Biogeographic Patterns of Late Quaternary Mammals in the United States.

Poster presented at the:
54th annual meeting of the Society of Vertebrate Paleontology, Seattle, Washington. Oct 19-22, 1994;

1995 Midwest/Great Lakes ARC/INFO User Conference, Champaign, Illinois.

R. W. Graham, M. A. Graham, E. K. Schroeder, and R. S. Toomey -- Illinois State Museum, Springfield

Ernest L. Lundelius, Jr., University of Texas, Austin


FAUNMAP, an electronic database for the late Quaternary distribution of mammal species in the United States, has been used to assess evolution of mammalian communities in fluctuating environments. Maps illustrating changes in distributions of individual species document an individualistic response with species migrating in different directions, at different rates, and at different times. Low frequencies (<15%) of species pairs that are positively associated in both late Pleistocene and late Holocene faunas also support an individualistic hypothesis and refute the contention of tightly linked and highly coevolved species associations. TWINSPAN clustering scores plotted on a map of the United States reveal temporal biogeographic patterns. Geographic differentiation in the U.S. is similar for both the late Pleistocene and late Holocene, but the species composition of biogeographic regions differs for these two time periods. Finally, Dice similarity coefficients decrease with geographic distance of comparisons for both late Pleistocene and late Holocene, but for distances up to 1600 km, late Pleistocene values are always significantly lower than those of the late Holocene. This suggests that the late Pleistocene was more heterogeneous.

© Illinois State Museum -- Last updated 04-Sep-96 by Erich Schroeder