Introduction to Wetland and Peatland

 A peatland is an area with a naturally accumulated layer of dead organic material (peat) at the surface. In most natural ecosystems the production of plant material is counterbalanced by its decomposition by bacteria and fungi. In those wetlands where the water level is stable and near the surface, the dead plant remains do not fully decay but accumulate as peat. A wetland in which peat is actively accumulating is called a mire. Where peat accumulation has continued for thousands of years, the land may be covered with layers of peat that are meters thick.

A wetland is an area that is inundated or saturated by water at a frequency and for a duration sufficient to support emergent plants adapted for life in saturated soil conditions. The Ramsar Convention also includes all open fresh waters (of unlimited depth) and marine waters (“up to a depth of six metres at low tide”) in its “wetland” concept. 

Peat is dead organic material that has been formed on the spot and has not been transported after its formation. 

A peatland is an area with a naturally accumulated peat layer at the surface. 

A mire is a peatland where peat is being formed. Wetlands can occur both with and without peat and, therefore, may or may not be peatlands. A mire is always a peatland. Peatlands where peat accumulation has stopped, e.g. as a result of drainage, are no longer mires. When drainage has been particularly severe, they are no longer wetlands.

Types of Wetlands:

MARSHES are periodically saturated, flooded, or ponded with water and characterized by herbaceous (non-woody) vegetation adapted to wet soil conditions. Marshes are further characterized as tidal marshes and non-tidal marshes.

SWAMPS are fed primarily by surface water inputs and are dominated by trees and shrubs. Swamps occur in either freshwater or saltwater floodplains. They are characterized by very wet soils during the growing season and standing water during certain times of the year. Well-known swamps include Georgia’s Okefenokee Swamp and Virginia’s Great Dismal Swamp. Swamps are classified as forested, shrub, or mangrove.

BOGS are freshwater wetlands characterized by spongy peat deposits, a growth of evergreen trees and shrubs, and a floor covered by a thick carpet of sphagnum moss. These systems, whose only water source is rainwater, are usually found in glaciated areas of the northern United States. One type of bog, called a pocosin, is found only in the Southeastern Coastal Plain.

FENS are ground water-fed peatforming wetlands covered by grasses, sedges, reeds, and wildflowers. Willow and birch are also common. Fens, like bogs, tend to occur in glaciated areas of the northern United States.

Importance of wetlands:

Wetlands ensure fresh water for us all. Only some 3 % of the world’s water is fresh, with most of that frozen. Only 1% of that, or 0.03% of total water, is available for direct use by people. Yet every human needs 20-50 litres of water a day for basic drinking, cooking and cleaning with astronomically higher requirements to grow the food eaten. Wetlands provide that water, and help replenish groundwater aquifers. 

Wetlands purify and filter harmful waste from water. Plants from wetlands help absorb harmful fertilizers and pesticides, as well as heavy metals and toxins from industry. The Nakivubo Swamp in Kampala, Uganda, for example, filters sewage and industrial effluents for free; a treatment plant would cost $2 million per year. 

Wetlands feed humanity. Rice, grown in wetland paddies, is the staple diet of nearly three billion people. The average human consumes 19 kg of fish each year. Most commercial fish breed and raise their young in coastal marshes and estuaries. 70 % of all fresh water extracted globally is for crop irrigation.

Wetlands burst with biodiversity. Wetlands are home to over 100,000 known freshwater species. That number is growing. In just 10 years, 272 new species of freshwater fish were discovered in the Amazon alone. Wetlands are essential to bird life, breeding and migration. 

Wetlands act as nature’s sponges. Peatlands, wet grasslands and floodplains in river basins act as natural sponges by absorbing rainfall and creating wide surface pools that ease flooding in rivers. The same storage capacity can also safeguard against drought. 

Wetlands help fight climate change. Peatlands alone store more than twice as much carbon as all the world’s forests. Faced with rising sea levels, coastal wetlands reduce the impact of typhoons and tsunamis. They also bind the shoreline and resist erosion. 

Wetlands provide sustainable livelihoods and products. Some 62 million people depend directly on fishing and fisheries for a living. Timber for building, vegetable oil, medicinal plants, animal fodder, and stems and leaves for weaving can all originate from sustainably managed wetlands.

Drivers of wetland loss: 

Often viewed as wastelands to be drained, filled and converted to other purposes, the main causes of wetlands loss and degradation include major changes in land use, especially an increase in agriculture and grazing and urban infrastructure development, air and water pollution and excess nutrients, and water diversion (dams, dikes and canalization).

https://www3.epa.gov/owow/RealEstate/reading/TypesofWetlands.pdf

https://www.wetlands.or.id/PDF/chapter_1-3.pdf

https://www.cbd.int/waters/doc/wwd2015/wwd-2015-press-briefs-en.pdf