How Are Wetlands Defined and Identified Flashcards

Those areas that are inundated or saturated by surface or groundwater at a frequency and duration suffidient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions

1. Freshwater (bogs, marshes, fens, swamps, prairie potholes, vernal pools, pocosins
2. Saltwater (estuaries, tidal marshes, and mud flats)
freshwater wetlands are found in inland regions as opposed to salt marshes that are coastal in distribution

Too much water, not enough oxygen. denitrification has happened (crops stunted/not enough O2 to grow)

Woody vegetation, groundwater fed, minerotrophic, typically base-rich. may have some flooding, but driving force is streams that swamps usually have. can dry up at times. minerotrophic means fed by groundwater dissolving minerals along the flow path, typically circumneutral

Needs to flood at least every 1-2 years. has to happen long enough to change vegatation that can survive there (must be wet for 5% of growing season). dominance of certain type of plant community that can live under saturated conditions

Rainwater-fed, low nutrients, oligotrophic/acidic. not fed by ground or surface water - ponds draining out, not in. low in nutrients. highly acidic and oligotrophic (low N and P/poor minerals), lots of evergreens which are stress tolerant. pitcher plant can live here bc carniverous

Non-woody vegetation (herbaceous plants), surface water fed, minerotrophic to eutrophic (fairly nutrient rich). inputs = surface water, groundwater and runoff. can be saltwater (coastal) or freshwater (inland). minerotrophic = moderate nutrients, eutrophic is excess nutrients. lost of vegetation because of minerals

A soil that formed under conditions of saturation, flooding or ponding long enough during the growing season (5% of the growing season and the growing season is the last killing frost in spring to the first killing frost in fall) to develop anaerobic conditions in the upper part (top foot irrespective of horizons). The bacteria are not alive when it is too cold/outside of growing season. OM builds up, so darker top soil because NO3- redox itself won't change color of soil

Some wetlands receive mostly surface water inputs, others receive mostly groundwater inputs

Water must be "at" or "above" the ground surface for a significant portion of the growing season (may amount to only 2 or 3 weeks in some colder regions)

Wetlands protected federally under CWA. MA wetlands protection act - 1st state to do so. 1st protectors were sportsman (Ducks Unlimited) who wanted to protect bird habitat.

1. vegetation
2. water table
3. soils themselves

Common differences:
1. OM content: wetland soils have more SOM
2. Bulk density: Wetland soils have lower BD values (because of higher OM)
3. Hydraulic Conductivity: depending on degree of OM decomposition, wetland soil k-values are lower than upland soils (K depends on peaty or mucky soil - typically K low becuase mucky material is colloidal - humification is happening in waterlogged anaerobic soils)
4. Nutrient availability: Under natural conditions, wetland soils tend to be rather nutrient poor because of slow break-down process (depends on what is in the water)
5. CEC: if pH is raised to circumneutral levels, CEC of wetland soils is very high, greater than upland soil

Humus is pH dependent, pH about 7 = high CEC conditions. if acidic, humus not high CEC. histosol >20% SOM. 8-16" = histic epipedon. if O-layer <16 in, mineral soil wiht O layer

Under saturated, anaerobic conditions (common to wetland environments), microbial decay slows down significantly and organic matter accumulates in sediments. When a layer of soil contains >20% OM by dry weight, that layer is considered to be "organic matter"