Taxonomic composition and body-mass distribution in the terminal Pleistocene mammalian fauna from the Marmes site, southeastern Washington state, U.S.A.

Mean adult body mass of mammal taxa is a fundamental ecological variable. Variability in the distributions of body masses of a mammal fauna suggest variability in habitat structure. Mammal remains from the Marmes archaeological site in southeastern Washington State date between 13,200 and 10,400 b.p., during the Pleistocene–Holocene transition (PHT). Known environmental history prompts the expectations that the Marmes PHT mammal remains should represent greater species richness and a larger array of body-mass sizes than modern faunas in the Marmes locale and in open shrub-steppe habitats, and lower species richness and a smaller array of body-mass sizes than modern faunas in closed forest habitats; species richness and the array of body-mass sizes should be similar to that for a mixed habitat of cool shrub-steppe with scattered conifers. The Marmes PHT cenogram meets these expectations. Body-mass clumps displayed by the Marmes PHT mammal fauna fall between those of closed forests and op...