Transcript 4. North Atlantic Coastal Marshes

North Atlantic Coastal Marshes
Marshes Defined
 Marshes
Defined: Wetlands frequently or
continually covered with water,
characterized by emergent soft vegetation
adapted to saturated soil conditions
 There are many types of marshes:
Prairie Potholes to Everglades
Coastal to Inland
Saltwater to Freshwater
Marshes Defined
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Freshwater, Brackish, or Saline
Coastal marshes are most prevalent in the United
States on the eastern coast from Maine to Florida
and continuing on to Louisiana and Texas along the
Gulf of Mexico
Two types of coastal marshes:
Saline tidal marshes which are covered and
exposed daily by the tide
Saline marsh is covered by water sporadically
Marsh Ingredients
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A transect of a 'typical' coastal marsh could
include seawater, short salt marsh grasses, taller
salt marsh grasses and other plants, brackish
water plants on slight elevation, and taller
brackish water plants on land above high tide.
This biome includes plants which thrive on salty
or brackish water, and many animals which
inhabit this rich environment.
All marshes are influenced by the
ocean tides
These pictures are taken of the same place within the same day
Low Tide
High Tide
Functions and Values
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Buffer stormy seas, slow shoreline erosion, and
absorb excess nutrients
 The winding channels along with dense
vegetation can absorb flood waters and release
them slowly
 The gradual release of water reduces erosion
and possible property damage.
 Coastal wetlands absorb the erosive energy of
waves, further reducing erosion.
Functions and Values
 Trap
potential pollutants before they reach
important waterways
 Pollutants are carried by sediment
particles into the marsh and settle into the
marsh which limits the impact on humans
 Marsh plants can absorb excess nutrients,
reducing algal blooms in coastal bays
Functions and Values
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Provide vital food and habitat for clams, crabs,
juvenile fish, and offer shelter and nesting sites
for many species of waterfowl and for numerous
recreational and commercial species
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Gulf of Maine Coastal Program identified
approximately 300 nationally significant nesting
islands and is working in partnerships to
promote habitat protection and restoration
Casco Bay
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Casco Bay, located where New England's
rockbound coast meets southern beaches and
salt marshes, is surrounded by 15 towns. Gulf of
Maine Coastal Program identified and mapped
important habitat for 9 groups of species,
including waterbirds, seabirds, wading birds,
fish, eelgrass, cordgrass, marine worms,
shellfish and endangered/threatened species.
Results are being used to catalyze voluntary
habitat protection efforts in the region
Productivity
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Marshes are considered one of the most productive
ecosystems on earth
 Productivity is usually defined as the amount of
biomass,or living tissue, that an ecosystem produces
over a period of time.
 A large amount of detritus is produced which refers to
dead organic material
 Plant diversity, biochemical
reactions, and hydrology of these
habitats make them extremely
productive.
Plants
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Marshes support a
highly specialized set
of life that is adapted
for the saline
conditions and
changing water levels
 Communities are
composed of 90%
grasses and grass
like plants, 5% woody
plants, and 5% forbs
Fish Nursery and Uses
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Plenty of Food-Young fish often have a varied diet,
foraging for food on the marsh bottom on plants or
organisms. Organic detritus is another food source
along with algae
Plenty of Cover- Small fish can hide from predators
because the shallow brackish water excludes larger fish
A number of migratory fish must travel back and forth
between salt and freshwater to complete their life cycle.
Marshes provide pathways that link fresh and salt water
and provide an area to feed and prepare for migration
Animals
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Tidal wetlands are the wintering homes for great flocks of
migratory waterfowl. Other wildlife, including muskrats,
beaver, otter, song birds and wading birds, rely on
wetlands for food and cover. Fish and shellfish, many of
which are commercially valuable, use wetlands as
spawning or nursery areas. Thousands of aquatic
animals, including reptiles amphibians, worms, insects,
snails, mussels and tiny crustaceans, thrive in wetlands
and are food for other organisms.
Animals
Fiddler Crabs
Painted Box Turtles
Ribbed Mussels
Animals
 Aquatic
insects also thrive in marshes
 Some insects found include:
 Giant Water Bug, also known as the Toebiter
 Brown Water Scorpion
 Mosquitoes
 Dragonflies
 Damselflies
Bird Use
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This abundance of
insects, amphibians and
plants is like a meal
waiting to happen for
birds, which is one
reason why birds are so
populous in marshes.
