The extent to which invasive aquatic plants move via accidental inclusion in aquatic plant orders or sale of prohibited species is unknown. Forty orders were placed to 34 aquatic plant vendors across the US between May and September 2001 to determine the prevalence of movement into Minnesota via horticultural trade. Federal noxious weeds or Minnesota prohibited exotic species were acquired 92% of the time they were ordered and included Alternanthera sessilis, Butomus umbellata, Hydrocharis morsus-ranae, Potamogeton crispus, and Lythrum salicaria. Ninety three percent of orders received from aquatic plant vendors contained a plant or animal species not specifically requested; 10% of these purchases contained federal noxious weeds or Minnesota exotic species. Lemna minor was the most common incidental receipt found per taxa and per purchase, although Hydrilla verticillata, Lythrum salicaria, Salvinia molesta, and Potamogeton crispus (all prohibited taxa) were also found. Misidentified plants were found in 18% of the orders; unordered seeds in 43%. The sale and transport of prohibited aquatic plants likely presents the greatest risk associated with the aquatic plant trade. Other important factors include misidentification leading to the unintentional sale of invasive plants and the incidental inclusion of species during translocation.
Bibliographical noteFunding Information:
We thank the Minnesota Department of Natural Resources for all of their time and advice given to this project. We also thank Jill Packovsky Craig and Napoleon Genereux for their help in the greenhouse, and Dr. Neil Anderson, Jay Rendall, Chip Welling, and Dave Wright for their comments on the manuscript. The project was funded by a grant from the Minnesota Department of Natural Resources and Minnesota Sea Grant.
Copyright 2008 Elsevier B.V., All rights reserved.
- Aquatic weeds
- Exotic species
- Introduction pathways
- Water gardening