Wetland Science

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Wetland Science
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Wetland scientists examine - biology -
characteristic plants and animals,
microorganisms of different wetland
types - vulnerability to disturbance
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- adaptations to wetland conditions - flooding,
low oxygen levels
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• chemistry
• chemicals characteristic of wetland
• conditions
• - low or no oxygen
• - pH
• - nitrogen and phosphorus
• cycling
• - sulfur cycling
• - iron and manganese
• transformations under
• different oxygen levels

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• geology
• soil formation processes
• geochemistry
• organic matter content
• hydrology water cycle
• sources, chemistry

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Mineral soils Organic soils
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Defining wetlands
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• What features characterize a wetland?
• lowland areas
• might be transitional between terrestrial
• and aquatic habitats
• - can occupy isolated basin
• - covered with shallow, temporary or intermittent
• waters
• water might be present at the surface,
• or within root zone
• soils often rich in organic matter,
• anoxic (no/low oxygen)
• - possess plants adapted to wet conditions

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Diversity of wetland types - makes
defining/describing specific wetlands
difficult - freshwater wetlands - forested
swamps, blackwater and whitewater floodplain
swamps, cypress, hardwood-dominated, bay
swamps, shrub bogs, hydric hammock, fen, -
marshes, bog, depression marsh, marl prairie,
wet prairie, potholes, playa - coastal
wetlands - mangroves, salt marsh (Juncus-or
Spartina-dominated), tidal freshwater
marshes
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For instance, in Florida freshwater 4 main
categories of wetlands - seepage wetlands -
floodplain wetlands - basin wetlands - 15
different types - wet flatlands 4
types marine/estuarine tidal marsh tidal
swamp 21 different types of wetlands defined
by Florida Natural Areas Inventory (FNAI) -
used in wetland delineation, conservation
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Defining Wetlands - definitions/terminology of
different types vary from vaque -gt very
specific - not all wetlands have same
properties - still young, developing field with
much to learn - function/roles -
diversity/habitat regional variation -
natural variation through time - resilience to
disturbance - multidisciplinary approach to
scientific study biology, chemistry,
geology - management/protection requires sound
science
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- value system - land for development
residential, commercial - agricultural,
etc. - natural areas - habitat/biodiversity
protection gt balance not easy to
achieve -wetland restoration works for some
wetlands, not always the best solution
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• many different types, many definitions, some
• confusing (contradictory?)
• older classification - simplistic, didnt
  emphasize
• unique qualities
• laws for regulation, protection
• -gt requires clearer classification
• - scientific input important
• - clarification of different categories
• - management
• - protection

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Features of Wetland 1) water, at surface or
root zone - shallow - depth and duration of
flooding - variable - some continually flooded,
others briefly or with minimal flooding -
water levels can vary within a wetland,
shifting apparent boundaries seasonally or
annually 2) ecotone (transition zone) between
open water and terrestrial systems applies to
many wetlands - margins - share properties of
both - some scientists do not recognize wetland
as distinct ecosystem
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3) defined by specific plant types - animals,
plants and microorganisms vary - some tolerant
of wet and dry conditions, others require wet
conditions - indicator taxa - might not always
be easy to define 4) variable in size - few
acres -gt large tracts 5) range from coastal -gt
inland structure and function vary from wetland
to wetland
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6) human impact varies depending on location -
rural - agricultural impact non-point sources
of nutrients - urban pollution (often point
source) modified watershed hydrology
result of variation-gt one good definition
doesnt exist!
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Why definitions needed? - wetland scientists -
need definition that helps promote wetland
study/differentiation - flexible, but
clear - classification - research -
inventory plants and animals - wetland
managers/regulators - laws/regulations -
need definition with clear language, legally
binding
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• Scientific definitions
• Wetland definitions are lacking from most
• contemporary ecology textbooks
• Limnology texts often include some definition
• ex. Dodson, 2005
• ..characterized by soil saturated with water,
• but with standing water less than 1 m deep,
• often with extensive areas of floating or
  emergent
• vegetation. Wetlands are also called marshes or
• carrs. Swamps have trees standing in water.
• Wetlands can be lentic or lotic.

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• Scientific definitions
• U.S. Fish and Wildlife Service - Circular 39,
  1956
• The term wetlands refers to lowlands covered with
• shallow and sometimes temporary or intermittent
• waters. They are referred to by such names as
• marshes, swamps, bogs, wet meadows, potholes,
• sloughs, and river-overflow lands.
• Shallow lakes and ponds, usually with emergent
• vegetation as a conspicuous feature, are included
  
• in this definition, but the permanent waters of
• streams, reservoirs, and deep lakes are not
• included. Neither are water areas that are so
• temporary as to have little or no effect on the
• development of moist-soil vegetation.
• - early definition, but useful

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• Later definition 1979
• Wetlands are lands transitional between
• terrestrial and aquatic systems where the water
• table is usually at or near the surface or that
• land is covered by shallow water....
• Wetlands must have one or more of the following
• three attributes
• at least periodically, the land supports
• predominantly hydrophytes
• 2) the substrate is predominantly undrained
• hydric soil and
• 3) the substrate is non-soil and is saturated
• with water or covered by shallow water at
• some time during the growing season of each
• year.

