Wetlands at a loss in India
According to the survey conducted by Wildlife Institute of India, 70 to 80 percent of fresh water marshes and lakes in the gangetic flood plains have been lost during the last 50 years. As a matter of fact, during the last century, 50 percent of India’s wetlands have been lost.
Wetlands consist of marshes, swamps, bogs and similar areas. It helps in filtering out of sediments and nutrients from the surface water and support all life forms through extensive food webs and biodiversity.
Wetlands contribute to a number of important processes including movement of water into streams and rivers, decay of organic matter, release of sulphur, nitrogen and carbon into the atmosphere and the growth and development of different types of organisms.
The direct benefits that human beings derive from wetlands include production of fish, timber and fresh water. The indirect benefits include flood control, recharge of aquifer and storm protection. Wetlands have the capacity to retain excess floodwater during heavy rainfall. Wetland vegetations help control soil erosion, thus stabilising the shore line and protecting human lives from storm.
Wetlands occupy nearly 6.4 percent of the earth’s surface. About 50 per cent of the world’s wetlands have been lost due to careless human activities like urbanisation, drainage for agriculture and water system regulations and developmental activities like industrialisation, excavation and filling and drilling.
India has got 67,429 wetlands covering an area of 4.1 million hectares. Out of these wetlands, 2175 are natural and the rest 65,254 are man-made.
The wetlands of India, have been drained and transformed by anthropogenic activities like unplanned development of urban and industrial sites, agricultural activities, construction of highways, impoundments, resource extraction and dredge disposal, causing long term economic and ecological loss.
According to the survey conducted by Wildlife Institute of India, 70 to 80 percent of fresh water marshes and lakes in the gangetic flood plains have been lost during the last 50 years. As a matter of fact, during the last century, 50 percent of India’s wetlands have been lost. The mangrove area of the country has been reduced from 7 lakh hectares in 1987 to 4.53 lakh hectares in 1995.
About 32 percent of the wetlands in India has been lost primarily through hunting and associated disturbances, 22 percent due to human settlements, 19 percent due to fishing and 23 percent through drainage from agriculture. Removal of vegetation in the catchment leading to soil erosion and siltation, contributes to about 15 per cent loss of wetlands. Pollution from the industries contributes to about 20 percent loss of wetlands.
Some of the major human activities responsible for the destruction of wetlands in India include hydrologic alteration, agricultural activities, pollution, legal-policy failures, direct deforestation in wetlands, inundation by dammed reservoirs, degradation of water quality, global climate change effects, ground-water depletion and introduction of exotic species.
The conversion of wetlands, deltas and flood plains of most rivers in India to paddy fields is rampant, following “Green revolution” of the early 70’s. It is an ecological irony that as a result of this, the gross spatial extent of wetlands in the Indian subcontinent is greater today than it was 3,000 years ago owing to increased paddy fields treated as wetlands. The natural coastal wetlands are polluted to the extent that their fishery and recreational values are almost lost.
The loss of wetland forests reduces the ability of wetlands to trap suspended sediments. The erratic alterations of impounded water levels, the potential for shoreline wetlands to develop and mitigate the losses of river bottom and riparian zones is minimal.
As a result of variable dam releases for power generation, the wetter area do not follow a predictable seasonal pattern, precluding development of a stable wetland flora and wildlife community.
Wetlands both contribute to and suffer from climate change. They are the single largest source of methane, a gas that is a major contributor to global warming.
In view of the above scenario, it is very essential to properly manage the wetland of India, so that these invaluable resources can be properly utilised for our socio-economic development and for keeping our environment healthy.