| Abstract: | Submersed aquatic vegetation, dominated by Vallisneria americana Michx., declined dramatically in Lake Onalaska (Navigation Pool 7, on the Upper Mississippi River) following drought conditions in the late 1980s. Coinciding with the decline were marked increases in the abundance of phyllum spicatum L., particularly in areas vacated by A. americana. Recent evidence indicates that much of the lake has remained unvegetated, but that since 1994, beds of V. americana have made a partial recovery. While the production of vegetative propagules may largely account for increases in populations of both species, the extent to which seed production may contribute to their expansion in the lake is unknown. To assess the germination potential and distribution of the aquatic macrophyte seed bank in Lake Onalaska, sediment cores (5 cm deep) were collected from 74 sampling sites in July 1996. Seedling emergence from sediments was observed in an environmental growth chamber operated at 25 C and a 14-hr photoperiod over a period of eight weeks. Fifteen species of aquatic macrophytes germinated in sediments from 55 sites. V. americana seedlings emerged from sediments from 36 sites throughout the lake, but were most prevalent in sediments collected within or downstream (within 250 m) of established V. americana beds. Seedlings of M. spicatum emerged from only two collected sediments that had supported this species in protected areas. These findings suggest that seed production may play a greater role in the dispersal of V. americana than M. spicatum, and further emphasize basic differences in their survival strategies, particularly in flowing water systems. |
| Genre: | Article |
| ProdID: | 1003515 |
| Citation Author: | Mcfarland, D. G.; Rogers, S. J. |
| Citation Contributing Office: | Upper Midwest Environmental Sciences Center |
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| Citation End Page: | 39 |
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| Citation Language: | English |
| Citation Larger Work Title: | Journal of Aquatic Plant Management |
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| Citation Number Of Pages: | 7 |
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| Citation Phsyical Description: | pp. 33-39 |
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| Citation Public Comments: | ISI:000074549400009 |
| Citation Publisher: | Aquatic Plant Management Soc, Inc. |
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| Citation Search Results Text: | The aquatic macrophyte seed bank in Lake Onalaska, Wisconsin; 1998; Article; Journal; Journal of Aquatic Plant Management; Mcfarland, D. G.; Rogers, S. J. |
| Citation Start Page: | 33 |
| Citation Volume: | 36 |
| Citation Year: | 1998 |
| Type: | citation/reference |
| Text: | The aquatic macrophyte seed bank in Lake Onalaska, Wisconsin; 1998; Article; Journal; Journal of Aquatic Plant Management; Mcfarland, D. G.; Rogers, S. J. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Thu, 1 Jan 1998 00:00 -0600 |
| Publisher: | Aquatic Plant Management Soc, Inc. |
