Wetlands provide important ecosystem services but face many threats. On-site threats include draining wetlands for agriculture, dumping waste, and pollution from nearby activities. Off-site threats involve upstream deforestation, dams altering water flows, and pollution from distant sources. A key threat is conversion to aquaculture through draining or filling wetlands. Wetlands are drained and filled to make way for shrimp or fish farms, eliminating natural habitat.
2. Wetlands are...
A wetland is a distinct ecosystem that is inundated by water, either permanently or
seasonally, where oxygen-free processes prevail. The primary factor that
distinguishes wetlands from other land forms or water bodies is the characteristic
vegetation of aquatic plants, adapted to the unique hydric soil.
3. Under the Ramsar international wetland conservation treaty, wetlands are defined as
follows:
Article 1.1: "...wetlands are areas of marsh, fen, peat land or water, whether natural
or artificial, permanent or temporary, with water that is static or flowing, fresh,
brackish or salt, including areas of marine water the depth of which at low tide does
not exceed six meters."
Article 2.1: "[Wetlands] may incorporate riparian and coastal zones adjacent to the
wetlands, and islands or bodies of marine water deeper than six meters at low tide
lying within the wetlands."
Ramsar Convention definition
@1971
4. Wetlands – lands covered with water all or part of a year
Hydric (saturated) soils – saturated long enough to create an anaerobic state in the
soil horizon
Hydrophytic plants – adapted to thrive in wetlands despite the stresses of an
anaerobic and flooded environment
Hydrologic regime – dynamic or dominant presence of water
5. General Types of Aquatic Macrophytes
Submergent – Plants that grow entirely under water. Most are rooted at the
bottom and some may have flowers that extend above the water surface.
Floating-leaved – Plants rooted to the bottom with leaves that float on the
water surface. Flowers are normally above water.
Free Floating – Plants not rooted to the bottom and float on the surface.
Emergent – herbaceous or woody plants that have the majority of their
vegetative parts above the surface of the water.
11. Benefits of Aquatic Plants
Primary Production
Wildlife Food
Oxygen Production
Shelter
Protection from predation for small fish
Fish Spawning
Several fish attach eggs to aquatic macrophytes
Some fish build nests in plant beds
Water Treatment
Wetland plants are very effective at removing nitrogen and phosphorous from
polluted waters
13. Some fish will attach their
eggs to aquatic vegetation.
Alligators also build nests
from vegetation.
14. Wetlands of Rajasthan
Name Designated Area(km2)
Keoladeo National Park 01/10/1981 28.73
Sambhar Lake 23/03/1990 240
15. Land birds
Among land birds are a rich assortment consisting of warblers, babblers, bee-
eaters, bulbuls, buntings, chats, partridges and quails. Grey hornbill and
Marshall's iora are also present.
There are many birds of prey including the osprey, peregrine, Pallas' sea eagle,
short-toed eagle, etc..
Greater spotted eagle has recently been recorded breeding here, a new breeding
record for the species in India.
16. The Sambhar Lake,
India's largest inland salt lake, a bowl shape lake encircles historical
Sambhar Lake Town located 96 km south west of the city of Jaipur
(Northwest India) and 64 km north east ofAjmer.
17. Economic importance
It is India's largest saline lake and is the source of most of Rajasthan's salt
production. It produces 196,000 tones of clean salt every year, which equates to
around 9% of India's salt production. Salt is produced by evaporation process of
brine and is mostly managed by Sambhar Salts Ltd.(SSL), a joint venture of the
Hindustan Salts Ltd. and the state government.
Ecological importance
Sambhar has been designated as a Ramsar site (recognized wetland of international
importance) because the wetland is a key wintering area for tens of thousands of
flamingos and other birds that migrate from northernAsia.
The specialized algae and bacteria growing in the lake provide striking water colors
and support the lake ecology that, in turn, sustains the migrating waterfowl.
21. Human threats : On site On site
Drainage for agriculture, forestry
•Control of mosquitoes/diseases
•Dredging, channelization
•Filling for solid waste disposal, commercial, residential, industrial
areas
•Conversion for aquaculture and other land uses
•Discharges of pesticides, herbicides, nutrients, sediment, toxicants
from domestic sewage, agricultural, aquaculture & livestock runoff,
industries
•Inappropriate restoration techniques
22. •
Mining of wetland soils for peat, coal, clay, sand, gravel, minerals,
gemstones, phosphate and other materials
•Introduction of alien invasive species
•Groundwater abstraction
•Non-wise use activities / patterns, illegal hunting, inappropriate
fishing practices, over-exploitation of wetland resource
•Changing life style, cultural perception and behavior towards wetland
conservation
•Tourism
•Burning, fires
•Construction of roads, dikes, dams, etc.
•Others ……………..
23. Human actions : Off site
•
Deforestation, degradation of upper-watershed
•Inappropriate land uses in upper-watershed
•Sediment diversion by dams, deep channels
•Hydrological alterations by roads, barriers encircling wetlands
•Pollution of all forms e.g. from industries, agriculture, communities, urbans,
etc.
•Over-extraction of groundwater
•Minings(inland & off-shore), sand pumping, mineral, oil/gas extraction
subsidence
•Mega-projects, infrastructures development e.g. dams, roads, power plants,
etc.
•Population growth
pressure on wetlands