Watersheds & Wetlands

Wetlands Pennsylvania Wetlands Wetlands at Work Suburban Swamps

Chapter 1

Lesson 1.4

PA Academic Standards for Environment & Ecology 4.1.10D

Describe the multiple functions of wetlands.

Lesson Objectives:• Students will analyze wetlands in terms of the type of soil

and vegetation present in terms of their hydrology.• Students will describe some of the functions of wetlands

and explain how a wetland influences water quality, wildlife, and water retention.

Wetlands• Definition: an area that contains unique types of

soil, is home to plants adapted to a wet environment, and contains water all year or at certain times during the year

Wetland DelineationDetermined by 3 parameters:

• Hydrology

• Soils

• Vegetation

1.Hydrology: must have standing water for 3 weeks during the growing season

It is the weakest of the 3 parameters….meaning hardest to clarify

2. Soils

• Take a soil sample and look for a mottled soil….contrasting colors

OR… a gleyed soil-develops when anaerobic conditions produce a reduction of iron or manganese….gray soil color

3. Vegetation• Look on National wetlands inventory list

a. Obligate - occurs almost always in wetland - 99%

b. Facultative wetland - usually occur in wetland

67%-99%

c. Facultative - Equally likely to occur in wetlands

and nonwetlandsd. Facultative upland - usually occur in non-wetland;

occasionally in wetlands

e. Obligate upland - most of the time in nonwetland

> 99% See handouts

• Wetlands are often called many different names, each with a slightly different composition.

• Main types of wetlands include: Bogs

Swamps

Marshes

Bog• Definition: wetland in which soils consist

predominantly of decomposed plant material called peat or muck.

• Mosses are the dominant plants. • Other vegetation includes shrubs, some species of evergreens, water lilies, pitcher plants, cranberries, and blueberries.• Bogs tend to be very acidic and contain little oxygen, since the water in the bog moves very little.• Common organisms include frogs, turtles, insects, and certain birds.

BOG

Swamp• Definition: forested wetland in which trees and

bushes are the dominant plants

• The dominant plants are trees and bushes.• Swamps are classified according to the dominant tree in the wetland.• There are two main types of swamps.

Conifer swamps Hardwood swamps

• Common organisms include white-tailed deer, raccoons, herons, egrets, woodpeckers, snakes, frogs, and turtles.

• Coniferous swamps are dominated by cedars, pines, spruces, and hemlock trees.

• Hardwood swamps are dominated by maples, willow, aspen, birch, elm, and oak trees.

Marsh• Definition: wetland that generally forms at the

mouth of a river or in areas where there is poor drainage

• Marsh soils are richer in nutrients and support vegetation such as grasses, sedges, bulrushes, cattails. • Common organisms include beavers, frogs, turtles, raccoons, muskrats, opossums, birds, and insects.

Marsh

Pennsylvania Wetlands

• Pennsylvania wetlands cover 407,000 acres of the total 29,000,000 acres of land.

Almost 4,000 acres of additional wetlands have been restored since 1990.

• There are three general types of wetlands recognized in Pennsylvania

Forested wetlands

Scrub-shrub wetlands

Emergent wetlands

Chapter 105 of the Commonwealth of Pennsylvania code defines a wetland as … “ Those areas that are inundated or saturated by surface or groundwater at a frequency and duration sufficient to support a prevalence of vegetation typically adapted for life in saturated soil conditions … “

Forested Wetlands• Definition: areas where the dominant plant types include

mature woody trees• 220,000 acres (45%) of Pennsylvania wetlands are of this type

Examples: Red Maple Silver Maple River BirchBlack Gum Green Ash

Scrub-shrub Wetlands• Definition: wetlands whose dominant plants are scrub

and shrubs as well as trees that are less than 20 feet tall, such as alders and willows

• Dominated by shrubs, small trees, and low-lying vegetation.

• 139,000 acres (28%) of Pennsylvania wetlands are of this type.

Examples: Spice Bush, Swamp Honeysuckle, High-bush blueberry

Emergent Wetlands• Definition: marshy areas where plants are rooted in soil

but emerge above water

• Dominated by rushes, grasses, and sedges.• 52,000 acres (14%) of Pennsylvania wetlands are of this

type.

Examples: Sedges, Rushes, Wild Rice, Cattails

Wetlands at Work

• Wetland have many roles. Wetlands provide …

Habitat Food Spawning grounds and nurseries Cycling of nutrients Buffer zones Pollution control

Habitat

• Wetlands are home to a variety of species. These include bacteria, protists, plants, and animals.

• Wetlands are home to many threatened or endangered species.

• Wetland are home to nearly 35% of all threatened and endangered species in the United States.

Wetland Habitat

Food• Wetlands are considered “food factories” because

they have very high primary productivity rates.

• Plants, the base of all food chains, are the primary organisms responsible for this high productivity rate.

• Decomposing plants can also provide food for other organisms (like bacteria), which then provide food to wetland vertebrates.

Spawning grounds and Nurseries

• Wetlands are ideal places for many organisms to lay eggs, care for their young, and provide safer habitats for some juveniles species.

• Some organisms leave rivers and enter floodplains, some organisms enter coastal wetlands, and some organisms leave open water lakes to spawn in shallower waters of nearby wetlands.

Cycling Nutrients

• Wetlands cycle nutrients such as phosphorous, nitrogen, oxygen, and carbon dioxide through an ecosystem.

• Plants, via photosynthesis, play an active role in cycling these elements through the system.

Nitrogen Cycle

Carbon-Oxygen Cycle

Buffer Zones

• Wetlands are important buffer zones because they function as “natural sponges”.

• Wetlands have the capacity to absorb excess runoff, store water, prevent flooding by retaining large amounts of water in its soils, and protect coastal regions.

Buffer Zones

• Pennsylvania agriculture also benefits from these wetland characteristics.

• Wetlands reduce the likelihood of flood damage to crops due to excess runoff in developing regions.

• Wetlands also remove contaminants from upstream waters, preventing such runoff from mixing with sediments washed onto the floodplain.

Without a vegetative buffer

With a vegetative buffer

Pollution Control

• Wetlands play a vital role in removing unwanted contaminants from waterways.

• Pennsylvania’s major pollutant (by volume) is sediment.

• Wetlands function to slow the velocity of the water, allowing particles suspending in the water to settle, improving the quality of water downstream.

Suburban Wetlands• Urbanization has disrupted and destroyed

many wetlands directly associated with nearby waterways.

• The preservation of “open spaces” includes the preservation of urban wetlands, which include historic wetlands, as well as wetlands that resulted from poorly planned and engineered development.

• Suburban wetlands provide the same important functions as do “typical” wetlands.

• Suburban wetlands buffer runoff from increased amounts of pavement and other impervious surfaces.

• Suburban wetlands aid in treating large volumes of wastewater produced by cities and towns.

A huge suburban wetland project is being planned to improve the quality of Shanghai's tap water

Lesson 1.4

• bog• emergent wetlands• forested wetlands• heterotrophs• marsh

• scrub-shrub wetlands• swamp

• wetland