Wetlands
Common Wetland Plants
Herbaceous (nonwoody, soft-stemmed plants) Shrubs (low woody plants with several studies) Trees (woody perennials with one main stem or trunk and branches)
Support downstream aquatic systems
Produce food and organic material that flows into adjacent streams during high flows and nourishes adjacent habitats
Coastal
5% of wetlands marine - saltwater estuarine - mixture of salt and fresh water (brackish)
Inland or freshwater
95% of wetlands
Bog
Acidic, peat-accumulating wetland with no significant inflow or outflow of water; water mostly from precipitation; soil is saturated with water: very little oxygen -> very few soil microorganisms; common in cold climates: Maine, Vermont, Wisconsin, Michigan
Provide areas of recreation and beauty
Bird watching, fishing, hiking, canoeing, hunting, photography
Freshwater marsh or swamp
Border rivers, creeks, ponds, lakes, and isolated depressions; water source comes from precipitation, flooding from adjacent water bodies, groundwater seep; marsh: nonwoody vegetation that floats on water, emerges from water, or is submerged in water; swamp: woody vegetation (trees and shrubs)
Wetland Plants
Called hydrophytes Hydrophilic - water loving Adapted to living in wetlands: fluctuating water levels (even flooding), low oxygen availabilty
Salinity
Concentration of dissolved salts in water Fresh water (0-.05 ppt) Brackish (0.5- 30ppt) Salt water (>30 ppt)
Organic soils
Contain a lot of partially decayed plant and animal material that forms a thick black layer of peat or muck, develop in cool, northern regions that are saturated with water for most of the year, water saturation and low oxygen inhibit microorganisms growth and thus inhibit decomposition
Mineral Soils
Contain mostly inorganic matter, sand, silt, clay, form in warm, wooded wetlands that are saturated for only a portion of the season (Georgia), very little decaying organic matter because decomposition is able to "keep up"
Characteristics of Wetland Plants
Cypress knees jutting out of ground and above water; trees with swollen or buttressed tree trunks at height of deepest water level (water line); plants with hollow tubes or sacs that transport oxygen from leaves and stems to roots; plants with shallow or exposed roots; floating plants with roots that dangle in water; spanish moss growing in trees and getting its moisture from the air
How do we recognize hydric soils?
Dark gray, dark brown, black or green color (may be gleyed or mottled), sulfurous or rotten egg smell, feels wet and sticks together (holds together and makes a ball, makes a ribbon that can stay intact if let hang)
Wetland Delineation
Determining where a wetland starts and ends: important because wetlands provide valuable ecological and economic functions
Herbaceous
Emergent: rooted in soil but have stems, leaves, flowers above water surface Floating: rooted in soil or free-floating with leaves on water surface and flowers just above Submergent: grow completely beneath surface
Furnish natural products
Fish and shellfish; rice, cranberries, blueberries; grasses for baskets and chair caning; sphagnum moss for gardening; timber (tupelo, cypress); furs and hides (beaver, muskrat, mink, otter, alligator)
Mottled
Formed in areas that have wet (anaerobic) conditions followed by periods of dry (aerobic) conditions Splotches of brown, orange, red, or yellow Form when minerals such as iron become oxidized when the soil dries out (iron reacts with oxygen)
Gleyed
Formed when soil is saturated all of the time (anaerobic conditions), gray, greenish, bluish-gray
Classification of Mineral Soils
Gleyed and mottled
Three Characteristics that define or delineate wetlands
Hydric (water-saturated) soil Anaerobic (low oxygen) soil Hydrophytic (water tolerant) plants
Functions of Wetlands (cont'd)
Improve water quality by filtering and trapping nutrients, wastes, sediment, and pollutants from surface runoff before they enter larger bodies of water; slow down water flow and help prevent erosion and deposition of sediment in water bodies; soak up floodwaters and slowly release water back into the system, thus preventing downstream floods
Carolina Bay
Isolated wetlands in coastal plains of North Carolina, South Carolina, Georgia; Shallow, oval depressions fed by rain and shallow ground water; 30,000-100,000 years old; origin uncertain
Playa
Isolated, temporarily, shallow, often circular freshwater ponds in Great Plains; dependent on rainfall and runoff; West Texas Panhandle, Colorado, New Mexico, Nebraska, Kansas, Oklahoma; provide resting habitats for migrating shorebirds, ducks, geese, cranes, songbirds; recharge the Ogallala Aquifer (world's largest)
Bottomlands
