Flightless ducks, giant mice and pygmy mammoths: Late Quaternary extinctions on California's Channel Islands

Abstract

Explanations for the extinction of Late Quaternary megafauna are heavily debated, ranging from human overkill to climate change, disease and extraterrestrial impacts. Synthesis and analysis of Late Quaternary animal extinctions on California's Channel Islands suggest that, despite supporting Native American populations for some 13,000 years, few mammal, bird or other species are known to have gone extinct during the prehistoric human era, and most of these coexisted with humans for several millennia. Our analysis provides insight into the nature and variability of Quaternary extinctions on islands and a broader context for understanding ancient extinctions in North America.

Late Quaternary sea-level history and the antiquity of mammoths (Mammuthus exilisandMammuthus columbi), Channel Islands National Park, California, USA

“…In addition, it is important to recognize that with post-glacial sea level rise in the latest Pleistocene/earliest Holocene, many potentially important archeological sites on the northern Channel Islands would now be submerged on what are presently the insular shelves (Clark et al, 2014;Reeder-Myers et al, 2015). Nevertheless, Rick et al (2012b) concluded that climate change and ecological disturbance were likely the main causes for mammoth extinction on the Channel Islands. These investigators also point out that with post-glacial sea level rise, one consequence Fig.…”

“…With post-glacial warming, one could also add vegetation community change (Heusser, 1995(Heusser, , 2000 and alteration of freshwater sources as stressors on mammoth populations. An examination of the new evidence for mammoth antiquity on the Channel Islands, presented here, provides a partial test of the hypothesis presented by Rick et al (2012b) that mammoth extinction on the Channel Islands was due to climate change, ecological disturbance, and loss of land area. Given the findings reported here that mammoth remains are at least as old as~80 ka, it is possible to consider how glacial-interglacial climate and sea level change could have affected mammoths in the penultimate Quaternary climate cycle.…”

“…Despite the possible temporal overlap of humans and mammoths, there is currently no direct evidence that humans hunted mammoths on the Channel Islands (Rick et al, 2012b). Martin and Steadman (1999) suggest that a "commando raid" type of scenario is possible for Crete, Ireland, Wrangel Island (Siberia), and the Channel Islands, wherein stone-age hunters overrun an island, slaughter preferred prey (such as mammoths), quickly discover they cannot sustain an existence, and depart without leaving any archeological evidence of their visit.…”

Sea level, paleogeography, and archeology on California's Northern Channel islands

“…the coastal plain habitat (Figs. 2 and 3) that would have been ideal for mammoths (Agenbroad et al, 2005;Rick et al, 2012). The Channel Islands contain few terrestrial mammals and the precise timing of the appearance of island gray foxes (Urocyon littoralis), island spotted skunks (Spilogale gracilis), and island deer mice (Peromyscus maniculatus) is the subject of considerable debate.…”

Recent Progress, Trends, and Developments in Island and Coastal Archaeology

“…Nagaoka and Allen (2009) draw on research in New Zealand, which shows a clear case of human influence on extinction, but also one where other processes lead to the decline in concert with other forces (habitat alteration, climate). The complex nature of island extinctions was also noted by Jones et al (2008) for the California Coast, suggesting that the extinction of the flightless duck (Chendytes lawi) was protracted and followed millennia of human hunting (see also Rick et al 2012b). As scholars in Australia, the Caribbean, and California noted, some island fauna survived millennia of huntergatherer occupations, but went on to be decimated during the historic period (see Ainis and Vellanoweth 2012;Fitzpatrick and Keegan 2007;Walshe 2014).…”