NRCS and Partners Plant Native Species to Reduce Growth of Non-native Plants at the Awcomin Salt Marsh in Rye, New Hampshire

A project, started in 2001 to remove up to 95,000 cubic yards of fill that was dumped on the Awcomin Marsh from the dredging of Rye Harbor between 1941 and 1962, was completed in 2005. This past summer, Brooke Smart, NRCS District Conservationist and Project Leader, Kim McCabe, Sandy Sears, Jeff Tenley, Keri Neal, and Don Keirstead of the NRCS, along with Gregg Moore and Dave Burdick, Salt Marsh Ecologists from the University of New Hampshire Jackson Laboratory, the Rockingham Counting Conservation District, Ted Diers, Kevin Lucey and Frank Richardson of the NH Department of Environmental Services, and volunteers from the University of New Hampshire, planted native species of Spartina pectinata (cord grass) to protect against the further invasion of non-native plants. 

To better understand salt marsh soils and salinity patterns prior to planting, NRCS and UNH developed a new technique for quickly collecting thousands of georefrenced salinity readings from the upper 75 cm of the soil profile using Electromagnetic Induction (EMI) technology. Using an Inverse Distance Weighted modeling technique spatial trends in pore water salinity were produced.  This tool furthered understanding of the limits of invasion of established colonies of Phragmites and also helped determine future salt marsh community types in restored marshes such as Awcomin.

Because brackish salt marsh communities are in greater danger of invasion from Phragmites australis (Phragmites), aggressively planting areas where tidal fresh and brackish conditions exist provides insurance against Phragmites colonization.  Areas near Gammon Brook and the western part of the excavated areas have low salinities and were at greatest risk for Phragmites colonization. The NRCS Big Flats Plant Materials Center, in Big Flats, NY provided 8,000 cord grass plants collected from North Hampton, New Hampshire and propagated at the center.