Baghai-Riding, Nina , Corcoran, Maureen K. , Wrenn, John .
Japanese knotweed and other palynological inferences from soil cores in the Woonasquatucket River Valley, Rhode Island.
JAPANESE knotweed (Polygonum cuspidatum Sieb. & Zucc.), family Polygonaceae, was introduced to North America in the late 1800ís and is currently regarded as an invasive species. It is a giant dioecious herb, reaching heights of 2 to 3 m in spring and is abundant in wetland areas throughout the eastern United States. It blooms in late summer when wind and insects spread its pollen. The pollen is characterized by perforated double-layered columellae and an oblong pore in the equatorial region. Four dark brown to black, organic rich, palynology soil cores were collected on a raceway of a Revolutionary War Powder Mill located on the west bank of the Woonasquatucket River, Rhode Island. The powder mill built in 1776 to supply gunpowder to colonies during the Revolutionary War, exploded in 1779. The depths of the cores varied from 20 to 36 cm. They were underlain by glacial till estimated at 10,000 to 17,000 BP. Each core was sectioned into two-centimeter intervals, processed, and analyzed to document first occurrence of Japanese knotweed as an age marker. Well-preserved, historical, plant succession records are visible throughout the cores. Detailed palynological assessment made on core sample GM-04, for example, portrays an abundance of monolete spores in the basal six centimeters. Recovery weeds, arborescent angiosperms and bisaccate gymnosperms become increasingly important at higher intervals. Carbon spherules probably from the 1779 explosion were noted eight centimeters from the coreís top. Pollen grains of Japanese knotweed were rare but noted in the upper five to six centimeters. This factor may be attributed to the lack of overbank deposition, a process usually acting to preserve pollen from reduced flooding during the late summer or early fall when their pollen is most prolific, or possibly Japanese knotweed did not become well-established in the local area until recently.
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1 - Delta State University, Division of Biological & Physical Sciences, Cleveland, Mississippi, 38733, USA
2 - U.S. Army Engineer Research and Development Center Waterways Experimen, Vicksburg, Mississippi, 39180, USA
3 - Louisiana State University, Department of Geology and Geophysics, Baton Rouge, Louisiana, 70803, USA
Presentation Type: Poster:Posters for Sections
Location: Auditorium/Bell Memorial Union
Date: Tuesday, August 1st, 2006
Time: 12:30 PM