Non-Migrating Birds
 Herons,
Rails, and Bitterns
Human Use
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Human industries such as seafood and tourism are
dependent upon healthy coastal marshes both for their
ability to produce and sustain life and for their ability to
transform human pollution to less toxic materials.
Economically, wetlands provide opportunities for fishing,
crabbing and hunting. In the Gulf of Maine, estuaries and
coastal wetlands are used by two-thirds of commercially
valuable fish, shellfish,baitworms,and other forage
organisms for at least some point in their life
Other popular activities include hiking, bird watching,
photography and wildlife study. People are lured by the
beauty of wetlands and much leisure time is spent simply
enjoying the sights and sounds these areas can offer.
Loss of Marshes
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reason for early loss is dredging,
filling, and draining
 More recent loss is due to pollution, rise in
sea level, and structures that block tidal
flows
Degradation
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Marshes have been drained all along the east coast in hopes to
eradicate mosquitos
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Used as dumps, over-hunted, and many other abuses
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Filled to help provide habitable land for the high concentrations of
people
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Coastal marshes are also very proximate to most east coast tourist
beaches, stretching from Maine to Florida. As a result, they have
been filled or otherwise constricted as development expanded
tourist communities.
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Other human-induced factors, such as air and water pollution, global
warming, and rising sea levels have also afflicted coastal marshes.
Effects of direct and indirect human encroachments have resulted in
the obliteration of many marshes, and the declining health of many
others.
Exotic Species
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Nutria are semi-aquatic rodents native to South America,
which now also occupy brackish water marshes in parts
of Maryland, Virginia and Delaware.
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The Problem
Nutria's foraging of wetland root mats results in:
The loss of wetlands' filtering capacity
Rapid erosion of marshes
Loss of habitat for native species due to wetland loss
Competitive pressure on native muskrat species
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Exotics Continued
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Water chestnut – Trapa natans – an invasive plant that can blanket the
surface of ponds. Water chestnut creates a monoculture, preventing
sunlight from reaching SAV and creating large, spiny seed pods that
interfere with recreational use of waterways and beaches.
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Purple loosestrife – Lythrum salicaria – a pretty but persistently invasive
plant. Like water chestnut, loosestrife creates a monoculture of plants in
freshwater wetlands, excluding use of habitat by a diversity of native plants.
It appears to have minimal value to native species.
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DNR also lists five nuisance species that have not yet caused known
problems but which may have the potential to be harmful are:
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Zebra mussel – Dreissena polymorpha
Grass carp – Ctenopharyngodon idella
Japanese shore crab – Hemigrapsus sanguineus
Rapa whelk – Rapana venosa
Nuclear worm – Namalycastis abiuma
Suminoe oyster – Crassostrea ariakensis
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Overcrowding
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Rising population size
of Snow Geese
Large goose eat outs
Increased salinity
levels
Increased tidal energy
flow
Impossible conditions
for vegetation to be
replaced
Conservation
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Some restoration activities include constructing
passages to allow fish to swim upstream or out to sea,
replacing culverts to bring back natural tidal flow and
removing dams to restore vast stretches of a watershed
Restoration projects may involve replacement of native
plants and grasses or rerouting or redesigning roads and
bridges. Ensuring and protecting the safety of these
valuable salt marsh ecosystems and the organisms
found within, plays an important role in protecting all
aquatic and coastal habitats and ecosystems
Conservation
•The Clean Water Act(1972) Section
404 established the process by which
developers had to get permits to
change wetlands through dredging or
filling
•Coastal Zone Management
Act(1972) established the Office of
Coastal Zone Management
•Ducks Unlimited and The Nature
Conservacy
Conclusion
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Marshes provide
vital habitats for
many species of
animals and plants
 They provide buffer
zones from oceans
 They help filter out
nutrients and
pollutants
Conclusion Continued
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Marshes connect aquatic ecosystems to
terrestrial ecosystems
 Then maintain an intricate balance that helps
sustain many species of wildlife as well as
protect humans from our own mistakes
 Without this ecosystem, results would not only
be negative in regards to the species found
there, it would interrupt our way of life in ways
we can’t imagine