Water dispersal of vegetative bulbils of the invasive exotic Dioscorea oppositifolia L. in southern Illinois

Journal of the Torrey Botanical Society
By: , and 

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Abstract

Riparian corridors promote dispersal of several species of exotic invasives worldwide. Dispersal plays a role in the colonization of exotic invasive species into new areas and this study was conducted to determine if the invasiveness of Dioscorea oppositifolia L. (Chinese yam) is facilitated by secondary dispersal of vegetative diaspores (bulbils) by water. Since seed production of this plant has not been observed in the United States, bulbils represent the only means of dispersal to new habitats. Dispersal was monitored by placing aquatic traps, tethered bulbils, and painted bulbil caches in a tributary of Drury Creek, Giant City State Park, Illinois. Results indicate that high-energy flow in the creek accelerated secondary dispersal of bulbils downstream and onto the floodplain. The longest recorded dispersal distance was 206.2 m downstream. Dispersal distance of tethered bulbils was not related to rainfall or flow velocity in the creek; however the total number of bulbils trapped was positively related to flow velocity. We conclude that secondary dispersal by water in streams can facilitate dispersal of vegetative bulbils of this exotic species.

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Publication type Article
Publication Subtype Journal Article
Title Water dispersal of vegetative bulbils of the invasive exotic Dioscorea oppositifolia L. in southern Illinois
Series title Journal of the Torrey Botanical Society
DOI 10.3159/1095-5674(2005)132[187:WDOVBO]2.0.CO;2
Volume 132
Issue 2
Year Published 2005
Language English
Publisher Torrey Botanical Society
Contributing office(s) National Wetlands Research Center, Wetland and Aquatic Research Center
Description 10 p.
First page 187
Last page 196
Country United States
State Illinois
Other Geospatial Drury Creek watershed, Giant City State Park
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