For Prelims: Ecosystems, mangroves, peatlands, and preservation of wetland areas

For Mains: The Value of Wetlands, Environmental Pollution, and Wetland Degradation, its advantages, and disadvantages. 

Why in News?

Humans have impacted every aspect of the Earth's ecosystem in this Anthropocene era. The disappearance of shallow wetlands like lakes and ponds is a significant concern due to these human-induced changes.

  • The most recent time in Earth's history when human activity began to have a noticeable impact on the planet's climate and ecosystem is referred to as the Anthropocene Epoch. This term refers to an unofficial unit of geologic time.

How do you define shallow-water wetlands?

About:

  • Permanent or semi-permanent bodies of water with little flow make up these wetlands. In addition to salt lakes and volcanic crater lakes, they also consist of vernal ponds and spring pools.
  • Inland fisheries and drinking water are just two examples of their enormous ecological significance.
  • The water body's shallowness allows sunlight to reach the bottom.
  • Isothermal temperature and a continuous mixing process are present, with the mixture frequently circulating from top to bottom, particularly in a tropical nation like India.

Concerns:

  • As time passes, sediments from the catchment fill these bodies of water.
  • This results in a gradual decrease in the depth of the water column. Any slight alteration in the temperature and rainfall pattern would cause this type of water body to experience a cascade of ecological effects.
  • India experienced a 0.7-degree Celsius increase in average temperature between 1901 and 2018. According to a 2020 Union Ministry of Earth Sciences report, the increase is attributed to warming caused by greenhouse gases and changes in land use and land cover.
  • The rainfall pattern will be affected by variations in regional temperature and heat distribution. India's natural ecosystems, freshwater resources, and agriculture are thus under threat, affecting biodiversity, food security, public health, and society as a whole.
    • Surajpur Bird Sanctuary is an example of an urban wetland in the Yamuna River basin. The Surajpur wetlands had low water levels, a high amount of algae growth, and odour and odour problems in October 2019.

What do we need to know about wetlands?

  • About:
    • Water plays a key role in determining wetlands' environment and plant and animal life. They manifest themselves where the land is submerged in water, or the water table is at or close to the ground's surface.
    • "Lands transitioning between terrestrial and aquatic ecosystems where the water table is typically at or near the surface or the land is covered by shallow water" is how wetlands are described.
    • Wetlands support millions by supplying food and water and regulating floods and storm surges. They are frequently referred to as "nature's kidneys" and "nature's supermarket."
  • Types:
    • Coastal Wetlands:
      • Beaches, mangroves, coral reefs, and other land-to-water transitions without river influence are examples of coastal wetlands.
      • The mangrove swamps found in protected tropical coastal areas are a good example.
    • Marshes:
      • These are characterised by herbaceous (non-woody) vegetation adapted to moist soil conditions and periodically saturated, flooded, or ponded with water. Tidal marshes and non-tidal marshes are additional classifications for marshes.
    • Swamps:
      • Swamps can be found in freshwater or saltwater floodplains. They are primarily fed by surface water inputs, with trees and shrubs predominating in vegetation.
    • Bogs:
      • Most of the water in bogs is from rainfall, and they are waterlogged peatlands found in old lake basins or depressions in the landscape.
    • Estuaries:
      • It is possible to find diverse biodiversity in the region where rivers meet the sea and the water changes from fresh to salt. Salt marshes, tidal mudflats, and deltas are some of these wetlands.

What are Wetlands Important for?

  • Highly Productive Ecosystems: Nearly two-thirds of the world's fish harvest is produced in extremely productive wetland ecosystems.
  • Integral Function in the Watershed's Ecology: The development of organisms that serve as the foundation of the food web and sustain numerous species of fish, amphibians, shellfish, and insects is made possible by the combination of shallow water and high nutrient levels.
  • Carbon Sequestration: The microbes, plants, and animals that inhabit wetlands are a crucial component of the water, nitrogen, and sulphur cycles on a global scale. Instead of releasing carbon dioxide into the atmosphere as carbon monoxide, wetlands store carbon within their plant communities and soil.
  • Lowering Flood Heights and Reduces Soil Erosion: Wetlands serve as organic barriers that slow down the release of floodwaters, groundwater, surface water, rain, snowmelt, and other liquids. Along with lowering flood heights and reducing soil erosion, wetlands' vegetation slows down flood waters' speed.
  • Critical to Life on Earth and Humanity: 40% of all species on Earth live and breed in wetlands, and more than a billion people rely on them for their livelihood.

What dangers exist for wetlands?

Urbanisation: 

  • On wetlands near urban centres, pressure is mounting to build residential, commercial, and industrial facilities. 
  • The preservation of public water supplies depends on urban wetlands.
  • According to estimates from the Delhi Wetland Authority, Delhi has more than 1,000 lakes, wetlands, and ponds.
  • However, the vast majority of these are in danger from invasive development—both intentional and unintentional—pollution from solid waste disposal and debris from construction projects.

Agriculture: 

  • Numerous wetlands have been transformed into paddy fields. The hydrology of the nearby wetlands was significantly changed by the construction of numerous reservoirs, canals, and dams for irrigation purposes.

Pollution: 

  • Wetlands function as independent water filters. They can only eliminate pesticides and fertilisers from agricultural runoff; they cannot eliminate mercury from factories or other kinds of pollution.
  • There is growing concern over how industrial pollution impacts wetlands' biological diversity and drinking water availability.

Climate Change: 

  • Wetlands may also be impacted by rising sea levels, changing precipitation patterns, more frequent storms, droughts, and floods, as well as increased atmospheric carbon dioxide concentrations.

Dredging: 

  • Dredging of streams lowers the local water table and dries out nearby wetlands by removing material from the riverbed or wetland.

Draining: 

  • By digging ditches into the ground, which collect and transport water out of the wetland, water can be removed from wetlands. This decreases the water table and dries out the wetland.

What steps are being taken to conserve wetlands?

  • Global-level initiatives:
    • To preserve and restore the terrestrial, aquatic, and marine ecosystems, the United Nations designated 2021–2030 as the Decade on Ecosystem Restoration.
    • World Wetlands Day
    • Ramsar Convention
    • Montreux Record
  • National-level initiatives:
    • Regulations for Wetlands (Conservation and Management), 2017.
    • Action Plan of MoEFCC

Steps to take 

  • To combat unplanned urbanisation and a growing population, the management of wetlands must take an integrated approach in terms of planning, carrying out, and monitoring.
  • Collaborations that are successful between academics and professionals, including ecologists, watershed management experts, planners, and decision-makers for wetlands management as a whole.
  • By launching programs to raise awareness of the value of wetlands and continuously checking the water quality of wetlands, essential steps can be taken to protect them from further deterioration.