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Biodiversity
Conservation of Freshwater Ecosystem in India
By:
S.K.
Kulshrestha
Introduction
Biodiversity
includes assemblage of plants,
animals and micro-organisms; their genetic
variability expressed in varieties and
populations; their habitats, ecosystems
and natural areas, the mosaic of which gives richness to the natural
environment. Biodiversity or biological resources provide
food, clothing, housing, medicine and spiritual nourishment to human beings.
Apart from the rich flora,
having
7% of the 89,500 animal species, found in the world. The loss to Indian
biodiversity is mainly from habitat destruction,
over-harvesting, pollution and inappropriate
introduction of exotic plants and animals.
As
stated in ‘Global
Biodiversity Assessment’, published
by the UNEP, "unless action is taken to protect biodiversity, we
will lose forever the opportunity and the most precious assets
of natural resources, available to the mankind." Biodiversity
conservation is of critical importance as it may be of
direct or indirect benefit to mankind.
Among
major biodiversity countries, the
number of species of higher plants in Brazil
is 55,000 followed by Columbia 35,000,
China
South
Africa
23,000, former Soviet Union
22,000,
20,000,
United States of America 18,000, Australia
15,000 and
15,000.
Freshwater Resources
Over
99% of biosphere water occurs in oceans and polar ice deposits, out
of which 97.61% occurs in oceans. The freshwater is mainly in the form
of ice, snow and ground water, 0.009% in freshwater lakes, 0.0009% in
atmospheric water vapour and 0.00009% in rivers. Only 0.01% of the
global freshwater is available in rivers, lakes and
reservoirs. The dam reservoirs contain five times
as much water as in rivers. The surface
waters sustain freshwater biodiversity,
perform ecological functions and support human
needs such as agriculture, hydro-electricity, industry, sewage and
sanitation, aquaculture, fisheries, drinking water, transportation,
recreation and spiritual needs, etc. About 54% of accessible surface run
off
is used. About 45,000 species of freshwater organisms are
known while about one million are yet to be discovered. Major
organisms include viruses, bacteria, diatoms, plants and animals from
protozoa to mammals. Freshwater organisms constitute about 25% of the
total number of organisms.
Aquatic
bacterial diversity knowledge is
increasing rapidly. Almost 20% of the fishes, found globally, are extinct,
vulnerable or endangered. The rich endemic ichthyofauna of African
Lake
, Victoria
,
has been reduced by exotic predatory
eutrophication. Groundwaters, as deep
as 2.8 Km, may have rich bacterial flora. According to World
Bank, 80 countries with 40% of the
world’s
population have water shortage that could cripple agriculture and industry. Fish diversity is threatened by construction of dams, hydro-electric facilities,
channelization projects and
invasion of non-native biota. The
Ganges and Brahmaputra rivers carry
more than 3 billion metric tons
of soil to the
Bay of Bengal each year, spreading it
over 3 million sq. km of sea bed.
Benefits from Freshwater Biodiversity
Freshwater
biodiversity provides benefits to
humans. This includes inland water fishing for food, aquaculture
production, ornamental fish trade, recreational
fishing, rice farming, harvest of a variety of other living
resources, medicinal plants, fuel resources and ecological functions
including primary production,
provision of three dimensional habitat, biogeochemical recycling,
pollutant remediation, moderation of nutrient
pulses and population . Terrestrial and aquatic ecological
functions have been estimated to be
worth US $ 33 trillion per year globally. Freshwaters and their varied
biodiversity form part of the Earth’s
ecosphere which restores us spiritually, inspires us
aesthetically and must be passed on to future generations. The Biodiversity
Convention and the World’s Charter of Nature have emphasized
that like all other life forms, freshwater organisms
have an intrinsic right to survival and warrant respect.
Wetlands
Wetlands are transitional areas between dry terrestrial and
permanent aquatic ecosystems. These
are recognized as highly
productive ecosystems. Wetlands include 22 habitat types (IUCN, 1989). The Indian wetland area is about 7.6
million
ha, excluding paddy fields, rivers and
canals, out of which 3.6 million ha is inland
and 4 million ha coastal. There are 2,175 natural wetlands having
1.46 million ha area and 65,254 man-made lakes
having 2.85 million ha area in India .
The total number of animal species, reported from , is
89,461; out of which 17,853 belong to wetlands comprising 19.9% of the
total number. About 50,000 ha area of wetlands is degraded
every year in Asia .
