Transcript Document

Status of water birds in the tanks
of North Bangalore
Harish R. Bhat
Centre for Ecological Sciences
Indian Institute of Science
Bangalore 560 012
Introduction:
Wetlands: lands transitional between
terrestrial and aquatic systems where the
water table is usually at or near the surface,
or the land is covered by shallow water.
Almost all tanks Bangalore are manmade,
built for the welfare of the society.
Of late, Wetlands are de-valued as
unhealthy "wastelands”!!!
Karnataka State had about 44,000 man-made wetlands
constructed over centuries beginning with the Vijayanagara
Dynasty
At present only 36,969 wetlands exist in Karnataka!
Bangalore alone in the past had 400 tanks, but now only 130
tanks are left with just 36 ‘live’ tanks…..
In the past, people sacrificed their lives for the sake of building
tanks,
But now a days many tanks are ‘sacrificed’ in the name
development
Water Birds and Wetlands
•Indicators of lively
wetland ecosystem
•Depend for food, shelter
•Aesthetic value to the
wetland
• Ecological Importance
•Haven for bird watchers
Annual Water bird survey
Annual water bird count is conducted during
5th and 26th of January
11 tanks (Ardeshanahalli, Doddatumkur, Hebbal,
Hesarghatta, Jakkur, Kolthur, Madhurekere,
Nagavara, Puttenahalli, Singanayakanahalli and
Yelahanka) situated at the North of Bangalore are
surveyed
Tank condition, other activities in the tank region,
different species of birds along with their numbers
are documented
Findings:
•Till 2004, all the 11 tanks were in better condition, with sufficient
water, fish population
•About 42 species of water birds and water dependent birds were
documented during the census
•Hesarghatta had about 2000 birds belonging to29 species, but
had noticed bird traps at the bunds!
•Hebbal and Puttenahalli had more than 400 birds belonging to 4
species respectively
•Totally about 5000 birds were documented from all the 11 tanks
•
Findings:
In 2004, due to severe drought, 7 of these tanks were in a bad
shape being totally dried up
These were used for sheep and cattle grazing, temporary vehicle
parking places!!
Dumping of debris were noticed at the tanks
Winged visitors (Painted Storks, Open-billed Storks, Spot-billed
Pelicans and other birds) were dependent on the remaining 4
(Puttenahalli, Madhurekere, Nagavara, Hebbal) tanks that had
considerable amount of water
Findings:
In 2003,Madhurekere had 190 Painted
Storks and other birds such as
Spoonbill, White Ibis, Grey Heron,
Black-winged Stilt, Sandpipers, River
Tern, Pin-tailed Duck, Spot-billed duck
But in 2004, not even an Egret or a
Pond Heron were noticed in the same
tank
Hebbal tank was as usual rich with Pintailed duck, Spot-billed duck, Common
Pochard, Garganey Teal, Sandpipers,
Black-winged Stilt, River Tern, Grey
Heron, Purple Heron, Kingfishers,
Purple Moorhen, Common Coot and
other birds
Findings:
4th June 2003
The tank was 95% dry due
to drought
Sparse water at very
small area congregated
many fishermen and
water birds competing for
fish
Many birds were found
dead at
the Hebbal tank
The death remains
unsolved though it could
be due to drought, lack of
water, food availability,
increase in temperature
and poisoning
Findings:
2005- 2006 was fair enough for the winged visitors as the tank
condition was better with sufficient water and thus getting back
most of the water birds back to the garden city
The bird survey proved rich at Puttenahalli, Madhurekere,
Hesarghatta and Hebbal tanks
But Nagavara tank, being leased (2005) to Lumbini gardens,
developed into a ‘swimming pool’ rather than a ‘live’ tank!
Hardly very few birds like Little Cormorants, Pond Herons and
Common Coots
This year yet another tank is being leased to Oberoi- Hebbal
tank!
Findings:
Traditionally community based organizations were protecting
the catchments and regular maintenance including desilting
these tanks
With low population densities and little industry, pollution was no
threat, nor had many exotic weeds been introduced
Many pressures on land have led to encroachment of tanks and
tank beds
Such kind of ongoing changes will definitely block the water
draining pathways, leading to floods
Tanks- sinks for sewage and industrial wastes
Conclusion:
Protecting of remaining tanks from being ‘sacrificed’ for
developmental purpose
Flooding will be common phenomenon as all the
catchments areas and tanks would be encroached, thus
failing water drain
War for Water could be predicted in 2025, as almost all
tanks would be sacrificed and converted landfills and
further developed
Water birds, being good indicators for best wetland
ecosystem might permanently shift their roost to other
states
Recommendation:
•Re-trace the water draining pathways, map them and provide
the lost links
•Clear the already encroached areas by providing the
alternatives and make the water draining pathways free from
disturbance
•Alternative measures to divert the inflow of effluents
•De-weeding of aquatic weeds
•Afforestation programme to be undertaken by planting native
species
•Transfer the tank rights to the local villagers, organization and
build the bridging gap between the decision makers and the
stake holders for the betterment of remaining tanks