Seagrass - Salt
Marsh - Anadromous
Seagrass beds can be restored by encouraging natural
recolonization in areas that have experienced improvements in surface
water quality. Proactive methods of eelgrass restoration include
transplanting of individuals taken from healthy donor beds or seedlings
reared under laboratory conditions. In some cases seeds can be planted
or broadcast. Seeding can be used alone, or in concert with transplant
techniques. Several technical
guidance documents have been published to assist restoration
practitioners in selecting transplant sites, and in choosing appropriate
restoration methods for eelgrass beds.
Natural Recolonization |
Transplants | Seeding
|Eelgrass bed below the water surface.
This approach to eelgrass restoration focuses on water
quality improvement in the study area with the assumption that once
suitable conditions are established, seagrass will naturally re-colonize.
This approach involves a long-term coordinated effort to upgrade
municipal sewage systems, and a program to identify and curtail
point and non-point discharges from industrial, residential and
agricultural areas in the coastal zone.
Transplantation of eelgrass is a proactive approach to restoration
involving the relocation of viable seedlings grown in aquaria, or
mature plants taken from healthy donor beds to the restoration site,
once suitable conditions have been established for eelgrass
survival. This is not a new technique; the earliest recorded transplant
effort involving eelgrass was documented by Addy (1947a, 1947b)
from Massachusetts and several other locations in the mid-Atlantic.
However, in recent years, transplant methods have been refined.
Save The Bay has used a specialized transplant methodology known
as "Transplanting Eelgrass Remotely with Frames" (TERF),
developed by Dr. Fred Short of the University of New Hampshire. The TERF
method involved using clusters of plants temporarily tied with degradable
crepe paper to a weighted frame of wire mesh.
|Attaching eelgrass transplants
Courtesy: Save The Bay
Transplanting is very labor intensive, as it requires divers to
plant the individual units by hand. Often, trained volunteers can
be used to defray the considerable time and labor costs associated
with eelgrass transplant projects. Save The Bay has successfully
used volunteer divers to transplant live plants and in some cases
scatter seeds around transplants.
Eelgrass transplant techniques, along with cost and labor estimates,
are documented by Fonseca et al. (1982a, 1982b, 1982c, 1984, 1985,
1987a, 1987b). Fonseca (1994) reviewed all aspects of seagrass restoration,
including planting guidelines and monitoring programs for the Gulf
of Mexico; however, this information is applicable to seagrass restoration
Descriptions of planting methods, including seeding, stapling,
use of anchored and unanchored sprigs, plugs, peat pots, and transplanting
of individual mature plants are provided by Phillips (1980a), Fonseca
(1994), and Fonseca et al. (1998). Fertilization of transplants
to accelerate growth and bed coalescence is described by Fonseca
et al. (1987, 1998) and Kenworthy and Fonseca (1992). The benefits
of fertilization in eelgrass restoration projects have been inconclusive
Courtesy: University of Rhode Island
Eelgrass can be propagated in estuarine waters by application of
seeds. In Chesapeake Bay, eelgrass seeds have simply been broadcast
by hand off a small motorboat and success rates are documented
by Orth et al. (1994). Researchers in Great South Bay, New York
developed a method of seeding which involved attaching seeds to
a biodegradable tape. The tape is then planted just below the sediment
surface at the desired restoration site (Churchill et al. 1978).
Recently, Steve Granger, a research scientist at University of Rhode Island Graduate School of Oceanography has developed
a boat-pulled sled which deposits seeds below the sediment surface.
His colleague, Mike Traber, has developed a procedure to encase
seeds in a Knox gelatin matrix. This prevents or reduces seed predation
and loss of seeds from waves and currents. Gelatin-encased seeds
are injected into the sediment from the sled using a food processing
pump similar to that which is used to make jelly donuts. A metal
flange mounted on the back of the sled sweeps sediment over the
furrows created by the pump, covering seeds under one inch of sediment.
Test plantings were conducted at two locations in Narragansett Bay
in Fall, 2001. The investigators were able to plant a 400 square meter area
in less than two hours, exceeding initial expectations. Ongoing
research efforts include monitoring the growth of eelgrass in the
newly seeded areas and the evaluation of alternative gelatin agents
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Addy, C.E. 1947a. Germination of eelgrass seed. Journal of
Wildlife Management 11:279.
