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|Title:||Potential use of native aquatic plants for long-term control of problem aquatic plants in Guntersville Reservoir, Alabama. Report 2, Competitive interactions between beneficial and nuisance species|
|Authors:||Aquatic Plant Control Research Program (U.S.)|
Doyle, Robert D. (Robert Donald)
Smart, R. Michael.
Aquatic plant management
Establishment of native macrophytes
Littoral zone restoration
|Publisher:||Environmental Laboratory (U.S.)|
Engineer Research and Development Center (U.S.)
Abstract: Aquatic plant species that form dense floating canopies or mats at water surface often negatively impact the ecological and economic values of a water body. In Guntersville Reservoir, this growth form is exhibited by both the weedy, nonnative aquatic macrophyte Myriophyllum spicatum (Eurasian watermilfoil) and the nuisance, albeit native, mat-forming cyanobacteria Lyngbya wollei (lyngbya). In contrast to the few species that cause problems, most native aquatic plant species exhibit growth forms that enhance water quality and/or habitat values of the aquatic systems. In addition, greenhouse and pond research have indicated that established populations of native aquatic plants serve to minimize or prevent establishment of less desirable species. This report presents results of field trials designed to test the central hypothesis that small populations of native plants, deliberately established in areas experiencing or subject to infestation by one of the two nuisance species in Guntersville Reservoir, are able to survive and ameliorate the negative impacts of nuisance species. One aspect of this research examined the ability of established plots of three native species to withstand reinvasion by M. spicatum. Small plots of the native submersed species Vallisneria americana (wild celery), the floating-leaved species Potamogeton nodosus (American pondweed), and the floating-leaved/emergent species Nelumbo lutea (American lotus) were established during a general decline of M. spicatum in Guntersville Reservoir. This offered the opportunity to examine the potential of these species for preventing reinfestation of M. spicatum as it regrew within the reservoir. Although establishment of the natives was complicated by high herbivory pressures, results indicate that established plots of V. americana and N. lutea significantly reduced the regrowth of M. spicatum relative to unplanted control plots. In contrast, P. nodosus was not effective at preventing regrowth of M. spicatum. However, failure of this floating-leaved species to effectively compete with M. spicatum in this study may have resulted from the small plot size used. A second aspect of this research investigated the ability of the native emergent macrophyte Pontederia cordata (pickerelweed) and of the floating-leaved species P. nodosus to minimize the negative impacts of L. wollei. This research indicated that, when well-established, both species were effective at redistributing the mass of L. wollei and preventing the formation of the nuisance floating mat during the summer period, offering immediate relief for the most noxious of the many negative characteristics of the mats. In addition, P. cordata growth changed the environmental conditions where it grew by reducing incident light and sediment nutrients available to the L. wollei mats. These and perhaps other changes to the environment caused by establishment of this macrophyte significantly reduced the mass of L. wollei within the vegetated plots. Establishment of P. cordata may offer an effective, longterm control for L. wollei.
|Appears in Collections:||Technical Report|