Climate and Diet of Mammoths in the East Siberian Arctic
Mammoths roamed the high Arctic region on Faddeyevskiy Island, Novaya Siberi archipelago (75°N, 143°E, 30m elevation), just prior to the height of the last ice age. Numerous mammoth (Mammuthus primigenious) bones collected within 5 km of the study site date to between 36,700 and 18,500 years ago. Rare bison (Bison priscus) bones date to 32,200 and 33,000 years old. In order to learn more about the environment and diet of the mammoths, scientists cut a 1.4m section from the frozen sediments. We carefully examined the samples in the laboratory. Radiocarbon dates of organic material in a sequence of clay and sandy frozen sediments indicate that the deposits accumulated during a relatively warm interval named the "Kargian", around 42,000 to 25,000 years ago. This warm interval (called an interstadial) also occurred in Eurasia and other parts of Siberia, as well as Alaska.
Today this area has a mean July temperature of about 2°C, mean January temperature of about -30 to -32°C, and a mean annual temperature of about 15°C. Total annual precipitation here is only 100-200 mm, with most of the precipitation during the summer. Snow thickness can be as much as 30 cm, and frost is present throughout the year. Because of this extreme climate, very few species of plants grow on the island today, at last count only 43 species! It is classified as high arctic tundra. Most of the species are grasses, herbs, and mosses.
Small samples of the frozen sediments were chemically treated in a paleoecology laboratory to isolate the pollen and spores, and carefully screened for macrofossils. The pollen signature in the sediments largely reflects tundra-steppe vegetation, which provided food for the mammoths. The vegetation was composed of grasses, sedges, and wormwood, but also included members of the rose, buttercup, and daisy family. This vegetation assemblage is not surprising for this region. What is really surprising is the fact that it apparently was several degrees warmer in summer than today during a period just prior to the last ice age, when sea level was still 30-40 m lower than present! We determined this estimate of climate change from macrofossils, which include sedge seeds. Today the distribution of these plants is highly correlated with the July 4°C isotherm. This means that the area was about two degrees warmer than it is today in summer, which also is consistent with results from other studies in adjacent areas of Siberia that show northward movement of the spruce and birch treeline into the tundra during the Kargian. At the end of this warm period, the mammoths probably moved southward, since few bones date to the height of the ice age on the island.
Climate change affects ecosystems today, as it has in the past. By exploring past climate change, its magnitude and rapidity, we obtain a basis to understand how future climate change may influence our environment. Plants are directly affected by climate, and vegetation changes in turn are important for animals that feed on them. If we can discover and understand the links between climate and ecosystems of the past, we have a better chance of understanding current change and predicting the future.
Andreev, A.A., D.M. Peteet, F. Romanenko, L. Filimonova, L.D. Sulerzhitsky, and P.E. Tarasov 2001. Late Pleistocene interstadial environment on Faddeyevskiy Island, East Siberian Sea, Russia. Arctic Alpine Res. 33, 28-35.
Please address all inquiries about this research to Dr. Dorothy Peteet.