EMILY WALLISBIOSC 413

SPRING 2011

Salt Marsh Restoration

Basic Salt Marsh Ecology

Salt marshes occur in intertidal zones of moderate to low energy shorelines

Vegetation consists of various halophytic (salt tolerant) grasses, sedges, and rushes that are periodically flooded by estuarine waters

Basic Salt Marsh Ecology

Ecological values: Primary production Nutrient cycling Habitat for fish, birds, and other wildlife Stabilize shorelines High macroinvertebrate diversity

Threats to Salt Marshes

DredgingWaste dischargeHazardous spillsIndirect effects of other activities, such as

damming and agriculture Salinity changes Altered sedimentation rates Nutrient pulses

Natural threats to salt marshes include hurricanes and changes in sea level

Restoration Challenges

Salt marsh habitats are inherently variable in salinity, oxygenation, and velocity of incoming water due to slope

Marshes occur on a wide variety of substrates

Uncertainty of storm free periods that would be conducive to initiating a project

Restoration Challenges

MosquitoesInvasive species, such

as PhragmitesMinimizing human

interference

Salt Marsh Restoration Strategies

Topographical studies Slope of marsh must

ensure adequate influx and efflux of salt water

Reestablishing hydrology Modification of water

control structures to reestablish historical tidal rushing regimes

Salt Marsh Restoration Strategies

Controlling invasive species Phragmites can be

drastically reduced by controlling tidal hydrology

If hydrological manipulation is not feasible or necessary, Phragmites can be controlled with herbicide, burning, or manual removal. These processes usually take several years

Salt Marsh Restoration Strategies

Planting native halophytic vegetation Spartina- cordgrass Salicornia- glassworts Juncus- rushes Cyperus- sedges

Open-water marsh management (OWMM) Using tidal fishes to

control mosquito populations

Why restore salt marshes?

Important areas for faunal biodiversity including fishes, macroinvertebrates, and birds

Salt marshes serve as natural transition zones for oceanic energy, allowing a reduction in water velocity before it reaches land Flood protection

Why restore salt marshes?

Aesthetic appealGlobal averages

estimate a 30% loss in salt marsh habitat (Bostrom et al. 2011)

Crissy Marsh. San Francisco, CA

Works Cited

Athearn ND, Takekawa JY, Shinn JM. “Avian response to early tidal salt marsh restoration at former commercial salt evaporation ponds in San Francisco Bay, California, USA.” Natural Resources and Environmental Issues 15.1 (2009): 77-86. Web. 10 April 2011.

Bostrom C, Pittman S, Simenstad C, Kneib RT. “Seascape ecology of coastal biogenic habitats: advances, gaps, and challenges.” Marine Ecology Progress Series 427 (2011): 191-217. Web. 13 April 2011.

Broome SW, Seneca, ED, Woodhouse WW. “Tidal salt marsh restoration.” Aquatic Botany 32 (1998): 1-22. Web. 10 April 2011.

Johnston RJ, Magnusson G, Mazzotta MJ, Opaluch JJ. “Combining economic and ecological indicators to prioritize salt marsh restoration actions.” American Journal of Agricultural Economics 84:5 (2002): 1362-1370. Web. 10 April 2011.

Rhode Island Habitat Restoration. “Restoration Strategy”. Web. Wolters M, Garbutt A, Bekker RM, Bakker JP, Care PD. “Restoration of salt

marsh vegetation in relation to site suitability, species pool, and dispersal traits.” Journal of Applied Ecology 45 (2008): 904-912. Web. 10 April 2011.