogeography at high latitudes. It follows that long-distance dispersal was crucial for the long-term persistence of megafaunal species living in the Arctic. Such dispersal was only possible when their rapidly shifting range lands were geographically interconnected. The end of the last ice age was fatally unique because the geographic ranges of arctic megafauna became permanently fragmented after stable, interglacial climate engendered the spread of peatlands at the same time that rising sea level severed former dispersal routes. (10,000-45,000 calendar y ago) when some 65% of terrestrial megafauna genera (animals weighing >45 kg) became globally extinct (1). Based on what we know about recent species extinctions, the causes of extinction are usually synergistic, often species-specific, and therefore, complex, which implies that there is no universal explanation for end-Pleistocene extinctions (2, 3). Globally and specifically in the Arctic (3-10), megafaunal extinctions have been variously blamed on overhunting, rapid climate change, habitat loss, and introduced diseases (3-10). Further complicating a clear understanding of the causes of ice-age extinctions is that the magnitude and tempo of environmental change during the last 100,000 y of the Pleistocene were fundamentally different than during the Holocene (11), and these differences had far-reaching implications for community structure, evolution, and extinction causes (12).A recent survey comparing the extinction dates of circumboreal megafauna with ice-age climate suggests that extinctions and genetic turnover were most frequent during warm, interstadial events (13). However, the mechanisms for these extinctions remain unclear, partly because this previous study considered multiple taxa living in many different ecosystems. Here, we focus on five megafaunal species that coinhabited a region of the Arctic with an ecological setting that is relatively well-understood. To avoid the methodological problems involved in pinpointing extinction dates (13), we infer population dynamics from changes in the relative abundance of megafauna over time. Using a uniquely large dataset of dated megafaunal bones from one particular area, we t...

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Paleoindians in Beringia: Evidence from Arctic Alaska

Cited by 51 publications

References 17 publications

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

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

Responses of an arctic landscape to Lateglacial and early Holocene climatic changes: the importance of moisture

Life and extinction of megafauna in the ice-age Arctic

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