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Wetland Distribution

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Global wetland distribution

Based on: vegetation, inundation, function

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Inundated area distribution

DISCover Wetland distribution

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Geomorphology

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UP Wetland Landscape

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Vegetation, Hydrology, Vegetation, Hydrology, LandformsLandforms

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Vegetation, Wildlife Habitat

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Wetlands: DefinitionThe term "wetlands" means those areas that are inundated or saturatedby surface or ground water at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typicallyprevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs, and similar areas.

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Wetlands Criteria

1 Hydrology saturated soils for part of1. Hydrology – saturated soils for part of year; (isolated vs. “navigable”, nexus)

2. Vegetation - prevalence of vegetation typically adapted for life in saturated soil

3. Soils – “hydric”S y

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Hydrophytic Vegetation

Plant Indicator Status Categories:Plant Indicator Status Categories:1. OBLIGATE WETLAND PLANTS (OBL): almost always

(>99%) occur in wetlands;2. FACULTATIVE WETLAND PLANTS (FACW): usually (67-

99%) occur in wetlands;3. FACULTATIVE PLANTS (FAC): equally likely to occur in

wetlands or non-wetlands (probability 34-66%);wetlands or non wetlands (probability 34 66%);4. FACULTATIVE UPLAND PLANTS (FACU): usually occur in

non-wetlands but occasionally are found in wetlands (1-33%);5. OBLIGATE UPLAND PLANTS (UPL): almost always (>99%)

occur in non-wetlands;

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HYDROPHYTIC VEGETATION

Hydrophytic plants include OBL, FACW(+/-), FAC+, h d h i l i l dFAC; non-hydrophytic plants include FAC-, UPL

A predominance of wetland vegetation occurs, and the wetland vegetation criterion is satisfied when more than 50 percent of thesatisfied, when more than 50 percent of the dominant plant species (>20% cover) present have a wetland indicator status of OBL, FACW+, FACW, FACW-. FAC+ or FAC.

Hydric soils: soils that are saturated, ponded, or flooded long enough (> 2 weeks) during the growing season to develop anaerobic conditions

Common indicators of hydric soils:

in the upper part.

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• organic matter content;• colored layers (Fe, sulfide, OM, gleyed);• gley soils;• H2S;

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Wetland classification

Types of Wetlands

Classification schemes:1 Hydrology: coastal/estuarine ground-water fed1. Hydrology: coastal/estuarine, ground water fed,

perched, riparian, vernal;2. Vegetation: (1) Submerged (Pond), Emergent

(Marsh), Shrub, Forested (Swamp); (2) alder thickets, (reed-) sedge meadows (wet meadows), spruce bogs, cypress swamps, cedar swamps, hardwood swamps, Floodplain forest

3. Nutrient source: minerotrophic (rich and poor fens) vs. ombrotrophic (bogs)

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RiparianWet meadow, sedge meadowMinerotrophic

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Coastal, barrier beachEmergent, marshMinerotrophic

Groundwater-fed, minerotrophic, fenSedge meadow, wet meadow, emergent

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CoastalPond, MarshEmergent, submergedMinerotrophic

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Why do we care about Wetlands?

• ?• ?• ?• ?• ?• ?

Why do we care about Wetlands?

• Wonders;• Loss of wetlands; • Functions of wetlands;• Monetary benefits of wetlands and their

functions;• “Constructed wetlands” (mitigation,

treatment);

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LOSS

GAIN

Functions of Wetlands

Why are wetlands important?

Functions of Wetlands

1. Water storage (flood mitigation – 1 acre can store 1-1.5x106

gallons);2. Water filtration (removal of nutrients, suspended solids);3. Habitat (e.g., Up to 50% of NA bird species nest or feed in

wetlands; wetlands occupy 5% of land surface in U.S. but arewetlands; wetlands occupy 5% of land surface in U.S. but are home to 31% of plant species);

4. Global and local element cycles;

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Water storage

Energy source not just locally

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Wildlife habitat, food source

Earth surface composition

• 75% oceans;25% i l• 25% terrestrial;

• ~1% wetland, 0.6% lakes & reservoirs;

Surface area

lakes

peatlands

reservoirs

oceans

terrestrial

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Oceanbasins

Oceanmargins

Lakes

L. Superior

Reservoirs

Peatlands

http://www.epa.gov/methane/

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Human impacts on wetlands• Draining - >50% of U.S. wetlands drained;

– Agricultureg– Coastlines – residential, recreational– River corridors – flood protection, levees, agric.

