Dissertation Research: Paleoecology and Testing of Paleoclimate Hypotheses in Southern California During the Holocene

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9801449 Davis This proposal will establish a full-Holocene paleoenvironment record for the Southern California Mountain region. This record will be used to infer past climates for the regions and these, in turn, will be used to test simulations of past regional climates derived from mathematical global climate models. These tests are necessary to validate such models and their use in forecasting future climates. Fossil pollen preserved in mountain meadow sediments will be the primary indicator of past climate conditions. In addition, pollen data will be combined with charcoal, other plant fossils, and the physical characteristics of sediments to infer past conditions. Comparison of fossil pollen assemblages to those representative of model vegetation will be a primary method for analysis. Similar fossil and modern pollen data will be used to infer similarity in past and present vegetation, and therefore climate at a site. Initial pollen counts suggest that the early Holocene in S.Calif. Mountains was not much different than present-day conditions. This contrasts with the relatively dry conditions that have been inferred for the Sierra Nevada and Pacific Northwest and is consistent with climate-model simulation of enhanced monsoonal flow into the Southwest. The results of our analyses will improve the spatial resolution of the paleoenvironmental record in the Southwest.