Addy, C.E. 1947b. Eelgrass planting guide. Maryland Conservationist
Churchill, A.C., A.E. Cok, and M.I. Riner. 1978. Stabilization
of subtidal sediments by the transplantation of the seagrass Zostera
marina L. New York Sea Grant Report, NYSSGR-RS-78-15, Albany, New York.
Cooperative Institute for Coastal and Estuarine Environmental Technology (CICEET).
2002. "Density-dependent effects on grazing and success for seed
generated seagrass (Zostera marina L.) plants." CICEET Progress
Report for the period 08/01/01 through 01/31/02 (http://www.ciceet.unh.edu/spotlight/nixon.html). University
of New Hampshire, Durham, New Hampshire.
Fonseca, M.S., W.J. Kenworthy, and R.C. Phillips. 1982a. A cost-evaluation
technique for restoration of seagrass and other plant communities.
Environmental Conservation 9: 237-41.
Fonseca, M.S., W.J. Kenworthy, and G.W. Thayer. 1982b. A low-cost
planting technique for eelgrass (Zostera marina L.). Coastal
Engineering Technical Aid No. 82-6, U.S. Army Corps of Engineers
Coastal Engineering Research Center, Fort Belvoir, Virginia.
Fonseca, M.S., W.J. Kenworthy, and G.W. Thayer. 1982c. A low-cost
transplanting procedure for sediment stabilization and habitat development
using eelgrass. Wetlands 2:138-51.
Fonseca, M.S., W.J. Kenworthy, K.M. Cheap, C.A. Currin, and G.W.
Thayer. 1984. A low-cost transplanting technique for shoalgrass
(Halodule wrightii) and manatee grass (Syringodium
filiforme). Instruction Report No. EL-84-1, U.S. Army Engineer
Waterways Experiment Station, Vicksburg, Mississippi.
Fonseca, M.S., W.J. Kenworthy, G.W. Thayer, D.Y. Heller, and K.M.
Cheap. 1985. Transplanting of the seagrasses Zostera marina
and Halodule wrightii for sediment stabilization and habitat
development on the east coast of the United States. Technical Report
EL-85-9, U.S. Army Engineer Waterways Experiment Station, Vicksburg,
Fonseca, M.S., W.J. Kenworthy, and G.W. Thayer. 1987a. Transplanting
of the seagrasses Halodule wrightii, Syringodium filiforme,
and Thalassia testudinum for sediment stabilization and
habitat development in the southeast region of the United States.
Technical Report EL-87-8, U.S. Army Engineer Waterways Experiment
Station, Vicksburg, Mississippi.
Fonseca, M.S., W.J. Kenworthy, K. Rittmaster and G.W. Thayer. 1987b.
The use of fertilizer to enhance transplants of the seagrasses Zostera
marina and Halodule wrightii. Technical Report EL-87-12,
U.S. Army Engineer Waterways Experiment Station, Vicksburg, Mississippi.
Fonseca, M.S. 1994. A guide to transplanting seagrasses in the
Gulf of Mexico. Texas A&M University Sea Grant College Program,
TAMU-SG-94-601, College Station, Texas.
Fonseca, M.S., W.J. Kenworthy, and G.W. Thayer. 1998. Guidelines
for the conservation and restoration of seagrasses in the United
States and adjacent waters. NOAA Coastal Ocean Program Decision
Analysis Series No. 12. NOAA Coastal Ocean Office, Silver Spring,
Kenworthy, W.J. and M.S. Fonseca. 1992. The use of fertilizer to
enhance growth of transplanted seagrasses Zostera marina
L. and Halodule wrightii Aschers. Journal of Experimental
Marine Biology and Ecology 163:141-61.
Orth, R.J., M. Luckenbach, and K.A. Moore. 1994. Seed dispersal
in a marine macrophyte: implications for colonization and restoration.
Phillips, R.C. 1980a. Planting guidelines for seagrasses. Coastal
Engineering Technical Aid No. 80-2. U.S. Army Corps of Engineers
Coastal Engineering Research Center, Fort Belvoir, Virginia.
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