The Pleistocene biogeography of eastern North America: A nonmigration scenario for deciduous forest

Technical Report · Thu Dec 31 04:00:00 EST 1998

DOI:https://doi.org/10.2172/564104· OSTI ID:564104

Loehle, C ^[1]; Iltis, H ^[2]

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1. Argonne National Lab., IL (United States). Environmental Research Div.
2. Univ. of Wisconsin, Madison, WI (United States). Dept. of Botany

The current reconstruction of the vegetation of eastern North America at the last glacial maximum postulates a very wide zone of tundra and boreal forest south of the ice. This reconstruction requires that the deciduous forest retreated far to the south. The authors believe that this reconstruction is seriously in error. Geologic evidence for glacial activity or tundra is absent from the southern Appalachians. Positive evidence for boreal forest is based on pollen identifications for Picea, Betula, and Pinus, when in reality southern members of these genera have pollen that cannot be distinguished from that of northern members. Further, pollen of typical southern species such as oaks and hickories occurs throughout profiles that past authors had labeled boreal. Pollen evidence for a far southern deciduous forest refuge is lacking. Data on endemics are particularly challenging for the scenario in which deciduous forest migrated to the south and back. The southern Appalachian region is rife with endemics that are often extreme-habitat specialists unable to migrate. The previously glaciated zone is almost completely lacking in endemics. Outlier populations, range boundaries, and absence of certain hybrids all argue against a large boreal zone. The new reconstruction postulates a cold zone no more than 75--100 miles wide south of the ice in the East.

• Research Organization: Argonne National Lab., IL (United States)
• Sponsoring Organization: USDOE Office of Energy Research, Washington, DC (United States)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 564104
• Report Number(s): ANL/ER/PP--90468; ON: DE97008109
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
CLIMATIC CHANGE
ENVIRONMENTAL IMPACTS
FORESTS
NORTH AMERICA
NUMERICAL DATA
PLEISTOCENE EPOCH
POPULATION DYNAMICS
TERRESTRIAL ECOSYSTEMS