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Biogeochemistry of WetlandsS i d A li tiS i d A li ti
Institute of Food and Agricultural Sciences (IFAS)
Science and ApplicationsScience and Applications
Wetland Biogeochemistry LaboratorySoil and Water Science Department
Wetland Communities
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InstructorMark Clark
Soil and Water Science DepartmentUniversity of Florida
Wetland Community Types Wetland Community Types
Topic Outline
Brief History of Wetlands
Functions and Values
Ecological and Societal Definitions
“Environmental Forcing Functions”
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Hydrarch Succession
Prominent Wetland Community Types
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Learning Objectives
R fl t d b d ti f th li ti f
Wetland Community Types Wetland Community Types
Reflect and broaden perspectives for the application of this course material.
Introduce the concept of “environmental forcing functions”
Introduce the concept of Hydrarch Succession - how forcing functions and community structure can change
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forcing functions and community structure can change over time and space.
Illustrate influence of environmental forcing functions and relate the role of biogeochemical processes.
Historic PerspectiveHistoric Perspective
“Shortly afterwards began the muskegs, which mostly stood under water; these we had to cross forstood under water; these we had to cross for miles; think with what misery, every step up to our knees. The whole of this land of the Lapps was mostly muskeg, hinc vocavi styx. Never can the priest so describe hell, because it is no worse. Never have poets been able to picture styx so fowl. Since that is no fouler
Carl Linnaeus, 1932 (noted taxonomist)
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Historic PerspectiveHistoric Perspective
“[a] horrible desert, the foul damps ascend without ceasing, corrupt the air and render it unfit for respiration… Never was Rum, that cordial of Life, found more necessary than in this Dirty Place”.
Colonel William Byrd III (1674-1744) “Historie of the Dividing Line Betwixt Virginia and North Carolina” in The Westover Manuscripts, written 1728-1736, Petersburg, VA; E. and J. C. Ruffin, printers 1841, 143 pages.
1600’s-18001600’s-1800
http://water.usgs.gov/nwsum/WSP2425/images/fig04.gif
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1800-18601800-1860
http://water.usgs.gov/nwsum/WSP2425/images/fig06.gif
Midwest andTile DrainageMidwest andTile Drainage
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1860-19001860-1900
http://water.usgs.gov/nwsum/WSP2425/images/fig06.gif
1900-19501900-1950
http://water.usgs.gov/nwsum/WSP2425/images/fig06.gif
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1780’s-1980’s1780’s-1980’s
http://water.usgs.gov/nwsum/WSP2425/images/fig06.gif
EXTENT AND LOCATION OF ARTIFICIALLY DRAINED AGRICULTURALLAND IN THE UNITED STATES, 1985
(Courtesy of U.S. Department of Agriculture Economic Research Service.) Frayer et al. estimated that 87 percent of the wetland losses from the mid-1950's to the mid-1970's were due to agricultural conversion.
http://www.npwrc.usgs.gov/resource/othrdata/wetloss/figure5.htm
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Flood ControlFlood Control
Waterfowl, Wildlife and Fisheries Habitat
Waterfowl, Wildlife and Fisheries Habitat
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Water QualityWater Quality
Water SupplyWater Supply
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Non-Game Wildlife Habitat
Non-Game Wildlife Habitat
Vegetative HabitatVegetative Habitat
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Age of EnlightenmentAge of Enlightenment
The miracle of the light pours over the green and brown expanse of sawgrass and of water-shining and slow moving below, the grass and water that is the meaning and central fact of the Everglades of Florida
Marjory Stonemena Douglas, The Everglades: River of Grass
Functions vs. ValuesFunctions vs. ValuesValues
are associated with goods and services that wetlands provide. p
Functionsare natural processes that exist regardless of their perceived value to society.
Societal values of wetlands can change through time, function of wetlands do not change.g
Society does not value all wetland functions, however education, research, and public policy promote the linkages and influence the perceptions of value by society.
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Water QualityWater QualityWater S pplWater S ppl
Wetland Values
Water SupplyWater SupplyHabitatHabitatFood Web ConnectionsFood Web ConnectionsFlood ControlFlood ControlRecreationRecreationEducationEducationArcheologicalArcheological
So What Exactly is a Wetland?So What Exactly is a Wetland?
