Wetlands
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Wetlands. What is a wetland?. There are three characteristics that describe a wetland: Hydrology There must be water at or near the surface of the land for a designated amount of time. Soils Must be hydric or saturated with water to create an anaerobic (oxygen-free environment). Plants

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Wetlands

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Wetlands

Wetlands


What is a wetland

What is a wetland?

  • There are three characteristics that describe a wetland:

  • Hydrology

    • There must be water at or near the surface of the land for a designated amount of time.

  • Soils

    • Must be hydric or saturated with water to create an anaerobic (oxygen-free environment).

  • Plants

    • Must be “wetland plants,” meaning that they require lots of water and the anaerobic conditions that the hydric soil creates. (Smith & Smith, 2001)


Two of the most common wetlands

Two of the most common wetlands

Marshes

  • Wetlands that have lots of herbaceous plants.

  • Also called “wet grasslands”

    Swamps

  • Wetlands that are forested by large trees.


Two components of hydrology

Physical Characteristics

Precipitation, surface and subsurface flow, direction, chemistry, and kinetic energy of the water.

Hydroperiod

Duration, frequency, depth, and flood season

Two components of hydrology


Hydrology

Basin Wetlands (lakes and ponds)

Physical: Water flow is vertical (precipitation)

Hydroperiod: Long with floods during periods of high rainfall.

Hydrology


Hydrology1

Riverine Wetlands (periodically flooded banks of rivers and streams)

Physical: Water flow is both vertical and horizontal (precipitation and stream/river flow)

Hydroperiod: Have short periods of flooding with stream/river flow.

Hydrology


Hydrology2

Fringe Wetlands(along coastal areas of large lakes and oceans)

Physical: Water flow is both vertical and horizontal (precipitation and tidal flow)

Hydroperiod: May be short and regular. Is not seasonal like basin wetlands.

Hydrology


Soils

Soils

  • Soil- a mixture of mineral particles, air, water, bedrock, living and decaying organisms.

  • There are literally thousands of different soils that can serve as great indicators within an ecosystem. Although each type of soil is made of three basic components, (sand, clay, and silt) they can be classified based on the amount of each.


Where do soils come from

Where do soils come from?

  • Soils form as a result of bedrock being broken down into smaller particles.

  • Bedrock is the igneous, metamorphic, and sedimentary rock that is in the lithosphere of the earth (the section of earth closest to the surface).

    • It may take hundreds or thousands of years to form 10cm of soil.

    • Animals, insects, and plant roots can also help break down bedrock and introduce air into soils.

  • Other organic matter, such as dead organisms, also contributes to the soil composition.


  • Three types of soils

    Three types of soils

    • Sandy soils

      • Contain mineral grains ranging from .05-2mm in diameter.

    • Silt soils

      • Soils that have grains ranging from .002-.05mm in diameter.

    • Clay soils

      • Contain mineral grains smaller than .002mm in diameter.


    Soil properties

    Sandy soils

    Has good drainage and aeration

    Does not store water well

    Is not suitable for most plants

    Soil Properties


    Soil properties1

    Silt Soils

    Soils made from minerals

    Granule sizes are between sandy and clay.

    Also known as “rock flour” or “stone dust” when produced by glaciers

    Soil Properties


    Soil properties2

    Clay soils

    Hold water very well

    Do not drain water easily

    Do not have space for air

    Is not suitable for most plants

    Soil Properties


    Soil properties3

    Loam soils

    Soils that contain an equal amount of sand, silt, and clay are called Loam Soils

    The mixture of sand, clay and silt make loam soils an optimal place for plants to grow.

    Are able to hold water and air.

    Soil Properties


    Soil profiles

    Soil profiles are cross-sections of soil that extends from the surface to the bedrock. It is usually broken into layers called “horizons”.

    Horizon O- Topsoil

    Horizon A- Subsoil

    Horizon B- Partially weathered bedrock

    Horizon C- Bedrock

    Soil Profiles


    Wetland plants

    Wetland Plants

    • Plants in wetlands are categorized according to their ability to grow in water or hydric soils.

      • Obligate wetland plants

        • These plants are found in wetlands 99% of the time.

      • Facultative wetland plants

        • Usually live in wetlands (67-99%) but are sometimes found in non-wetlands

      • Facultative plants

        • Are found in wetlands (34-66%) and uplands

      • Facultative upland plants

        • Usually live in non-wetlands (67-99%) but are sometimes found in wetlands

      • Obligate upland plants

        • These plants are found in uplands 99% of the time.


    Native vs exotic

    Native vs. Exotic

    • If a plant is native to a particular area, then it is originally from that area (prior to European settlement).

      • Native plants provide food and habitat for native animals. Without this, the native animals may be forced to migrate to areas.

      • Native plants also keep local genes viable and in the gene pool.


    Native vs exotic1

    Native vs. Exotic

    • Exotic plants were not originally in the area and have been carried to the area in some way.

      • Exotic plants can become invasive where they dominate the ecosystem preventing opportunities for growth for the native plants.

      • Exotic plants also out grow native plants because they have no native predators.

      • Invasive exotic species are the second leading cause of native species extinction (habitat loss being number one).


    Why are wetlands important

    Why are wetlands important?

    • Wetlands serve many roles in our ecosystems. A few of these roles are:

      • Filtering water (removes things like pollutants and sediment)

      • Protect uplands from floods by temporarily storing some of the water

      • Provide sources of food

      • Wildlife habitats

      • Creates healthier watersheds by removing particles from runoff before it reaches the streams.

      • Prevent erosion when on banks of streams, rivers, and lakes


    What happens when wetlands are destroyed

    What happens when wetlands are destroyed?

    • Destruction of wetlands can cause many problems such as:

      • Increased floods

      • Water quality problems

      • Population decrease in plants and animals that live in wetlands


    Can builders destroy wetlands

    Can builders destroy wetlands?

    • Section 401and 404 of the Clean Water Act require developers that are going to destroy a wetland to do three things:

      • Avoid changing wetlands when possible

      • When a wetland is impossible to avoid, they must do as little damage as possible.

      • If a wetland is destroyed, they must rebuild a wetland in another place unless they pay into a special fund to restore streams and wetlands.


    How can wetlands be restored

    How can wetlands be restored?

    • If a section of wetland is destroyed, environmental firms will help rebuild a wetland in another area. The U.S. Army Corps decide how much wetland must be rebuilt based on the quality of wetland that is being destroyed. Once the amount is determined, an environmental company will begin restoration by completing (but is not limited to) the following components:


    How can wetlands be restored continued

    How can wetlands be restored? Continued

    • If developers do not pay into the fund, they must find an area to create a wetland.

      • This area can be a degraded existing wetland or could be an area where a wetland would be appropriate.

    • They will plant vegetation that is appropriate for wetlands.

    • They must make sure that the hydrology is consistent with a wetland by making sure that the system can hold water.

    • If hydric soils are not present, CAE will create a system where they will develop over time.

    • Excavate soil

    • Dig a basin within a flood plain creating an area that can hold water. Water can be retained in an area by creating dams.


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