Paleoenvironmental implications of two relative indicator rodent taxa during the Pleistocene to Holocene transition in south-eastern Washington state, USA.

ABSTRACT Local pollen data, diminution of body size of three ungulate species, and decreased mammalian richness and evenness all indicate grass decreased in abundance during the Pleistocene-Holocene transition (PHT) in eastern Washington state, USA. This paleoenvironmental history suggests that the abundance of remains of Microtus sp. should decrease as remains of Peromyscus maniculatus increase in abundance during the PHT. These two taxa have well-known ecologies relative to one another. PHT sediments at the Marmes archeological site in south-eastern Washington state are sorted into three chronologically sequent, isotaphonomic analytical units. Relative abundances of remains of Microtus sp. and P. maniculatus shift across the analytical units in the predicted manner whether raw abundances or rarified abundances are considered. These results suggest relative abundances of remains of Microtus sp. and P. maniculatus recovered from other sites may be used as relative indicators of paleohabitats. Their abundances at Homestead Cave, Utah, shift as predicted from the Late Pleistocene through the Early Holocene. [ABSTRACT FROM AUTHOR]