Transcript Wetlands - Woodland Hills School District

Wetlands
PA State Standard for Environment &
Ecology
4.1.10.D & E
Wetlands:
• An area that contains unique types of soil
• Home to plants adapted to the wet
environment
• Contains water all year or at certain times
of the year.
Common names for wetlands
A. Bog
B. Swamps
C. Marshes
A
C
B
Bog
• A wetland in which soils
consist of decomposed
plant material.
(peat/muck)
• Dominant plants are the
mosses
– Other plants include:
shrubs, evergreens,
water lilies,
cranberries, and
blueberries
Bog
• Very acidic (low pH),
little O2 due the very
little movement of
water in or out.
• Abundance of frogs,
turtles, insects, some
birds (usually no fish)
Swamp
• Forested wetland
• Dominated by trees
& brushes
• Soil drains slowly;
rich in nutrients
• Classified depending
on dominant tree type
– Conifer Swamps
ex: cedar, pines…
– Hardwood Swamps
ex. Maples,
willows…
• Deer, raccoons,
herons, egrets,
woodpeckers,
snakes,frogs, turtles
• Few fish
Swamp
Marshes
• Forms at the mouth of
a river or in areas
where there’s poor
drainage
• Rich in nutrients
• Dominated by
grasses, sedges,
bulrushes, cattails
• Beavers, frogs, turtles,
raccoons, muskrats,
birds, insects
PA wetlands; Chapter 105 of
Commonwealth of PA code
• “Those areas that are inundated or
saturated by surface or groundwater at a
frequency and duration sufficient to
support, and that under normal
circumstances do support, a prevalence of
vegetation typically adapted for life in
saturated soil conditions…”
• Are protected by the law.
There are 29 million acres of land area in PA.
• 407,000 acres are classified as wetlands.
Bonus
What percentage is that of the whole?
407,000/29,000,000
*100 = ? %
• Over 4,000 have been restored since 1990.
1.4%
PA’s classification of wetlands
1. Forested:
• Mature woody trees over 20 feet tall.
•
Most abundant wetland in PA
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220,000 acres
Red & silver maples, green ash, black gums,
river birches
Bonus - What percentage is that of the whole?
220,000/407,000 *100= ?
54%
PA’s classification of wetlands
2. Scrub/shrub:
• Trees less than 20 ft tall,
• 2nd most abundant wetland in PA.
• Alders, willows
• 139,000 acres
Bonus - What percentage is that of the
whole?
34%
PA’s classification of wetlands
3. Emergent:
• Marshy areas plants rooted in soil but
emerge above water
- 52,000 acres
– Rushes, grasses, sedges
Bonus - What percentage is that of the whole?
13%
Importance of Wetlands.
• In the past, wetlands were mostly
considered to be wastelands. As the
United States was settled and people
moved west, swamps and marshes were
obstructions along the way.
• Many were drained to be replaced by
farmland, railroads and road construction.
Importance of Wetlands.
• In recent decades many people have come
to recognize the values of wetlands.
• No longer the forgotten stepchild of our
environment, some scientists call them
natures kidneys because of the natural
cleansing functions they perform.
Importance of Wetlands.
• They provide rich habitat for a diverse
range of plant and animal species
• Protection from flooding and erosion.
• Are also important to the nutrient cycle.
Functions of wetlands
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Habitat
Food factories
Spawning grounds & nurseries
Cycling of nutrients
Buffer zones
Pollution control
Habitat
• Home to bacteria, protists, plants and animals,
including many threatened and endangered
species
• 35% of threatened and endangered species of the
US
• 500 of PA’s concerned plants
• 80% of PA’s amphibians
• 25% of all PA‘s reptiles
• >120 species of birds
Food factories
• High productivity rates due to large amount of
plants
Food factories
• High productivity rates due to large amount of
plants
• Food sources
– Plants above the water
– Decomposing plants below the water
– These organisms that eat the plants provide
food for all of the other organisms in the chain
Spawning grounds and nurseries
• Amphibians, ducks, geese, swans, bitterns,
and herons reproduce in wetlands
• Large fish like walleye and bluegills that
live in open water spawn in shallow water
wetlands
Cycling nutrients
• Plants drive this ecosystem through
photosynthesis
• Use CO2 and solar energy and convert it
into O2 and food.
