Welcome to the Salt Marsh

One of the most productive places on

Earth

What is a Salt Marsh?

• Salt marshes are naturally occurring wetlands found within the intertidal zone

• Found along the coast where there is shelter from the incoming high energy waves.

• This intertidal community supports many diverse plants and animals.

Where in the world are they?

A Salt Marsh Has a pattern of Distribution

• There are the highlands or uplands

• The Marsh Border• High Marsh-

accounts for 90% of salt marsh area.

• Pools• Pannes • Channels

Zones of the Salt Marsh

The Uplands• The uplands are forested outcrops of land• Dominated by oak and maple trees.• Understory of shrubs, brushes and vines• They are about 10 feet above sea level• They are rarely flooded by the tide• The soil has more oxygen then salt marsh

The Marsh Border• Where the outer

edge of the upland meets the marsh

• Flooded by extremely high tides

• Dominate plants include: seaside golden rod, switch grass, narrow leaved cattail

The High Marsh• Lies between the low marsh and upland

border• Includes about 90% of the marsh• Very expansive• Soils are saturated with salt water• Plant diversity is low, about 25 species• Dominate plant is Spartina Patens – Salt

marsh hay, spike grass, juncus, asters and sea lavender

Marsh High Lands

Pools and Pannes• Are located within the high marsh• Shallow depressions • Hold standing water• Evaporation yields very high salt levels• Only the most salt tolerant plants and

animals live in the pools or pannes.• Plants include Picklewort, seaside

plantain, spartina alterniflora and blue green algae.

Pools and Pannes

Plants of the Pools and Pannes

The Low Marsh • Located along

seaward edge• Flooded every tide• Occur as a narrow

band along creeks and pools

• Spartina Alterniflora can withstand wet roots

• Reaches a height of six feet!

The Low Marsh and Cord Grass

Functions of the Salt Marsh

• The salt marsh is made of layers and layers of dead grass, bacteria and detritus

• Detritus is tiny pieces of dead grass in the water

• This mix “salt marsh stew” feeds the food chain of the salt marsh

• Detritus is the base of the food chain all the animals in the marsh

Salt Marsh Functions and Values

• Drives food chain• Provides critical

habitat for many important species

• Improves water quality by filtering

• Reduces shoreline erosion

• Maintains elevation of marsh with rising sea level

• Collects and binds sediment

• Cycles nutrients• Primary production

area for many plants and animals

Human Impacts to Salt Marsh

• Direct filling and dredging (50%)

• Tidal restrictions due to roadways (20%)

• Run off and chemical pollution

• Residential growth

Salt Marsh restoration in New Hampshire

1953 Aerial photo vs 1990

Interesting Facts…

• In the 1600s, over 220 million acres of wetlands are thought to have existed in the lower 48 states

• Since then, extensive losses have occurred, and over half of our original wetlands have been drained and converted to other uses.

Major Threats to Salt Marsh Habitat

• Human Actions- Drainage- Dredging and stream channelization- Deposition of fill material- Diking and damming- Tilling for crop production- Levees- Logging- Mining- Construction- Runoff- Air and water pollutants- Changing nutrient levels- Releasing toxic chemicals- Introducing nonnative species- Grazing by domestic animals

• Natural Threats- Erosion- Subsidence- Sea level rise- Droughts- Hurricanes and other storms

Extent of Wetlands Destroyed in Boston

Since 1777