• Acid rain;– Acidification;– Decreased CH4 emissions;– Fertilization with N, enhanced N2O emissions;

Increased Hg deposition and methylation;– Increased Hg deposition and methylation;• Climate change – decreased DOC export, gas emissions,

permafrost thawing, forest fires• Oil & gas extraction – Alaska ANWR

Values of Wetlands

Cost-Benefit Analysis

1. 1991 wetland-related ecotourism added $59 BILLION to U.S. economy (U.S. GDP in 2005 was $12,456 BILLION);

2. ~71% of $111-billion fishing industry depends on wetland species;

3. In IL, 80% of flood damage occurred to construction on “converted” wetlands;

4. In MA, USACE estimated that wetland destruction would result in $17 million annual flood damage;

Unquantifiable values:1. Value of global carbon storage in wetlands?2. Value of trace gas emissions and uptake by wetlands?

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Wetlands: Regulations1. Section 303 Clean Water Act: Requires water quality criteria for

“all” U.S. surface waters including wetlands;2. Section 402 Clean Water Act: Requires permits (NPDES) for

di h i t f tdischarges into surface waters;3. Section 404 Clean Water Act: Permit required for discharge of

dredge or fill material into U.S. waters;

Permits (CWA sec. 404) are issued by U.S. Army Corps of Engineers. EPA comments on federal permit applications. EPA may veto Corp permit decisions and take action againstmay veto Corp permit decisions and take action against violators. EPA offers support to state wetland programs.

A major weakness in current legal definitions is that small wetlands not adjacent to or not contiguous with navigable waterways (i.e., isolated wetlands) are not specifically protected by federal statutes.

Are Wetlands Legally Protected?

• CWA – offers protection for “U S waters” thatCWA offers protection for U.S. waters that, by inference, are equated with “navigable waters”;

• Until 2006, EPA and ACE interpreted statute broadly to include most all wetlands;

• Rapanos vs. U.S. – case decided by U.S. Supreme Court in 2006 includes wetlands only if they have

“ i ifi ” i h i bla “significant nexus” with a navigable water;• States may still protect wetlands independently of

federal government;

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How significant is the Rapanos decision?

• It is unknown how ACE and EPA will define “significant t s u ow ow C a d w de e s g ca tnexus” nor how their definitions will stand up in court;

• It is not known what fraction of existing wetlands lack surface water connections with “navigable waters”;– USFWS studied 72 “sites” across the U.S. that covered most types

of wetlands;– “Sites” included 1) areas with an expected high percentage of

isolated wetlands and 2) areas associated with major physiographicisolated wetlands and 2) areas associated with major physiographic regions

– Overall, isolated wetlands represented 23% of wetland area; for 11% of study sites, isolated wetlands represented >50% of wetland area;

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1) Will wetlands be disturbed, altered or destroyed by the proposed activity? If yes, indicate the number of acres that will be impacted.

2) If wetlands will be impacted, is mitigation proposed? If yes, submit a mitigation plan. If no, explain why not.

Mitigation - Mitigation means replacement of wetlands and their functions. It is required in the Corps process if alternative siting and efforts to reduce impacts still result in wetland loss.

Banking: Banking refers to the creation of artificial wetlands, storage of “credits” for these wetlands, and subsequent permission to destroy other wetlands with acreages less than the credits banked.

Problems with mitigation

• Created wetlands must be monitored for only 5• Created wetlands must be monitored for only 5 years;

• State agencies have not reviewed monitoring reports;

• States, ACE, EPA have provided little oversight or evaluation of replaced functions;evaluation of replaced functions;

• Mitigation sites may not be in same watershed;