American mastodon extirpation in the Arctic and Subarctic predates human colonization and terminal Pleistocene climate change

Abstract

Significance New radiocarbon ( 14 C) dates on American mastodon ( Mammut americanum ) fossils in Alaska and Yukon suggest this species suffered local extirpation before terminal Pleistocene climate changes or human colonization. Mastodons occupied high latitudes during the Last Interglacial (∼125,000–75,000 y ago) when forests were established. Ecological changes during the Wisconsinan glaciation (∼75,000 y ago) led to habitat loss and population collapse. Thereafter, mastodons were limited to areas south of the continental ice sheets, where they ultimately died out ∼10,000 14 C years B.P. Extirpation of mastodons and some other megafaunal species in high latitudes was thus independent of their later extinction south of the ice. Rigorous pretreatment was crucial to removing contamination from fossils that originally yielded erroneously “young” 14 C dates.

Osteological Assessment of PleistoceneCamelops hesternus(Camelidae: Camelinae: Camelini) from Alaska and Yukon

“…Alternatively, western camels may have dispersed northward into and occupied the eastern Beringia only during the relatively warm Last Interglaciation (Sangamonian), a hypothesis supported by emerging radiocarbon and stratigraphic data (Zazula et al, 2011;Heintzman et al, 2015). This interpretation correlates well with interpretation of the similar, but more extensive, radiocarbon dataset for arctic and subarctic American mastodons (Mammut americanum) (Zazula et al, 2014). Other taxa known to be very rare in high-latitude faunas, such as Jefferson's ground sloth (Megalonyx jeffersonii) and giant beavers (Castoroides ohioensis) (Harington, 1990), may have been similarly constrained ecologically to interglacial forests and shrublands (Muhs et al2001), although this would need to be tested with appropriately large radiocarbon and stratigraphic datasets.…”

Bigger kill than chill: The uneven roles of humans and climate on late Quaternary megafaunal extinctions

“…As Grayson points out, numerous recent locality-and regional-scale studies demonstrate the local disappearance of megafauna before the arrival of humans, and in concert with late-Pleistocene climatic changes (e.g., Zazula et al 2014, Rozas-Davila et al 2016; however, other sites do provide evidence for human-megafauna overlap and even interaction, and most continental-and global-scale studies show a strong temporal coincidence between human arrival and megafauna extinction that does not always coincide with climate changes (e.g., Araujo et al 2015, Surovell et al 2016. As Grayson points out, numerous recent locality-and regional-scale studies demonstrate the local disappearance of megafauna before the arrival of humans, and in concert with late-Pleistocene climatic changes (e.g., Zazula et al 2014, Rozas-Davila et al 2016; however, other sites do provide evidence for human-megafauna overlap and even interaction, and most continental-and global-scale studies show a strong temporal coincidence between human arrival and megafauna extinction that does not always coincide with climate changes (e.g., Araujo et al 2015, Surovell et al 2016.…”

Late Pleistocene (Rancholabrean) Mammalian Assemblage from Paw Paw Cove, Tilghman Island, Maryland

“…The American mastodon is among the most well-known Pleistocene mammals. Fossil remains have been recovered from Alaska to Mexico (Kurtén and Anderson, 1980:344;Polaco et al, 2001;Zazula et al, 2014). American mastodon fossils appear to be concentrated in the Great Lakes, along the Atlantic Coast (Dreimanis, 1968), in the Mississippi River valley, and in Florida (FAUNMAP Working Group, 1994:424-425).…”