Day 25 – Q 1. How are wetlands formed? What is their global distribution? Why are they so important for the ecosystem? Explain. (10 Marks)

  • IASbaba
  • February 24, 2022
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GS 1, TLP-UPSC Mains Answer Writing, World Geography
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1. How are wetlands formed? What is their global distribution? Why are they so important for the ecosystem? Explain. (10 Marks)

आर्द्रभूमि कैसे बनती है? उनका वैश्विक वितरण क्या है? वे पारिस्थितिकी तंत्र के लिए इतने महत्वपूर्ण क्यों हैं? समझाएं।


Candidates need to write about wetlands first. Then simply as per demand write how it’s formed and it’s global distribution. Also highlight it’s ecosystem importance before the conclusion. 


Wetlands are areas where water is the primary factor controlling the environment and the associated plant and animal life. They occur where the water table is at or near the surface of the land, or where the land is covered by water.


Formation of wetlands:

  • Flooding of coastal lowlands from rising sea levels has created broad coastal marshes that are protected from wave action by barrier islands or reefs. 
  • River floodplains develop through erosion processes and through deposition of sediment on adjacent lands during floods. 
  • Glaciers helped to create wetlands in the northern states 9,000-12,000 years ago. Large wetlands formed when glaciers dammed rivers, scoured valleys, and reworked floodplains. 
  • Wetlands may also form in “sink holes” and other areas where percolating water has dissolved bedrock. Earthquakes can create wetlands by damming rivers or causing land to drop down near the water table or shoreline. 
  • People create wetlands. Some “incidental” wetlands are formed when highway and dam construction, irrigation projects, or other human activities alter drainage patterns or impound water. 

Global distribution:

  • Mangroves such as the Sundarbans on the Ganges delta in India and Bangladesh, the Niger Delta complex in Nigeria and Cameroon, and the Orinoco and Gulf of Paria deltas on Venezuela’s east coast.
  • Salt marshes inland wetland systems develop saline conditions when the rate of evapotranspiration Scarborough Marsh and Morecambe Bay and Portsmouth in Britain and the Bay of Fundy in North America.
  • Tidal freshwater marshes tidal freshwater marshes include the St. Lawrence River between the United States and Canada, the Rhine and Thames rivers in Europe, and the Yellow River (Huang He) in Asia.
  • Peatlands Tropical peatlands are found in the lowlands of East Asia and Southeast Asia, the Caribbean, Central and South America, and Africa. 
  • Freshwater forested swamps are dominated by trees or other woody vegetation found for example from Delaware to Texas and along the Mississippi River. 
  • Riparian wetlands occur along rivers and streams that periodically overflow their channel confines, causing flooding to which the wetland vegetation is adapted. Occur in the Amazon Basin of South America, in Bangladesh, and in the floodplains of large rivers such as the Mississippi in the United States.


  • Wetlands are highly productive ecosystems that provide the world with nearly two-thirds of its fish harvest.
  • Wetlands’ microbes, plants and wildlife are part of global cycles for water, nitrogen and sulphur. Wetlands store carbon within their plant communities and soil instead of releasing it to the atmosphere as carbon dioxide.
  • Wetlands function as natural barriers that trap and slowly release surface water, rain, snowmelt, groundwater and flood waters. 
  • Wetland vegetation also slow the speed of flood waters lowering flood heights and reduces soil erosion.
  • They provide habitat for animals and plants and many contain a wide diversity of life, supporting plants and animals that are found nowhere else.


Effective collaborations among academicians and professionals, including ecologists, watershed management specialists, planners and decision makers for overall management of wetlands.

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