SUSTAINED RESTORATION OF PHRAGMITES-INFESTED WETLANDS: A VEGETATION ALTERNATIVE TO CYCLIC SPRAY AND BURN


t the present time, restoration of low salinity Phragmites-dominated marshes to desired plant species is based on a protocol of two years of spraying in early fall with Rodeo, followed each year by an early spring burn of the dead canes. Desired species often colonize the site and persist for many years unless re-invasion by Phragmites occurs during early establishment phases. When re-infestation happens the usual solution is to repeat the spray and burn cycles, however in some situations cyclic spraying is not possible. In any case, cyclic restoration, with its resultant "down years" during the spray and burn period, results in the loss of desired wetland functions for living aquatic resources, and has economic and ecological shortcomings. Usually Phragmites re-invades via one of three routes: a) from the upland to the marsh plain vegetatively by rhizomes or stolons, b) from other marshes as pieces of vegetative material carried by the tide and stranded on "high spots" in the marsh where it can root and grow, or c) from seeds that are transported by the wind or tidal water to "high spots" in an otherwise rather low marsh plain. Once established in a favorable habitat, Phragmites can grow down into lower sites where it could not initially become established. The strategy for control measures proposed here relies on the development of varieties of desired species (valuable for living aquatic resources) that can block the re-invasion of Phragmites and subsequently planting the varieties at key points.

Funding Source: Public Service Electric & Gas Company, Hancocks Bridge, NJ and NOAA Sea Grant.

Phragmites australis and Juncus roemerianus

Phragmites australis can be seen in the background and Juncus roemerianus, a potential Phragmites-blocker, in the foreground.



Dr. Denise Seliskar

Dr. Denise Seliskar

 

Halophyte Biotechnology Center

Dr. John Gallagher

Dr. John Gallagher


May 17, 2010
Questions/comments contact: connie@udel.edu