Paradigms and proboscideans in the southern Great Lakes region, USA

The mobility and dietary preferences of now‐extinct proboscideans have not been comprehensively examined in the central USA. We used stable carbon (δ13C), oxygen (δ18O) and strontium (87Sr/86Sr) isotopic signatures in molar enamel to investigate the foraging ecology of four mastodons (Mammut americanum) and eight mammoths (Mammuthus spp.) from southwestern Ohio and northwestern Kentucky. We tested two hypotheses: (i) these individuals were nomadic migrants that were passing through the region when they died; and (ii) mammoths and mastodons foraged in different environments. Unexpectedly, our results suggest that 11 of the 12 sampled individuals were regional residents. With the exception of one mastodon, 87Sr/86Sr ratios for proboscideans and regional water samples were statistically indistinguishable; slightly lower ratios for waters suggest glacial loess has an impact on modern samples. Amongst the individuals identified as residents, 87Sr/86Sr ratios indicate that mammoths and mastodons foraged in discrete geographical areas, and δ13C values imply dietary differences between the genera, which is consistent with our expectations. Oxygen isotope values may be able to distinguish animals that lived during the Last Glacial Maximum (LGM) from those that lived more recently. Three mammoths and one mastodon yielded δ18O values that are similar to modern regional precipitation and surface water, but too high for estimated drinking water during the LGM. We propose that these individuals lived during a relatively warm period following the LGM. Compellingly, the mammoth with the highest δ18O value also has the lowest δ13C value, suggesting that this individual was alive after regional vegetation shifted from open parkland to deciduous forest dominated by C3 species. Our results demonstrate that a wealth of information can be gleaned from fossil museum specimens and lay a foundation for future work on the foraging ecology of proboscideans and other extinct megafauna from the Midwest USA.

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“…; Saunders et al . ). Mixed‐hardwood forest probably dominated the entire region when these individuals were alive (Wilkins et al .…”

Section: Discussionmentioning

confidence: 97%

“…Little is known about the mobility of mammoths or mastodons in the central USA, which was a key geographical area for both genera during the Late Pleistocene (Fisher ; Saunders et al . ; Miller & Bahn ).…”

mentioning

confidence: 99%

Stable isotopes reveal ecological differences amongst now‐extinct proboscideans from the Cincinnati region, USA

Baumann

Crowley

2014

Boreas

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“…Modeling efforts that use pollen records from central North America leave much room for interpretation of temperature or precipitation regimes but do tend to agree that the YD had a climate distinct from the B/A and PB (Shane and Anderson 1993, Shuman et al 2002). An abrupt decrease in ash pollen and increase in spruce pollen near the 12.9-ka YD boundary suggests that cooler conditions generally presided over the Midwest to the east of our collection area (Shane and Anderson 1993, Shuman et al 2002, Saunders et al 2010. Within the dating accuracy of the proxies, reduction in oak deposition in MO was coeval with pollen-based estimates of reduced summer temperatures across the Midwest at the B/A to YD boundary (Fig.…”

Section: Comparisons Of Oak Anatomy and Deposition With Other Paleoclmentioning

confidence: 87%

“…A review of paleoclimate data led Yu and Wright (2001) to infer that shifts in atmospheric circulation patterns propagated across mid-continental North America but the mechanisms, timing, and extent of these effects remain uncertain. More recent proxy evidence from the American mid-continent has shed light on the timing and complexity of vegetation dynamics over the Great Plains and Midwest during the late Quaternary, but evidence has still been elusive for widespread changes in temperature, its seasonality, and associated patterns in wetness or aridity during the YD (Denniston et al 2001, Haynes 2008, Nordt et al 2008, Gill et al 2009, Dorale et al 2010, Saunders et al 2010.…”

Section: Introductionmentioning

confidence: 99%

Spring temperature responses of oaks are synchronous with North Atlantic conditions during the last deglaciation