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"LAND OR AREAS (AS TIDAL FLATS
WETLAND DEFINITIONWETLAND DEFINITION
LAND OR AREAS (AS TIDAL FLATS OR SWAMPS) CONTAINING MUCH SOIL MOISTURE.”
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Source: Webster's collegiate dictionary
WETLAND DEFINITIONWETLAND DEFINITIONWETLAND DEFINITIONWETLAND DEFINITION
"A WETLAND IS RECOGNIZED AS AA WETLAND IS RECOGNIZED AS A SITE WHERE THE WATER-TABLE IS NEAR, AT, OR ABOVE THE SURFACE OF THE GROUND FOR AT LEAST SOME PORTION OF THE YEAR”
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Source: Goodwin and Niering, 1975. Inland wetlands of the U. S., National Park Service
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• "...WETLANDS AS AREAS THAT ARE INUNDATED OR SATURATED BY
WETLAND DEFINITIONWETLAND DEFINITION
INUNDATED OR SATURATED BY SURFACE OR GROUND WATER AT A FREQUENCY AND DURATION SUFFICIENT TO SUPPORT - AND THAT UNDER NORMAL CIRCUMSTANCES DO SUPPORT - A PREVALANCE OF VEGETATION TYPICALLY ADAPTED FOR LIFE IN
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TYPICALLY ADAPTED FOR LIFE IN SATURATED SOIL CONDITIONS”
– Source: President Carter, Executive Order, May 1977, as per U. S. Army Corps of Engineers
• "...A WETLAND IS DESCRIBED AS..LAND WHERE WATER IS THE DOMINANT FACTOR DETERMINING
WETLAND DEFINITIONWETLAND DEFINITION
WATER IS THE DOMINANT FACTOR DETERMINING THE NATURE OF DEVELOPMENT AND THE TYPES OF PLANT AND ANIMAL COMMUNITIES LIVING IN THE SOIL AND ON ITS SURFACE.“
• "... THE SINGLE FEATURE THAT MOST WETLANDS SHARE IS SOIL THAT AT LEAST PERIODICALLY IS
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SHARE IS SOIL THAT, AT LEAST PERIODICALLY,IS SATURATED WITH WATER."
– Source: U. S. Fish and Wildlife. Cowardin et al. 1977: Classification of wetlands and deep wateer habitats of the U. S., p 3.
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A wetland is an ecosystem that depends on constant or recurrent, shallow inundation or saturation at or near the surface of the substrate.
WETLAND DEFINITIONWETLAND DEFINITION
The minimum essential characteristics of a wetland are recurrent, sustained inundation or saturation at or near the surface and the presence of physical, chemical, and biological features reflective of recurrent, sustained inundation or saturation
Common diagnostic features of wetlands are hydric soils
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Common diagnostic features of wetlands are hydric soils and hydrophytic vegetation. These features will be present except where specific physico-chemical, biotic, or anthropogenic factors have removed them or prevented their development.
National Research Council, 1995
I Th M Th O T fI Th M Th O T fIs There More Than One Type of Wetland Community and if so
Why?
Is There More Than One Type of Wetland Community and if so
Why?
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Ecological and Geographical view of Wetlands
Ecological and Geographical view of Wetlands
EcologicallyWetlands have a mix of functions behavingWetlands have a mix of functions behaving both as uplands and as aquatic ecosystems that are often spatially and temporally dynamic.
GeographicallyWetlands form an ecotone (transition or
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(gradient) between upland and aquatic ecosystems.
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Wetland Forcing Functions
Hydrology
wetland community
Hydrology(Hydropattern)
Site Geomorphology Site
Climate
External influence or pre-existing condition
Hydrology-Principal Environmental Forcing Function
Hydrology-Principal Environmental Forcing FunctionDictates oxygen availabilityInfluences biogeochemical cyclesOrganism survival and selectionTemperature regulationTransport of matterIn part determines what kind of wetland develops. Hydrology is made up of several components each of which is influential on community structure and biogeochemical processes.
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HydropatternHydropattern
Duration
Depth FrequencyWetlandCommunity Structure
and Biogeochemical
Function
Timing or
SeasonFlow
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?
