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Sansad TV: Nature Connection- ‘Mangroves’, sentinels of the ecosystem

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Introduction:

Mangroves are one of the most valuable ecosystems on our planet Earth. Mangroves are found in coastal areas and play an important role in protecting coastlines, maintaining water quality and providing habitat to marine species. Mangroves are truly a miraculous gift of nature as they not only prevent soil erosion in coastal areas but also protect the land from becoming salty due to the sea.

  • Mangroves are the characteristic littoral plant formation of tropical and subtropical sheltered coastlines. They exhibit remarkable capacity for salt water tolerance, strong wind velocity, varying tides and high temperature (FAO-1952). Eg :Rhizopora, Avicenia, Bruguiera etc.

Ecological Services by Mangroves

  • Flood control
  • Groundwater refill
  • Shoreline stabilization & storm protection
  • Sediment & nutrient retention and export
  • Water purification
  • Reservoirs of biodiversity
  • Cultural values
  • Recreation & tourism
  • Climate change mitigation and adaptation

Threats to Mangrove Cover

Man-made activities

  • Irresponsible tourism brings with them garbage, sewage, noise, fumes, lights, and other disturbances that can damage mangroves and its biodiversity.
  • Coastal Development leading to increasing pollutants and conversion of mangrove cover.
  • Pollution: Mangroves are being destroyed and facing severe threats due to urbanization, industrialization, and discharge of domestic sewage, industrial effluents and pesticides.
  • The rapid expansion of shrimp aquaculture on India’s flat coastal lands has been an important cause of conversion of mangroves. Eg : In Godavari delta area, about 14 percent of the aquaculture farms have been constructed on mangrove lands (FAO).
  • Nearly 40 per cent of mangrove forests in West Coast of India have been converted into farmlands and housing colonies over the last three decades.

Climate Change

  • Increase in sea level leading to inundation of mangroves and decreasing nutrients from freshwater. Mangroves are adapted to specific tidal regimes.
  • Shore line erosion receding mangrove covers. Mangroves shows Zonation and this gets disturbed.
  • Cyclones and storms cause defoliation in mangroves leading to mortality.
  • Changing sea temperatures disrupts the mangrove succession.
    • Eg: Avicenia and Sonneratia(pioneer species) –>Rhizopora–>Bruguiera

Role and Significance of Mangroves

  • Mangroves moderate monsoonal tidal floods and reduce coastal inundation.
  • It prevents coastal soil erosion.
  • It supplies firewood, medicinal plants to local inhabitants.
  • They support numerous flora, avifauna and wildlife.
  • Mangroves support seashore and estuarine fisheries.
  • It protects inland agricultural lands, livestock and coastal lands from hurricane and tsunami effect.
  • Mangroves enhance natural recycling of nutrients.
  • Mangroves are flood buffers and they also help in stabilizing the climate by moderating temperature, humidity, wind and even waves
  • They are natural carbon sinks.

Scientific Management of Mangroves

  • Nationwide mapping of the mangrove areas, by remote sensing techniques coupled with land surveys, and time series to assess the rate of degradation of the ecosystems.
  • Quantitative surveys of area, climatic regime, rate of growth of forest trees and seasonal variations of environmental parameters.
  • Inclusion of mangrove species under threat in the IUCN (International Union for Conservation of Nature) Red list. Eg Sonneratia griffithii in India
  • Assessment of suitable sites for reserve forests. Eg: Artificial regeneration through mangrove nurseries or aerial seeding.
  • Joint management of mangroves with local community participation.
  • Disease and pest control. Eg : Crab cuts are prevented by painting hypocotyls in yellow or Placing seedlings inside bamboo containers.
  • Afforestation of degraded mangrove areas;
  • Study of management methods, the ecology of mangroves, their flora and fauna, their microbiology and the biochemistry of organic matter and sediments.
  • Mangroves for Future is an unique partner-led initiative for coastal ecosystem conservation. This project is being coordinated by the International Union for Conservation of Nature (IUCN) covering, initially, eight countries (including India) in South Asia, South East Asia and Western Indian Ocean, for the protection of the mangroves.

The mangroves have been afforded protection under Category I (ecologically sensitive) of the CRZ.

Conclusion

An increase of 54 sq Km in mangrove cover has been observed. There is a need to build on this progress for stabilization of low-lying coastal lands. Mangroves being natural filters of pollutants from water, it becomes even more necessary to conserve them.