The project was sponsored by Salem Sound Coastwatch in conjunction with Salem State College, under a City of Salem Conservation Commission Order of Conditions.

In this Pilot Project, SSCW partnered with Salem State College (SSC) to experiment with three different methods to eradicate the invasive common reed, Phragmites australis,in a half-acre perched marsh in Pickman Park, Salem, MA. The marsh contains three distinct stands of Phragmites. Because of the distinct elevations and hydrological characteristics of the stands, SSCW and SSC tested a different control method in each stand. SSC students monitored the salt marsh vegetation and salinity.

Phragmites australis is a serious threat to wetlands. Phragmites invasions generally begin as small stands at the edge of wetlands. Controlling emerging stands may help to reduce the spread of this invasive plant. Protecting the remaining salt marshes of Salem Sound is critical for the ecological health of the Sound. Two-thirds of the Sound’s salt marshes were lost between 1965 and 1998 (Chase et al. ). Salem Sound’s remaining 65 acres (30 acres of which are in the Forest River system) are predominately small or fringe salt marshes in close proximity to roads, homes, and influxes of freshwater and sediment runoff, locations where Phragmites finds it easy to establish.

GOALS:

1. Document methods to remove small stands of Phragmites before wetlands become phragmites monocultures
2. Involve college students in environmental research
3. Share this phragmites control information with conservation agents/commissions and private landowners.

OBJECTIVES:

1. Use three different control methods on the three discrete stands of Phragmites in the study marsh. See Methodology
2. Provide college students direct field experience with wetland restoration.

Two Salem State College professors used the study to expand their curriculas. Between 2006 and 2008, eighty-four college students under the direction of Dr. Young, SSC Biology Department, monitored salt marsh vegetation. Five of his students worked during the summers to employ methods 1 and 2 and monitored salinity and vegetation in the marsh. One student is currently analyzing the results. Nineteen students under the direction of Dr. Luna, SSC Geography Department, mapped the wetland and the pre and post-restoration phragmites areas using GPS technology.

3. Share the study results and conclusions with the public.

SSCW has prepared a PowerPoint presentation (1.2MB PDF) for 5th – 10th grade students that covers salt marsh ecology and Phragmites. Please let us know if you would like to learn more about this project and the invasive Phragmites or have the PPT with curriculum notes. SSCW also speaks at neighborhood and other groups.

METHODOLOGY
Baseline data were collected during the summer of 2006 for the marsh vegetation and salinity. SITE MAP

Method 1: cut and increase salinity through tidal flow.
In 2007, Area 1 Phragmites, those closest to the tidal river in the southwest corner, were cut weekly from early June through mid August, than bi-weekly until the end of the growing season. In December 2007, the concrete wall separating the river from the marsh was breached and a ditch dug into the marsh to increase tidal inundation. The ditch is approximately 20 feet in length and 2 feet wide by 1 foot deep. Cutting was biweekly in 2008 over the same time period.

Method 2: cut and apply BurnOut II
The higher elevation of Area 2 eliminated the possibility of increasing salinity from tidal flow. SSC students followed the same cutting schedule as with Method 1 and BurnOutII sprayed on the cut stalks at same time as cutting in 2007 and 2008. A single clearing of cut stalks took place in late summer.

Method 3: excavate wetland to increase tidal inundation
The largest stand of Phragmites was at the back of the wetland and the greatest distance from the river. Sandwiched between the toe of an upland slope and a tidal ditch, Area 3 required wetland alteration. A perimeter 2 feet by 2 feet ditch was dug around the back of the Phragmites stand. The Phragmites dominated area between the new ditch and old ditch was excavated to lower the elevation by 6 inches to increase tidal inundation. The old ditch was left undisturbed. After the excavated earth was dewatered it was removed offsite to an upland area.

Northeast Wetland Restoration (Geoff Wilson, Berwick ME) was contracted to dig the new ditch and excavate the phragmites stand. The excavation work took place from August to December in 2007. Timber matting was used to reduce the impact of the small excavator (TBO45) on the marsh to approximately 1 lb. per square inch of pressure.

Results/Lessons Learned

All activities of the grant to restore one-half acre of salt marsh by the removal of Phragmites have been completed. Control Methods 1 and 2 have been implemented in their respective areas for two full growing seasons, and one summer has passed since the excavation Method 3 was applied to the back Phragmites stand to increase tidal flow. Pre and post-restoration monitoring has taken place and is currently being analyzed.

Complete removal of Phragmites is a difficult challenge. The greatest success in removing Phragmites came in Area 1 where the breach in the wall increased saltwater intrusion. In the elevated Area 2, Phragmites have been removed from the center of the area but plants still remain at the edges. In Area 3, the Phragmites in the excavated site experienced stunted growth during the 2008 summer (average maximum height of 143.4 cm (4.7 ft.) in 2008 compared to 246.1 cm (8.1 ft.) in 2006), despite frequent rains throughout the 2008 summer which provided ideal growing conditions for Phragmites.

Results Report - coming in December 2008 ( MB PDF)

An unanticipated challenge arose during this project, which affected Area 2 directly. In 2007, the abutting property, a capped landfill owned by Salem State College, became a major construction project to build a baseball field. The construction site fencing and erosion barriers were in place before Northeast Wetland Restoration was able to begin the Phragmites excavation. This limited the marsh access and it was necessary to cross Area 2. This resulted in the compaction of Area 2 and substantial disturbance to the Phragmites stand being studied with Method 2. Therefore, even though the Phragmites have been reduced in this area, it is impossible to conclude that cutting and applying BurnOut was responsible

The partnership between SSCW and SSC will continue at this site. Plans have been made to continue monitoring the marsh and studying the presence/absence and condition of the Phragmites. SSCW will continue to use this site as lessons learned for phragmites control, to involve college students in environmental research, and to share Phragmites control information with conservation agents/commissions and private landowners.
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PHOTOS of the Project

Pre and post comparison photos (864 KB)

Pickman Project Sign (106 KB)