Meeting Abstract
35.5 Tuesday, Jan. 5 Using the fossil record to test phylogeographic and ecological niche model hypotheses about the locations of glacial refugia MCGUIRE, JL*; DAVIS, E; ORCUTT, JD; Univ. of California, Berkeley; Univ. of Oregon; Univ. of Oregon mcguire@berkeley.edu
During the Last Glacial Maximum (LGM), continental ice sheets covered much of the northern portion of North America, reducing land area and altering climate regimes. As a result, plant and animal species were forced to shift their ranges to adjust to these conditions. Phylogeographic methods and ecological niche models (ENMs) have both been used model the ranges of plants and animals during the LGM. Phylogeographic efforts have focused on interpreting area cladograms based on the lineage structures of populations, with the assumption that each living population of temperate species has spread from a refugium since the LGM. ENMs apply environmental constraints derived from current species ranges to reconstructed LGM climate maps to determine the regions where the organisms could have lived in the past assuming niche conservatism. We have used fossil data compiled in the FAUNMAP II database to test the reconstructed glacial refugia of six small mammal species: Blarina brevicauda, Glaucomys sabrinus, Glaucomys volans, Lepus arcticus, Martes americana, Myodes (Clethrionomys) gapperi. Due to limitations in the FAUNMAP II database, we were unable to include Canada or Mexico in our analyses. When we compared refugial hypotheses from both phylogeographic and ENM reconstructions to the ranges of these species’ fossils, we found mixed agreement with the hypotheses. LGM fossil specimens from two of the species (G. sabrinus and G. volans) were found outside of refugial ranges as predicted by both phylogeographic and ecological niche methods. Although many of the species ranges agree in some regards with either ecological niche or phylogeographic hypotheses, no clear pattern could be found regarding whether either method accurately predicted LGM refugia.
