Wetland Functions

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Wetland Functions

• The physical, chemical, and biological
  interactions within wetlands are often referred
  to as wetland functions
• Water filtration and purification
• Trapping sediments and contaminants
• Flood control and stream flow regulation
• Erosion reduction
• Habitat for aquatic and terrestrial plants and
  animals

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Water Storage

• Wetlands are reservoirs for rainwater and runoff
• storm abatement (coastal)
• flood mitigation (riparian)
• Moderate stream flows
• Reduce peak water flows
• Maintain flow during low water
• Help prevent flooding by temporarily storing
  water
• Recharge groundwater

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Hydrograph
Sewers with impermeable surface
Sewers, natural surface
Natural surface
Discharge
Lag time
Lag time
Lag time
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Ritchey Woods Natural Area Mitigation Wetland
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Water QualityWater Filtration or Purification

• Remove nutrients, pesticides, metals, and
  bacteria from surface waters where they are
  absorbed, consumed or broken down by plants,
  animals, and chemical processes within the
  wetland
• Wetlands are the earths kidneys
• Limit eutrophication and pollution of water
  bodies

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Particulate Removal

• Filter out sediments and particles suspended in
  runoff water
• Sediments typically contain adsorbed nutrients
  and metals
• Limits siltation
• Reduces Habitat Impacts

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Nutrient Cycling

• Complex biogeochemical cycles occur in wetlands
  (C, N, P, S)
• Wetlands are great chemical transformers
• Enhance the decomposition of organic matter,
  incorporating nutrients back into the food chain

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Function of Wetland Soils

• Transformation of various elements in hydric
  soils
• Denitrification NO3- ? N2
• Converts sulfates (SO4-2) into sulfides (H2S) and
  insoluble complexes with phosphate and metal ions
  removes sulfates caused by anthropogenic
  activities
• Sequesters C decomposition of organic material

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Geologic Function of Wetlands

• Anaerobic conditions ? exceptional preservation
  qualities
• Store pollen, fossils, and human artifacts
• Animals from the last Ice Age were discovered in
  bogs.
• Used to reconstruct paleoclimates, animal
  evolution, and vegetation type

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Function of Wetland Biota

• Plants reduce the erosive potential of peak flows
  ? stabilize shorelines and levees
• Produce an abundance of detritus ?consumption by
  commercially important vertebrates and
  invertebrates.

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Plant and Animal Communities

• Wetlands in the United States support
• about 5,000 plant species
• 190 species of amphibians
• 80 of Americas bird population
• Provide critical habitat

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Wetland Biota

• Large volume of biomass commercially important
  plants and animals
• 95 of the harvested fish and shellfish species
  are wetland dependent
• Wetland timber about 22 million ha

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Wetland Biota

• Wetlands occupy 3.5 of the land area ? large
  amount of habitat yet a small amount of habitat
• Estimated that 50 of the 209 animals listed that
  are federally listed threatened or endangered
  species occur in wetlands
• More than 50 of the 800 species of protected
  migratory bird populations rely on wetlands

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Wetland Values
The characteristics of wetlands that are
beneficial to society are called wetland values
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• valuation can be a subjective assessment,
  particularly the valuation of indirect use, or
  future use
• The ecological diversity and high productivity of
  wetlands make them one of the most scenic
  features on any landscape.

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