Wetlands
ecosystem : significance, threat and conservation
Facts:-
--International
wetland day is 2nd Feb.
--Celebrated
since 1997 since Ramsar convection on 2nd Feb 1971 was signed and came into
effect.
--Ramsar
convention is not a part of UN but an international treaty.
--Ramsar
is a lake in Iran.
--
it is also known as waterfowl habitat.
--
wetlands are partially or completely submerged areas where water level is
high. It may be natural or manmade ,
coastal, inland, esturines, lacustraine, saline or freshwater waterlands, etc.
It includes paddy fields, bogs,rivers, marshy, swamps, mangroves, muddy
deltas,estuaries,creeks, saltpans, dams/reservoirs/barrages,
lagoons/backwaters/brackish lakes.
Geographical distribution of wetlands.
India
has diverse topography and climatic conditions producing different types of
wetlands. India has 4.7% of total geographical area under wetland ecosystem in
India. The 70% of wetland is in paddy fields, inland wetlands>> coastal
wetlands, India has total 15.2million hectares under wetlands.
According
to latest National wetland inventory and assessment project by MOEF&CC and
GIS survey by ISRO space application centre Ahmadabad.
Total area under wetland in the
country is estimated as 15.260 MHa by NWIA (National Wetland Inventory and
Assessment), 2011 which accounts for 4.63% of the geographical area. State-wise
distribution of wetlands showed that Lakshadweep has 96.12% of geographic area
under wetlands followed by Andaman and Nicobar Islands (18.52%), Daman and
Diu(18.46%) and Gujarat (17.56%), have the highest extent of wetlands.
Puducherry (12.88%), West Bengal (12.48%), Assam (9.74%), Tamil Nadu (6.92%),
Goa (5.76%), Andhra Pradesh (5.26%), and Uttar Pradesh (5.16%) are wetland rich
states. The least extents(less than 1.5 % of the state geographic area) have
been observed in Mizoram (0.66%) followed by Haryana (0.86%), Delhi (0.93%),
Sikkim (1.05%), Nagaland (1.30%), and Meghalaya (1.34%).
Inland – Natural Wetlands: Tamil Nadu
has highest number of lakes (4369) followed by Uttar Pradesh (3684) and West
Bengal (1327). Ox-bow lakes/Cut-off meanders are observed in Uttar Pradesh,
West Bengal, Bihar, Assam and Orissa. Large number of riverine wetlands exists
in Uttar Pradesh, West Bengal, Bihar, Assam and Jammu & Kashmir.
Inland – Man-made Wetlands: Andhra
Pradesh has highest number of reservoirs (4527) followed by Madhya Pradesh
(2005), Uttar Pradesh (1608), Orissa (1379) and Gujarat (1213). Details are
summarised below. Large number of Tanks/ponds exists in Tamil nadu,
Maharashtra, Madhya Pradesh, Andhra Pradesh, Rajasthan and Karnataka.
Small
wetlands ( less than 2.25 ha) : There are 555557 such wetlands exists in the
country. West Bengal has highest number of small wetlands (138707), followed by
Uttar Pradesh, Orissa, Madhya Pradesh, and Rajasthan.
India has a wealth of wetland
ecosystems distributed in different geographical regions. Most of the wetlands
in India are directly or indirectly linked with major river systems such as the
Ganges, Cauvery, Krishna, Godavari and Tapti. India has totally 27, 403
wetlands, of which 23,444 are inland wetlands and 3,959 are coastal wetlands.
According to the Directory of Asian Wetlands (1989), wetlands occupy 18.4% of
the country’s area (excluding rivers), of which 70 % are under paddy
cultivation. In India, out of an estimated 4.1 mha (excluding irrigated
agricultural lands, rivers and streams) of wetlands, 1.5 mha are natural, while
2.6 mha are manmade. The coastal wetlands occupy an estimated 6,750 sq km and
are largely dominated by mangrove vegetation. About 80% of the mangroves are
distributed in the Sunderbans of West Bengal and the Andaman and Nicobar
Islands, with the rest in the coastal states of Odisha, Andhra Pradesh, Tamil
Nadu, Karnataka, Kerala, Goa, Maharashtra and Gujarat.
