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McCauley, Ross [1].

The story of a hoboing plant – tracking range expansion of Froelichia gracilis (Amaranthaceae) using historical herbarium records and geographic information systems..

Froelichia gracilis (Hook.) Moq. is a small weedy annual (rarely perennial) herb native to the southern Great Plains and the southwestern United States and adjacent Mexico. Today, F. gracilis is found extensively throughout the eastern U.S. and as far north as southern Ontario. In conjunction with a revision of the genus in North America, over 1000 specimens of F. gracilis from 21 American and European herbaria were consulted and location information used to track expansion of the species range between the years 1900 and 2000. It was found that prior to 1900 the range was restricted to west of the Mississippi River. Initial eastward expansion began with long-distance human mediated dispersal to major industrial and transportation centers near Boston, western New York, and eastern Pennsylvania. Later expansion into the Midwest, particularly the industrialized region south of Lake Michigan occurred by mid-century. This expansion of range east of the Mississippi River has been mediated by railroads that serve to transport the seeds and provide a suitable habitat in ballast, mimicking the poor soils of the species’ native habitat in dry hillsides, short-grass prairie, and gravel alluvia. This association with railroads is exemplified by over 90% of all eastern collections being made from railroad ballast. Some recent collections, particularly from the Mid-Atlantic and southeastern states do indicate a recent expansion into less human disturbed areas, principally pine and oak woodlands on sandy soils. This colonization of native habitats indicates the potential invasiveness of F. gracilis, although field observations indicate that its ability to invade beyond the margins of woodlands may be rather limited.

1 - Ohio University, Department of Environmental and Plant Biology, Porter Hall, Richland Avenue, Athens, Ohio, 45701-2979, USA

Keywords:
Amaranthaceae
GIS
invasive species
Froelichia.

Presentation Type: Poster
Session: 32-148
Location: Special Event Center (Cliff Lodge)
Date: Tuesday, August 3rd, 2004
Time: 12:30 PM
Abstract ID:1012