Phylogeography of northern North America with insights from paleontological, geological, and molecular data
Gavin, Daniel .
Paleoecological evidence of the controls of forest composition and the late Holocene development of the interior wet-belt forests of eastern British Columbia.
Paleoecological studies of forest composition, developed from pollen and macrofossil stratigraphic sequences in lake sediment, are commonly analyzed over large site networks to reconstruct distributions of common tree species. Such paleoecological syntheses often address biogeographic responses to the major climate changes following deglaciation. However, because small populations are difficult to detect in the fossil record, there are major limitations in using fossil data to determine the presence or absence of particular taxa. Phylogeographic studies that identify the locations of glacial refugia are beginning to fill the gaps missing in the pollen records and greatly inform our understanding of post-glacial biogeography. But paleoecological methods are also becoming more sophisticated and can reveal the ecological, climatic, and landscape context of taxa that may have persisted within refugia. Together, paleodata and genetics of extant populations can show the capacity for certain taxa to endure harsh climatic conditions. A region with a particularly dynamic post-glacial record is the interior wet belt of the northern Rocky Mountains, which was entirely glaciated except for a small refugium in northern Idaho. A network of paleoecological and paleoclimate studies is revealing that widespread mesic conditions in this region existed for less than 4000 years and that fire and drought had major effects on limiting development the wet-belt forest type. Furthermore, tree species that today define the extent of the welt belt first became abundant in northern, glaciated, regions. This suggests that small populations were important not just for in situ persistence in refugia, but also during a range expansion of more than 600 km under marginally suitable climatic conditions.
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1 - University of Oregon, Department of Geography, 1251 University of Oregon, Eugene, OR, 97403, USA
Presentation Type: Symposium or Colloquium Presentation
Location: Room 4/Woodward
Date: Monday, July 28th, 2008
Time: 8:45 AM