It results in soil acidification, soil erosion,
loss of soil nutrients, change
in hydrology, loss of flora and fauna and disruption of delicate
ecosystem. The wetlands perform enormous
variety of functions including regulatory, carrier, production
and information functions. The regulatory functions
include storage and cycling of nutrients, human wastes and
organic wastes; groundwater recharge and discharge; control of natural
floods, erosion and salinity; water treatment, climatic
stabilization; and maintenance of ecosystem stability; integrity
of other ecosystems and biological
diversity. The carrier functions include agriculture, irrigation,
transport, energy production, tourism, recreations, human habitat and
settlements and as nursery for plant and animal
species. The production functions include
water, food, wood fuel, medicine resources, genetic resources and
raw materials for building, construction and industrial
use. The information functions include research, education,
monitoring and their role in cultural heritage. The natural
functions of the wetlands include climatic,
biodiversity, habitat, hydrological and hydraulic and water
quantity functions. Among biodiversity
functions are centers of endemism, ecosystem diversity, habitat
diversity, species and population diversity. Besides this, they provide
diverse species assemblages, highly diverse microbiological activity,
large genetic pool and link between terrestrial and aquatic ecosystems, Wetlands
are being modified or reclaimed through
out the world, their resources over exploited, and their lands
converted to other uses. Since 1900,
more than half of the world wetlands have disappeared. Water
management in wetlands has been oriented
towards the needs of people, such as
transportation, flood control, agriculture and settlement. There
are many stakeholders whose diverse interest lay claim on the wetland
function. These include direct extensive and intensive users,
exploiters who dredge sediments or exploit mineral resources,
agricultural producers who drain and
convert wetlands to
agricultural land, water abstractors who use wetland as source of
drinking or irrigation water, human settlements expansion
and indirect users who benefit from
flood control use of the wetland
. Our primary objective
should be to build capacity for wetland management. Compilation
of national wetlands database is
the first stage of a conservation strategy. All products from the natural environment
should be valued and costed according to their real costs,
including the cost of sustainable
production and environmental protection. In , efforts have been made to restore Chilka Lagoon, a coastal
wetland and along Gandak sub basin, Bhoj Wetland and other such
water bodies. However, baseline data
on the biodiversity of freshwater ecosystem, in , is meagre.
In our studies on the Lowe Lake and
Mansarovar Lake, which for a part of Bhoj Wetland, we found 93
species of phytoplankton, 53 taxa of zooplankton, 130
of periphyton, 38 of macrozoobenthos and 26 species of fish. We
found rich aquatic flora and fauna in Chambal, Kshipra
and Khan rivers .
Scattered studies are available on the biodiversity of waterbodies in India
.
However, a continuous and
comprehensive database is not
available. Compilation of a national database is the need of the
time.
Conservation Action Plan
The conservation of aquatic
biodiversity
should be done at ecosystem level. Appropriate management of wetlands
and rivers may be a proper step in
this direction. Restoration of acidified, eutrophied or weed infested lakes need
different treatments, The main problem in Indian lakes, are: siltation,
eutrophication, weed
infestation, pollution and human encroachment
for habitation, agriculture,
aquaculture and land use. The lake management
includes passive and active
actions. In passive action, minimum human interference maintains the ecosystem
in a natural way; such system
is possible in unpolluted lake. In active management, manipulation of environmental
conditions is undertaken to affect the desired change. The active
management includes soft strategies, covering water control and weed eradication,
while hard strategies include altering
of the vegetation, construction of
dikes, canals, etc. for changing the environmental conditions. An effective
lake management would include
both soft and
hard strategies. The restorative measures would include afforestation of lake basin or catchment area; shoreline stabilization and demarcation;
maintenance
of water level; restoration of eutrophied
lakes by prevention of sewage
or nutrients from point and non-point sources, biological control,
chemical control, mechanical
control, aeration and sediment
removal; restoration of lakes having aquatic weed infestation by manual,
mechanical and biological methods;
pollution control; monitoring
the water quality for various physico-chemical and biological parameters;
development of
fisheries, tourism, etc.; environmental
awareness and evaluation of restorative measures.
All
rivers, lakes, reservoirs, wetlands, etc. should be treated as integrated component of a river
basin and a mechanism for coordination
between all programmes for conservation and management should be
developed. Necessary steps are required to ensure adequate flow in rivers for maintaining
their ecological integrity, water quality and biodiversity. The abstraction
of river and surface waters for
various uses, such as, for
agriculture, domestic and industrial use should be regulated in relation
to the total flow.
The return flow of adequate quality
by recycling and reuse of wastewater should
be endured. Certain rivers may be given status of “National Heritage Rivers”.
Conservation and
restoration of floodplains and protection of upper watersheds of rives,
throughout the country, should be given priority. A network of “Protected
Areas of River Systems” may be established to conserve riverine
biodiversity. A holistic integrated
approach for conservation of rivers and other inland surface waters
should be adopted.
Conclusions:
Wetlands,
lakes and rivers are daughters of the land. Ecologically
sound and economic practices on land as well as in the water
realm, will maintain and restore aquatic ecosystems and faltering
species can be reinvigorated with them. We need suitable practices in
watersheds and waterbodies, and willingness to
share the planet’s surface
with other species.
Prof.
S.K. Kulshrestha, President ‘Academy
of Environmental
Biology’
is a former Professor of Zoology at M.V.M. Bhopal.
His current address is: 27/3 Geetanjali
Complex, Bhopal-462003,
India
E-mail:
[email protected]
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