Voelker

Noirot-Cosson

Stambaugh

et al. 2012

Ecological Monographs

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Paleoclimate proxies based on the measurement of xylem cell anatomy have rarely been developed across the temperature range of a species or applied to wood predating the most recent millennium. Here we describe wood anatomy‐based proxies for spring temperatures in central North America from modern bur oaks (Quercus macrocarpa Michx.). The strong coherence of temperature signals across the species range supports the use of these proxies across thousands of years of climatic change. We also used 79 subfossil oak log cross sections from northern Missouri, 14C‐dated to 9.9–13.63 ka (ka is 1000 cal yr BP), to assess the frequency of oak deposition into alluvial sediments and a subset of these oaks for a wood anatomy‐based reconstruction of spring paleotemperatures. Temperatures during the Younger Dryas cold period (YD) were up to 3.5°C lower than modern temperatures for that region, equivalent to or lower than those experienced at the northern edge of the modern species range. Compared to extant oaks growing at much higher [CO2], subfossil oaks had greater vessel frequencies. Besides very low theoretical (or estimated) xylem conductivity near the beginning of the oak record near 13.6 ka, vessel frequencies greater than modern trees compensated for reduced vessel dimensions so that theoretical xylem conductivity was consistently above that of modern trees at the cold northern sites. Significant correlations were found between the frequency of 14C‐dated oaks and either δ18O from the NGRIP (North Greenland Ice Core Project) ice core or from the Cariaco grayscale marine‐sediment record from the southern Caribbean sea. Oak deposition into alluvial sediments during the YD was significantly lower than expected given the average sample depth of oaks from 9.9 to 13.6 ka. Reduced oak deposition during the YD suggests that an abrupt shift in climate reduced oak populations across the region and/or changed the rates of channel movement across drainages.

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“…On theoretical grounds, Saunders et al (2010) suggested that submerged aquatic plants available to the Brewster Creek mastodon (Illinois) would have had higher δ 13 C values than terrestrial plants because of dissolved limestone in local water bodies. If we assume that aquatic plants had higher δ 13 C values than terrestrial plants in Ontario around 12,400 14 C yr BP (ca.…”

Section: General and Seasonal Environmental Changes Over Timementioning

confidence: 99%

Environmental change and seasonal behavior of mastodons in the Great Lakes region inferred from stable isotope analysis

Metcalfe¹,

Longstaffe²

2014

Quat. res.

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We investigate seasonal variations in the diet and drinking water of four Great Lakes mastodon (Mammut americanum) specimens using stable isotope analysis of serially sampled inner-enamel bioapatite structural carbonate (δ 13 C sc , δ 18 O sc ), and previously published bulk analyses. Isotopic analyses and thin section measurements showed that mastodon tooth enamel extension rates (~12-4 mm/yr, decreasing toward the cervix) were lower than those of mammoths or modern elephants. Mastodons had distinct and highly regular seasonal variations in δ 13 C sc and δ 18 O sc , which we interpret in the context of local glacial history and vegetation changes. Seasonal variations in δ 18 O were large but variations in δ 13 C were small, and may have been obscured if coarser sampling methods than our inner-enamel sampling approach were used. Thus, our approach may be particularly useful for understanding relatively small seasonal changes in δ 13 C within C 3 environments. The seasonal patterns, though not entirely conclusive, suggest that the Ontario mastodons did not migrate over very long distances. Rather, the climate and seasonal dietary patterns of mastodons within the region changed over time, from 12,400 to 10,400 14 C yr BP (~15,000 -12,000 cal yr BP). Insights gained using these methods can contribute to a better understanding of megafaunal extinctions and Paleoamerican lifeways.

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Paradigms and proboscideans in the southern Great Lakes region, USA

Cited by 43 publications

References 33 publications

Stable isotopes reveal ecological differences amongst now‐extinct proboscideans from the Cincinnati region, USA

Stable isotopes reveal ecological differences amongst now‐extinct proboscideans from the Cincinnati region, USA

Spring temperature responses of oaks are synchronous with North Atlantic conditions during the last deglaciation

Environmental change and seasonal behavior of mastodons in the Great Lakes region inferred from stable isotope analysis

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