Over 14K wetlands gained, over 1,300 lost in a decade: updated Wetland Atlas

There has been an addition of 14,823 new wetlands with an area of 0.36 Mha between 2006-07 and 2017-18, while a total of 1,342 wetlands covering an area of 0.025 Mha have disappeared, according to an updated Wetlands Atlas launched on Wednesday.

In absolute numbers, there has been a total increase of 0.64 million hectares (Mha) area and 18,810 wetlands. The increase in wetland area includes both new (56.4 per cent) as well as positive change in the existing wetlands (43.6 per cent). Among the wetlands that disappeared in the 2017-18 document, are mostly waterlogged regions (natural and man-made), tanks in abandoned mining, and aquaculture ponds.

These are the findings of the ‘National Wetland Decadal Change Atlas’ that was released on the occasion of World Wetlands Day 2022 on Wednesday.

Formally named ‘Space Based Observation of Indian Wetlands’, the Atlas is a documentation of wetlands across India, especially with respect to the changes from 2006-07 till 2017-18. Like the one from 2006-07, this too has been prepared by the Space Applications Centre of the Indian Space Research Organisation, Ahmedabad.

At the national level, the total wetland area has been estimated at 15.98 Mha, which is around 4.86 per cent of the total geographic area of the country. A total of 2,31,195 wetlands (of area more than or equal to 2.25 ha) have been mapped at 1:50,000 scale during 2017-18.

The major wetland types in terms of area coverage are rivers/streams, reservoirs, intertidal mud flats and tanks/ponds. Among the wetland types, more than one third of the total wetland area is covered by rivers (35.2 per cent), another around 43 per cent wetland area is covered combining reservoirs (17.1 per cent), intertidal mud flats (14.4 per cent), and tanks/ponds (11.4 per cent).

In addition to the various types of natural wetlands, a large number of man-made wetlands also contribute to the faunal and floral diversity. These man-made wetlands, which have resulted from the needs of irrigation, water supply, electricity, fisheries and flood control, are substantial in numbers.

Many of tanks/ponds are rural tanks, check dams, ash ponds/cooling ponds or abandoned mining areas. Rural India is speckled with numerous natural and man-made ponds of varied shapes, size and depth. Though many of them are seasonal, they play an important role in providing habitat and support to biodiversity.

The total number of reservoirs in the country is 12,802 (5.5 per cent of total wetlands), covering 2.74 Mha area whereas tanks/ponds are 1,51,815 (65.7 per cent of total wetland numbers), covering 1.81 Mha area.

In comparison to earlier wetland inventory of 2006-07, the latest document showed a total increase of both area and numbers.

A majority of increase in wetland area has been found in inland man-made (81.5 per cent) and coastal man-made (17.0 per cent) categories.

A total of 14,823 new wetlands were added with an area of 0.36 Mha and out of this more than (93 per cent) are inland wetlands. There is a steep rise in the tanks/ponds (10,341, 0.085 Mha), reservoirs (1,343, 0.186 Mha) and aquaculture ponds (1,872, 0.058 Mha)

New wetlands mostly include tank/ponds, abandoned mining areas, reservoirs, aquaculture ponds and riverine.

Total 1,342 wetlands, which were existing earlier and covering an area of 0.025 Mha, disappeared in 2017-18. These are mostly waterlogged regions (natural and man-made), tanks in abandoned mining, and aquaculture ponds.

There is decrease in coastal natural wetlands, which are mostly converted to coastal man-made category with major change to intertidal mud flats, which are converted to salt pans in Rann of Kachchh.

There is an increase in the mangroves area (3.8 per cent, 18,662 ha). Most of the intertidal mud flats are converted to mangroves.

There is an increase in coral reefs area (2,784 ha, 1.9 per cent), which is mainly in Kachchh (1,881 ha) and Andaman and Nicobar Islands (892 ha).

The major positive change in the wetland area obtained in salt pans-coastal (58 per cent), aquaculture ponds-inland (55.3 per cent), salt pans-inland (49.2 per cent), reservoirs (12.8 per cent), and high-altitude wetlands (7.4 per cent).

Major increase in numbers of different wetland types includes salt pan-coastal (130.8 per cent), aquaculture ponds-inland (60.3 per cent), mangroves (30.3 per cent), aquaculture ponds-coastal (27 per cent), salt marshes (16.5 per cent), salt pan-inland (25 per cent), reservoirs (14.7 per cent) and tanks/ponds (9.0 per cent).

The major negative change in wetland area was observed for intertidal mud flats (4.8 per cent), salt marshes (3.7 per cent), and waterlogged (2.4 per cent).

The Atlas delineated a total 20 types of wetlands. The wetland classification categorises inland and coastal at level I, followed by natural and man-made wetlands as level II, which were further categorised into 20 types of wetlands as level III classes.

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