Lower-latitude mammals as year-round residents in Eocene Arctic forests
- 1University of Colorado Museum and Department of Geological Sciences, University of Colorado, Boulder, Colorado 80309, USA
- 2Department of Geology, Colorado College, Colorado Springs, Colorado 80903, USA
- 3Department of Geology and Geological Engineering, Colorado School of Mines, Golden, Colorado 80401, USA
Abstract
The Arctic is undergoing rapid warming, but the impact on the biosphere, in particular on large terrestrial mammals, is not clear. Among the best deep time laboratories to assess biotic impacts of Arctic climate change, early Eocene (ca. 53 Ma ago) fossil assemblages on Ellesmere Island, Nunavut (~79°N), preserve evidence of forests inhabited by alligators, tortoises, and a diverse mammalian fauna most similar to coeval lower-latitude faunas in western North America. By analyzing carbon and oxygen isotope ratios of mammalian tooth enamel, we show that large herbivores were year-round inhabitants in the Arctic, a probable prerequisite to dispersal across northern high-latitude land bridges. If present-day warming continues, year-round occupation of the Arctic by lower-latitude plants and animals is predicted.
Footnotes
-
↵GSA Data Repository item 2009119, details of sample preparation, isotope analyses, and diagenesis; tables of stable isotope data from bulk samples of Arctic Coryphodon and perissodactyls, as well as sequential samples of Arctic Coryphodon; and Fig. DR1 (changes in seasonal range in δ18O of precipitation with latitudinal differences), is available online at www.geosociety.org/pubs/ft2009.htm, or on request from editing{at}geosociety.org or Documents Secretary, GSA, P.O. Box 9140, Boulder, CO 80301, USA.
-
- Received 29 October 2008.
- Revision received 29 December 2008.
- Accepted 15 January 2009.
- © 2009 Geological Society of America