Wetlands in southern peninsular India
are mostly manmade and are known as yeris (tanks). They are constructed in
every village and provide water for various human needs, besides serving as
nesting, feeding and breeding sites for a large variety of bird species. Point
Calimere in Tamilnadu; Ashtamudi, Sasthamkotta and Vembanad Kol lakes in
Kerala; and Kolleru lake in Andhra Pradesh are some of the natural wetland
sites in South India.
Wetlands significance
--- wetlands are significant due to it's all 4 ecosystem
service providing function such as provisional services, regulatory services,
Habitat services and cultural services..
--- wetlands are transition zone between land and
marine environment used for water conservation, purification of water
resources, remove contaminants, habitat for plants and animals, fisheries,
timber, medicines, sustainability of local community, agricultural productions
and food security, Birds breeding grounds, prevent coastal erosion and soil
erosion, etc.,
wetland services includes:
1) water storage by serving as natural rainwater
harvesting sites for example in cities of Mumbai entire water is supplied from
wetlands like modak sagar, Tania lake, Vihar lake,tulsi lake, vaitarana and
Bhatsa.
2) Bioshield for shoreline stabilisation , coastal
hazards like tsunami and cyclones and erosion control by
mangroves,lagoons,backwaters,etc.
3) Ground water recharge by wetlands as water
percolates into aquifers for example Udaipur has around 2500 lakes solved the
region’s water problem.
4) wetlands protect against storms and tool for flood
mitigation
5) water purification since , every water body has a
self cleaning system by removing cold bacteria, accumulating heavy metals of
arsenic,cadmium.
6) wetlands act as a buffer zone to retain sediment
and mineral nutrients. Soil and nutrition conservation.
7) wetlands used for stabilisation of local climatic condition such as
temperatures, moisture,cloud cover, carbon sequestration, carbon sinks,
humidity,
8) biodiversity hotspots, since wetlands are more
productive ecosystem, habitat for plants and animals. There are many wildlife
sanctuaries like Keoladeo, sariska wildlife sanctuary in Rajasthan, point
Calimere wildlife sanctuary in Tamil Nadu, Harike Pathan in Punjab. Bird
sanctuaries
Wetland Threats
--- wetlands are being destroyed, encroached,
polluted, fragmented, recharging blocked, deforested, landuse changes, silted,
etc., leads to reduction of wetland
services, water quality and quantity declines, migratory birds habitat loss,
biodiversity loss, fish depletion, vulnerability of local community increased,
waterbodies destroyed, developmental and settlement projects are harming the
ecosystem, urbanisation, anthropogenic activities, agricultural activities,
hydrological activities, deforestation, pollution, salination, aquaculture
activities, introduction of foreign species, climatic changes, etc
Wetland
conservation strategy
---
wetland conservation and protection under Ramsar convention of 1971 an
international treaty came into force in India on 1 Feb 1982 .,
---montreaux
record access the status of wetlands of IUCN threatened list,
---Ramsar
sites declared countrywise and trans-boundary wetland conservation , waterfowl
(bird) habitat conservation projects, in India 27 Ramsar sites are covering
around 1112131 hectares.
---since
1986 India lauched national wetland conservation programme (NWCP) which cover
more than 115 wetlands across India.
---
wetland conservation rules 2010 and it's amendment in 2017(new rules).
---
Integrated wetland conservation policy is required for regulations and usages
for ecology,forestry ,agriculture, food security, water and soil conservation,
preventing pollution and encroachment of wetlands, etc.
Ramsar
sites in India are 27 today. Last site added was on 1 Feb 2019 is Sunderban
wetland.
India
has designated Sundarban Wetland as a Wetland of International Importance, its
27th. The Site (Ramsar Site no. 2370) is located within the largest mangrove
forest in the world, the Sundarbans, that encompasses hundreds of islands and a
maze of rivers, rivulets and creeks, in the delta of the Rivers Ganges and
Brahmaputra on the Bay of Bengal in India and Bangladesh.
The
Indian Sundarban, covering the south-westernmost part of the delta, constitutes
over 60% of the country’s total mangrove forest area and includes 90% of Indian
mangrove species.