wetlands are lands where saturation with water is the dominant factor determining the nature of soil...
Post on 23-Dec-2015
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Wetlands in the perspective of global change
Wetlands are lands where saturation with water is the dominant factor determining the nature of soil development and the types of plant and animal communities living in the soil and on its surface (Cowardin, December 1979).
Those areas that are inundated or saturated by surface or groundwater at a frequency and duration sufficient to support, and that 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 (Clean Water Act)
Types of wetlandsMarshes (soft-stemmed vegetation)Swamps (mostly woody plants)Bogs (freshwater wetlands, acidic, peat
deposits, evergreen trees and shrubs, sphagnum)
Fens (freshwater wetlands, fed by mineral-reach waters, neutral or alkaline, peat deposits, grassy vegetation)
North Florida saltmarshes
Formed along the edges of estuaries
Buffer against brief storm surges (protection of the shore against degradation)
Nurseries for fish, crustaceans, mollusks
Vasyugan swamp or bog (Western Siberia)
• The largest swamp in northern hemisphere (53,000 km²) formed 10,000 years ago, has been growing in size since then.
• Main source of freshwater in the region• Huge peat deposits (carbon sink)
Pantanal – tropical wetland
Wetland functions
Water storage and groundwater replenishment
Shoreline stabilityFlood controlWater filtrationBiological productivityCarbon storage (carbon sink)Methane production
Water storage and groundwater replenishment
Water is collected, stored and slowly released to aquifers or surface water
Shoreline stabilizationRoots anchor in sediment, preventing erosionVegetation diminishes the wave action
Flood control
Water filtration
Nutrient uptake (including excess from fertilizers etc.) and storage by plants
Sediment trapsBiofiltration and removal of toxic substances
by plant roots and bacteria
Biological productivityWetlands are among most productive
ecosystems in the world, comparable to tropical rainforests and coral reefs
Provide habitat to diverse species
Carbon storage
Methane production
Major global change agents influencing wetlands
Sea-level riseGlobal warmingDirect anthropogenic influence
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