Lowlands located along rivers and streams; become flooded when rivers and streams overflow
Prairie Pothole
Midwest North America; thousands of tiny lakes, ponds, marshes; formed when last ice age retreated, leaving small water-filled depressions; stopover habitat migrating waterfowl
Saltwater marsh
Occurs alongside the coast, periodically flooded by saline or brackish water due to tides, salt-tolerant plants (halophytes)
Classification of Hydric Soils
Organic soils and mineral soils
Wet Tundra
Peat bogs found in Alaska and Canada
Functions of Wetlands
Provide areas for education and research Inspire fine arts and literature Preserve cultural heritage and archaeological evidence Provide areas of recreation and beauty Furnish natural products Support downstream aquatic systems Provide habitat for many species Recharge groundwater supplies
Clean Water Act of 1972
Restore and maintain the chemical, physical, and biological integrity of the nation's water
Slow down water flow and help prevent erosion and deposition of sediment in water bodies
Roots and stems of wetland vegetation bind sediment: sediment deposition clogs gills of fish and other aquatic organisms, blocks sunlight needed for photosynthesis, and destroys spawning areas Coastal wetlands protect shorelines from erosion by dissipating waves and currents
Categories of Wetlands
Salinity Inland or freshwater Coastal
Mangrove swamp
Salt to brackish water located along rivers as they approach the ocean, tropics and subtropics (Florida and Hawaii), dominated by large mangrove trees (large, multibranched mats of air roots)
Soil Texture and Soil Permeability
Soil particles = sand (largest particle and largest pore space), silt, clay (smallest particle and smallest pore space) Pore space affects water percolation rates (water percolates faster through sand than clay because sand has bigger holes (pore spaces)) Permeability is the rate at which water percolates through soil: the slower the percolation rate, the less permeable the ground; sandy soils are more permeable than clay soils; soils with a high percentage of clay have low permeability and make excellent wetland soils
Hydric Soils
Soils that are periodically or permanently saturated with water; in nonhydrolic soils, oxygen is located in pore space between soil particles but in hydric soils, the pore space is filled with water, so there is no room for oxygen; microorganisms in hydric soils must be able to live without oxygen, use anaerobic respiration to break down organic molecules, use sulfur or nitrates instead of oxygen
Signs of Wetlands
Spongy or mushy ground; mud or dried mud cracks; water staining on trees (water line); mottled or darkly stained vegetation; depressions where water might collect; topographic evidence of water paths (gullies); cypress knees (air roots); buttressing of trees; spanish moss
Mitigation
The creation, restoration, enhancement, or preservation of another wetland for the purpose of providing compensation for damaging or destroying a wetland
What are wetlands?
Transitional areas between dry land and aquatic systems (streams, rivers, lakes, oceans); areas that are saturated/ filled by surface water or groundwater frequently enough and long enough to support plants that are adapted to wet soil conditions
Provide habitat for many species
Up to 45% of wetland species are rare and endangered Shelter and nesting sites for waterfowl Resting and "refueling" stations for migratory birds Spawning and nursery habitats for fish, shellfish, etc
Recharge groundwater supplies
Water stored in wetlands slowly percolates into underlying aquifers
Preserve cultural heritage and archaeological eveidence
Wetland conditions and thick layers of organic matter retard decomposition Cape Canaveral, Florida: Native American burial ground, >7000 years old, 150 individuals
Wetland and Species Diversity
Wetland sustain 1/3 of US threatened and endangered species; wetlands provide habitat for 1/3 of resident bird species and 1/2 of migratory bird species; wetlands provide feeding, spawning, and nursery grounds for 1/2 of fish harvested in US (marine and freshwater)
Wetland Facts
Wetlands are located all over the world and in every state in the US: 6% of earth's land surface is classified as wetland; US states with the most wetland: Alaska, Florida, Louisiana Distribution of US wetlands: 5% coastal wetlands, 95% inland wetlands US has lost over 50% of our wetlands: agriculture, urban development, mining
How can we protect wetlands?
Wetlands are protected by the Clean Water Act of 1972, we can remove barriers (such as dams) to allow water to return to its proper flow, wetlands damaged or lost to development can be mitigated