WetlandsWetlands

PA State Standard for Environment & PA State Standard for Environment & EcologyEcology

4.1.10.D & E4.1.10.D & E

Wetlands:Wetlands:

• An area that contains unique types of soilAn area that contains unique types of soil

• Home to plants adapted to the wet Home to plants adapted to the wet environment environment

• Contains water all year or at certain times Contains water all year or at certain times of the year. of the year.

Common names for wetlands

A. Bog B. Swamps C. Marshes

C

B

A

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

Swamp• 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

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?

• Over 4,000 have been restored since 1990.

407,000/29,000,000 *100 = ? %

1.4%

PA’s classification of wetlands

1. Forested:

• Mature woody trees over 20 feet tall.

• Most abundant wetland in PA– 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

• 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

• 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:– Habitats for plants and animals– Buffer runoff– Trap and filter pollutants like iron and lead– Treat wastewater

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.

Wetlands vs. Development

Factors that affect wetlands and watersheds

• The major factor affecting US wetlands are human activities:– 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)