Hydrology explains many community difference, but not all
Hydrology explains many community difference, but not all
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Wetland Forcing FunctionsWetland Forcing Functions
HydrologyHydrology(Hydropattern)
Site Geomorphology
Chemical and Physical
Environment
Biota
SiteClimate
Environment
External influence or pre-existing conditionInternal abiotic
Northern PeatlandsNorthern PeatlandsOccur in cool boreal zones with excessive moisturemoistureTypically occur as
Fens (minerotrophic)Bogs (ombrotrophic)Poor fens (transitional)
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0% 100%
Northern Peatlands
HydrologyNorthern Peatlands
Hydrology
67%
33% 67%
33%
Bogs,Pocosins
RiverineFens,
100% 0%
100%67%33%0%
Riverine, Fringe
Seeps
Surface Flow
Northern Peatlands
ChemistryNorthern Peatlands
ChemistryBOGS
FENS
POOR MODERATE-RICH
EXTREME-RICH
• Sphagnum cation exchange system lowers pH in bogs, organic acids resulting from decomposition also lowers pH
RICH RICH
pH 3.0-4.0 4.0-5.5 (5.5) 6.0-6.5 (6.5) 7.0-8.5
Alkalinity 0 0 or low moderate high
Cations (Ca, Na, K, Mg) 0-3 10-20 20-60 70-80
acids resulting from decomposition also lowers pH • Low pH slows decomposition resulting in “raised peatlands” • Productivity of fens is often greater than bogs, but sediment
accretion rates are often lower.– Low acidity in bogs reduces microbial activity– C:N ratio is also high slowing decomposition
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Tidal MarshlandsTidal Marshlands
Tidal Freshwater MarshTidal Freshwater Marsh Tidal Salt MarshTidal Salt Marsh
Riparian Wetlands Nutrient CyclingRiparian Wetlands Nutrient Cycling
Community has “open” nutrient cycles dominatednutrient cycles dominated by adjacent stream or river and runoff from upslope forest.High productivity and cycling of biomassOften act as nutrientOften act as nutrient transformers, assimilating inorganic forms of nutrients and exporting organic forms.
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Salinity
Salinity& Freeze
Spatial and Temporal Scales of Environmental Forcing FunctionsSpatial and Temporal Scales of
Environmental Forcing Functions
Temporal Scale(years)
Spatial Scale (meters2)
<1-3 <100-300 >100-300
Fast(1-10)
Herbaceous vegetation regrowth to steady
state biomass
Non severe fires HydropatternWater quality
Intermediate(10-100)
Residual impact of alligator activity (holes
and nest moundsWoody vegetation
th t t d t t
Sever fires Hurricanes
FreezesDrought/Flood cycle
regrowth to steady-stat biomass
Slow(>100)
Soil Accretion to stable depth
Microbedrock topography
State of Sea levelMacrobedrock
topography
(L. Gunderson, in Davis and Ogden, 1994)
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Wetland Forcing Functions
HydrologyHydrology(Hydropattern)
Chemical and Physical
Environment
Site Geomorphology
Biota
SiteClimate
Environment
External influence or pre-existing conditionInternal abioticInternal biotic
Environmental Forcing Functions and Time
(P. White, in Davis and Ogden, 1994)
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Vegetative/Biogeochemical Change over TimeHydrarch Succession
Vegetative/Biogeochemical Change over TimeHydrarch Succession
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Can Hydrarch Succession Be Reversed?
Can Hydrarch Succession Be Reversed?
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Peat FirePeat Fire
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Putting the Pieces TogetherPutting the Pieces TogetherBiological adaptations provide potential establishment and persistence of species
Establishment - Reproductive strategiesp gPersistence - Morphological (inundation, drought, fire tolerance etc.).
Environmental conditions (Forcing Functions) select among species. Greater the range in forcing functions, the greater the type of communities (as long as genetic diversity is available).diversity is available).
Hydrarch SuccessionChange in community structure over time in response to changes in forcing functions.
Summary of Learning ObjectivesSummary of Learning Objectives
Change in societal value of wetlands has been dramatic over the past 200 years.Wetlands, although aggregated legally as one, are ecologically very diverse.Environmental forcing functions ultimately determine the vegetative character of the community and in many respects its ecological function.Sediment accretion, characteristic of almost all wetlands guarantees the magnitude and influence ofwetlands, guarantees the magnitude and influence of certain forcing functions will change over time.Application of hydrologic and biogeochemical concepts are equally diverse and subject to dynamic change based on differences in biotic and abiotic factors over time and space.
