Definition of wetland(s)
-Lands covered with water all or part of a year
-Interface between Terrestrial and aquatic ecosystems
- They have been called as 'nature's kidneys’
Characteristics of wetlands
• There are three characteristics that describe a wetland:
– There must be water at or near the surface of the land for a
designated amount of time.
– Must be hydric or saturated with water to create an anaerobic
– Must be “wetland plants,” meaning that they require lots of
water and the anaerobic conditions that the hydric soil creates.
(Smith & Smith, 2001)
Two components of hydrology
– Precipitation, surface
and subsurface flow,
and kinetic energy of
– Duration, frequency,
depth, and flood
Classification of wetland on the basis of hydrology
• Basin Wetlands (lakes and ponds)
– Physical: Water flow is vertical
– Hydroperiod: Long with floods during
periods of high rainfall.
• Riverine Wetlands (periodically flooded
banks of rivers and streams)
– Physical: Water flow is both vertical
and horizontal (precipitation and
– Hydroperiod: Have short periods of
flooding with stream/river flow.
Classification of wetland on the basis of hydrology
• Fringe Wetlands (along
coastal areas of large lakes
– Physical: Water flow is
both vertical and
and tidal flow)
– Hydroperiod: May be
short and regular. Is not
seasonal like basin
Three types of soils
1. Sandy soils
– Contain mineral grains ranging from 0.05-2 mm
2. Silt soils
– Soils that have grains ranging from 0.002-0.05
mm in diameter.
3. Clay soils
– Contain mineral grains smaller than 0.002 mm in
• Sandy soils
– Has good drainage and aeration
– Does not store water well
– Is not suitable for most plants
• Silt Soils
– Soils made from minerals
– Granule sizes are between sandy and
– Also known as “rock flour” or “stone
dust” when produced by glaciers
• Clay soils
- Hold water very well
- Do not drain water easily
- Do not have space for air
- Is not suitable for most plants
Native vs. Exotic
• If a plant is native to a particular area, then it is
originally from that area
– Native plants provide food and habitat for native animals.
Without this, the native animals may be forced to migrate to
– Native plants also keep local genes viable and in the gene
• Exotic plants were not originally in the area and have
been carried to the area in some way.
– Exotic plants can become invasive where they dominate the
ecosystem preventing opportunities for growth for the native
– Exotic plants also out grow native plants because they have no
– Invasive exotic species are the second leading cause of native
species extinction (habitat loss being number one).
Benefits of Aquatic Plants
• Primary Production
– Wildlife Food
– Oxygen Production
– 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
Submerged macrophytes can provide shelter for young fish as well as
house an abundant food supply.
Some fish will attach their
eggs to aquatic vegetation.
Alligators also build nests
Wetland Life – The Protists
• One celled organisms (algae, bacteria)
– Often have to deal with a lack of oxygen
• Desulfovibrio – genus of bacteria that can
use sulfur, in place of oxygen, as a final
– Produces sulfides (rotten-egg smell)
• Other bacteria important in nutrient cycling
• Single celled
• Base of aquatic food web
• Oxygen production
Solar Energy + CO2 + H20 C6H12O2 + O2
CO2 + H20 H2CO3
H+ + HCO3
- 2H+ + CO3
As CO2 is removed from the water pH increases.
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
• Emergent – herbaceous or woody plants that have the majority
of their vegetative parts above the surface of the water.
– Aquaculture ponds (e.g., fish/shrimp);
– Irrigated land (rice fields);
– Seasonally flooded agricultural
– Salt exploitation sites;
– Water storage areas;
– Excavations (gravel/brick/
– Canals and drainage channels;
– Wastewater treatment areas;
Description of some wetlands
• Very diverse group
• Non-tidal, freshwater systems
• Dominated by grasses, sedges, and other
freshwater emergent hydrophytes (non-forested)
• High productivity
• Approximately 20% of world’s wetlands
Freshwater Marshes Photo/ Example
Chemical Functions of Wetlands
• Pollution Interception
– Nutrient uptake by plants
– Settle in anaerobic soil and become reduced
– Processed by bacterial action
• Toxic Residue Processing
– Buried and neutralized in soils, taken up by
plants, reduced through ion exchange
– Large-scale / long-term additions can exceed a
– Some chemicals can become more dangerous
in wetlands (Mercury)
• Elemental mercury (Hg0)
– Most common form of environmental mercury
– High vapor pressure, low solubility, does not
combine with inorganic or organic ligands, not
available for methylation
• Mercurous Ion (Hg+)
– Combines with inorganic compounds only
– Can not be methylated
• Mercuric Ion (Hg++)
– Combines with inorganic and organic
– Can be methylated CH3Hg
• Basically a biological process by microorganisms in
both sediment and water
– Mono- and dimethylmercury can be formed
– Dimethylmercury is highly volatile and is not
persistent in aquatic environments
• Influenced by environmental variables that affect both
the availability of mercuric ions for methylation and
the growth of the methylating microbial populations.
– Rates are higher in anoxic environments,
freshwater, and low pH
– Presence of organic matter can stimulate growth
of microbial populations, thus enhancing the
formation of methylmercury
• Mercury is accumulated by fish, invertebrates,
mammals, and aquatic plants.
• Inorganic mercury is the dominate environmental
form of mercury, it is depurated about as fast as it is
taken up so it does not accumulate.
• Methylmercury can accumulate quickly but depurates
slowly, so it accumulates
– Also biomagnifies
• Percentage of methylmercury increases with
Chemical Functions of Wetlands
• Waste Treatment
• High rate of biological activity
• Can consume a lot of waste
• Heavy deposition of sediments that bury waste
• High level of bacterial activity that breaks down and
• Several cities have begun to use wetlands for waste treatment
Biological Functions of Wetlands
• Biological Production
– 6.4% of the Earth’s surface 24% of total
– Detritus based food webs
– 80% of all breeding bird populations along with
>50% of the protected migratory bird species
rely on wetlands at some point in their life
– 95% of all U.S. commercial fish and shellfish
species depends on wetlands to some extent
What happens when wetlands are destroyed?
• Destruction of wetlands can cause many
problems such as:
– Increased floods
– Water quality problems
– Population decrease in plants and animals that live in
Water storage and purification
Climate change mitigation
Loss of wetlands
• Building of dams
• Channelization of riverbeds
• Overexploitation of wetlands resources
• Introduction of invasive species
• Developmental activities and population pressure
• Water pollution and dumping of waste
• We have lost an estimated 50% of our
original wetlands in the world.
Wetlands in India
There are 19 different types of wetlands in India.
It includes mangroves, high-altitude lakes, marshes and ponds.
It covers an estimated 3 percent of India's land area.
Area Estimates of Wetlands of India (in million ha)
(Source: Directory of Asian Wetlands, IUCN, 1989)
Projects on Wetland Conservation in Uttarakhand
• The two conservation reserves – Jhilmil Jheel in Haridwar and Asan Barrage in
DehraDun districts – are being established under the 2003 parliamentary
amendment made in the Wildlife (Protection) Act 1972 with a view to seek
greater community involvement in protecting extremely critical wildlife.
• FRI Dehradun is engaged in a Wetland Conservation project.
• A special project undertaken by ZSI Northern Regional Circle, Dehradun for
conservation of Swamp Deer.
• Wild life institute of India Dehradun also played a pivotal role in Swamp Deer
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