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introduced important concepts - hydrophytes -
plants adapted to wet conditions - hydric
soils - soils formed during conditions of
saturation, flooding, or ponding long enough
during the growing season to develop anaerobic
conditions in the upper part. - general,
flexible, comprehensive definition - includes
plants, soils, hydrology - easier for scientists
to use than managers - does promotes
classification, inventory
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• 2) U.S. National Academy of Sciences - 1990s
• National Research Council Committee
• - scientific review of past definitions
• - regional variation
• - scientific ability to analyze wetland
  properties

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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. 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
and hydrophytic vegetation. These features will
be present except where specific physiochemical,
biotic, or anthropogenic factors have removed
them or prevented their development.
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- most comprehensive definition - common
diagnostic features broader, more flexible
than previous definitions
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• 3) International definition
• - International Union for the Conservation of
  Nature
• and Natural Resources 1971
• Ramsar Convention Definition
• Areas of marsh, fen, peatland or water, whether
• natural or artificial, permanent or temporary,
• with water that is static or flowing, fresh,
• brackish, or salt including areas of marine
  water,
• the depth of which at low tide does not exceed
• 6 meters.
• - includes a lot left out by U.S.
• - river and coastal zones
• - depth greater than most definitions
• advantage - included habitat used by migratory
• birds

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Legal definitions - 1970's U.S. Army Corps of
Engineers - Clean Water Act dredge and
fill program U.S. Natural Resources
Conservation Service Swampbuster provision -
Food Security Act -both designed for wetland
protection
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• U.S. Army Corps of Engineers - 1984 definition
• The term wetlands means those areas that are
• inundated or saturated by surface or ground
• water at a frequency and duration sufficient to
• support, and under normal circumstances do
• support, a prevalence of vegetation typically
• adapted for life in saturated soil conditions.
• Wetlands generally include swamps, marshes,
• bogs and similar areas.

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• Controversial - debated in courts
• has had rewording over the years
• - clarify vegetation covered
• Wetlands - considered part of the waters of U.S.
• - since 1975, regulated by U.S. Army Corps of
• Engineers
• - review/regulated dredge-and-fill permits
• - some citizens/companies have bypassed
• permit process by destroying aquatic
• plants
• - included groundwater-supported wetlands

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• 2) Food Security Act Definition - 1995
• wetlands in agricultural areas received
  protection in
• 1985
• The term wetland except when such term is
  part
• of the term converted wetland means land that -
• A) has a predominance of hydric soils
• B) is inundated or saturated by surface or
• groundwater at a frequency and duration
  sufficient
• to support a prevalence of hydrophytic
  vegetation
• typically adapted for life in saturated soil
• conditions and
• C) under normal circumstances does support a
• prevalence of such vegetation.
• For purposes of this Act and any other Act, this
• term shall not include lands in Alaska identified
  as
• having high potential for agricultural
  development
• which have a predominance of permafrost soils.

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• hydric soils - key component
• - excludes Alaska - not science-based, but
• political allows development of wetland
• areas in Alaska

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• Jurisdictional wetlands - legally defined
  wetlands
• in U.S. under the jurisdiction of the Clean Water
  Act
• (Section 404), or the swampbuster provision of
• Food Security Act
• - both definitions emphasize different things
• - Corps - plants determine wetland presence
• -designed for quick use to determine
• jurisdiction
• - FSA - hydric soils
• - excludes non-hydric soils, and Alaska
• many wetlands recognized by scientists may fit
  into
• legal definitions, not all- ex. riparian
  wetlands

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• Goal - delineate wetlands and boundaries
• - ease, quick assessment
• - clear, comprehensive
• - user-friendly
• - standard protocols for identifying wetlands
• plants or soils (wetland delineation)

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Florida Statutes Chapter 62-340, Florida
Administrative Code, Delineation of the Landward
extent of Wetlands and Surface Waters,
subsection 373.019(17)
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Wetlands means those areas that are inundated or
saturated by surface water or ground water at a
frequency and a duration sufficient to support,
and under normal circumstances do support, a
prevalence of vegetation typically adapted for
line in saturated soils. Soils present in
wetlands generally are classified as hydric or
alluvial, or possess characteristics that are
associated with reducing soil conditions. The
prevalent vegetation in wetlands generally
consists of facultative or obligate hydrophytic
Macrophytes that are typically adapted to areas
having soil conditions described above. These
species, due to morphological, physiological, or
reproductive adaptations, have the ability to
grow, reproduce or persist in aquatic
environments or anaerobic soil conditions.
Florida wetlands generally include swamps,
marshes, bayheads, bogs, cypress domes, strands,
sloughs, wet prairies, riverine swamps and
marshes, mangrove swamps and other similar
areas. Florida wetlands generally do not include
longleaf or slash pine flatwoods with an
understory dominated by saw palmetto.
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• one definition - probably not possible nor
  practical
• considering the objectives differ depending on
• user.
• ecological, inventory purposes
• U.S. Fish and Wildlife Service definition most
• accepted
• - regulatory - U.S. Army Corps of Engineers
  definition