• Autotrophs & Heterotrophs
Buffer Zones
• Act as “natural sponges” to absorb excess
runoff and slowly release it back into the
environment
• Store and slow water
– Reduces flooding, runoff, and erosion
Pollution Control
• Sediment is the primary water pollutant in
PA
– By slowing water flow, it reduces sediment by
allowing it to settle out of the water.
• Prevent air pollution
– Plants store carbon rather than releasing it into
the air
Loss of open space due to
development causes negative effects
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Reduce recreational areas
Less attractive to business
Reduce air and water quality
Increase flooding due to less vegetation
and more concrete
Benefits of preserving wetlands
• Improves air and water quality. Wetland
plants improve air quality by removing
harmful gases and contributing oxygen.
They improve water quality by filtering out
harmful substances from the water.
• Provide habitat for wildlife
• Lessen the chances and effects of flooding
Urban wetlands as a type of
open space.
• May be the remnants of streams and rivers left
after development
• Sometimes they result from planned or poorly
planned development
– Ex: drainage ditches and retention ponds.
• Provide the following services:
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Habitats for plants and animals
Buffer runoff
Trap and filter pollutants like iron and lead
Treat wastewater
Wetlands vs. Development
No net loss.
• Regulation for
development that
stopped the loss of
wetland acreage.
• If a wetland is
destroyed, a new one
needs to be made to
compensate.
Net gain
• The idea of restoring
damaged wetlands
and establishing new
wetlands.
Factors that affect wetlands and
watersheds
• The major factor affecting US wetlands are
human activities:
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Agriculture
Urbanization & construction
Mining
Industry
Waste disposal
Effects of Agriculture
Agricultural practices can disrupt or even destroy a
wetland in different ways.
– When food/resources are harvested.
– Building drainage and irrigation ditches that
divert water away.
– Build-up of pesticides, fertilizers, nutrients,
pathogens, and salts in wetland soils due to
runoff.
– Runoff of livestock waste and soil from
erosion.
Urbanization and construction
• Runoff carries many pollutants (sediments,
wastes, pesticides, salts, heavy metals)
from urban areas and construction sites.
• Changing the natural flow of water
decreasing the buffering ability of the
wetland because it diverts the water away.
Mining
Especially important in PA.
• Acid drainage from both active and
abandoned mines lowers the pH of
wetlands which causes heavy metals to
precipitate out.
• Wetlands can filter out some of the
pollutants but has limits.
Industry
• New construction of office buildings,
factories, and processing plants reduce
wetland acreage
• Both water intake and release of too much
water can cause habitat loss or biodiversity
loss. (ex. thermal pollution leads to algae
blooms)
Waste disposal
Another by-product of urbanization.
• Solid waste at landfills leaking into wetlands.
(most landfills are within a mile or less of
wetlands)
• Sludge and wastewater treatment effluent are
sometime introduced to waterways and wetlands.
• They are rich in nitrogen and phosphorus which
leads to algal blooms.
PA’s Stream ReLeaf Program
• A program launched in 1997 with several
objectives:
– Restore streamside buffers on private and
public land.
– Conserving streamside buffers to protect and
improve forest diversity.
– Educate the public about the importance of
wetlands.
– Develop activities to raise awareness of
wetlands.
Natural Events that affect Wetlands.
• Floods can have both a positive and negative
effect on a wetland.
• Erosion and sediment deposition can change the
physical conditions of a wetland.
• Drought reduces the volume of water in a
wetland.
• Fires can have positive and negative effects.
• Global Climate Change – changes in climate
affect the abundance of water. (too cold –
decrease/too warm – increase)