This document summarizes a case study examining the influence of urbanization on wetlands in Bangalore, India using amphibians. It finds that as the distance from urban centers increases, species richness and green coverage increases, while factors like proximity to asphalted roads, pollution levels, and population density decrease. Over 300 lakes existed in Bangalore historically, but many have been lost, degraded, or converted to other land uses as urbanization increased. Remaining wetlands face threats from encroachment, sewage discharge, sand mining, and lack of connectivity. The study concludes wetlands need to be managed holistically rather than developed, and their beneficial ecological functions of absorbing water, storing it, and gradual release need protecting to

1. Influence of Urban-Rural Gradient on
Wetlands of Bangalore:
A case study using amphibians
Gururaja KV
CiSTUP, IISc, Bangalore
Email: gururaj@cistup.iisc.ernet.in

2. Water bodies in Bangalore
• Vrishabhavathi, Challaghatta and
Hebbal Group Species
• # > 300, hundred year back, almost Butterflies 154
all man made; as of today 81 with
water (except a few, all polluted) Fishes 41
• 28 lakes officially converted to bus
stand, sports Frogs 18
complex, residential/commercial
complex Reptiles 37
• 7 lakes cannot be traced! 18 an- Birds 395
authorized urban poor dwelling, 14
dried up Mammals 41
• 12 lakes given to BDA for
restoration! Plants >500
• Encroachment, sewage, industrial
discharge, sand mining!
Source: Karthikeyan (1999)+BNG Birds
Personal obsevations

3. Why Amphibians?
• Greek, Amphi – dual; bios
– life, two life stages
• Tadpole stage, generally in
water
• Adult stage, either water
or land
• Ectotherms, Skin
breathers, Anamniotes
• Best bio-pest controllers
– Algaecide, larvicide
• Human welfare: AMPs
• Cultural Issues
– Rig veda;
– Association with rain

4. Variables used
Water bodies Distance Pollution Road Green Connectivity Area Pop.Density
(km) (km) (%) (ha) (ind/sq.km)
Bannerghatta 23.16 No 0 100 Yes 2 1025.9
Doddannekundi 10.32 Yes 0.72 25 No 47.08 1816.5
Hebbala 7.27 Yes 2.05 37 Yes 64.5 5678.48
IISc 5.23 No 0 100 No <1 4069.21
Kommaghatta 14.28 No 1.47 87 Yes 15 2279.37
Konsandra 14.85 No 0.26 100 Yes 11.41 2279.37
Lalbagh 3.54 Yes 0.18 75 No 12.9 14590.69
Madivala 8.04 Yes 2.51 0 No 114.16 5308.96
Malathalli 10.23 No 0 87 Yes 3 2554.29
Mattikere 7.2 Yes 0.85 0 No 39.34 19109.27
Puttenahalli 14.63 Yes 0.31 50 Yes 8.87 3097.17
Rachenahalli 10.04 No 0.76 50 Yes 60 2046.34
Ramasandra 14.61 No 0.62 100 Yes 30 2279.37
Sankey 3.52 Yes 1.15 50 No 10 4069.21
Sompura 15 No 0.23 100 Yes 3.07 850.33
Thalaghattapura 13.8 No 0.04 75 Yes 3 850.33
Tindlu 10.02 No 0.53 38 Yes 46.44 5152.38
Ullalu 11.85 No 0 100 Yes 4 2279.37
Ulsoor 2.62 Yes 3 0 No 35.81 21363.69
Varthur 17.24 Yes 1.41 50 Yes 180.4 929.1
Vengaiah Kere 12.3 Yes 1.01 13 No 21.78 4977.54
Venkateshpura 11.39 No 0 87 Yes 2.8 874.96
1

5. Amphibian density and diversity
Eup_cya Mic_ orn Fej_cap Pol_ mac Dut_mel Fej sp. Hop_tig Ram_var Kal_tap
Bannerghatta 8 6 3 2 3 1 1 1
Doddannekundi
Hebbala 3 2 1
IISc 2 2 2 1
Kommaghatta 2
Konsandra 2 1 1
Lalbagh
Madivala 1 1
Malathalli 2
Mattikere 1
Puttenahalli 4 3 2
Rachenahalli 2 2 2
Ramasandra 1 1 1 1 1
Sankey
Sompura 2 1
Thalaghattapura 1 1 1
Tindlu 4 3 2 1
Ullalu 2 2 2 1
Ulsoor
Varthur 3 1 2 1
Vengaiah Kere 1
Venkateshpura 4 1 1 1

6. Distance from water body
1
Species Min (m) Max (m) n
Euphlyctis cyanophlyctis 0.5 5.0 10
Microhyla ornata 0.5 5.0 10
Fejervarya caperata 0.5 5.0 10
Polypedates maculatus 1.0 100.0 5
Duttaphrynus melanostictus 0.5 150.0 4
Fejervarya sp 0.5 10.0 10
Hoplobatrachus tigerinus 2.0 75.0 4
Ramanella variegata 3.0 15.0 2
Kalaoula pulchra 1.5 60.0 6

7. Non-metric multidimensional Scaling
Asphalted road, Pollution, Pop.density
50m
Wetland
Terrestrial buffer
0.16
Malathalli Sompura
Lalbagh
Talaghatta Aquatic buffer
0.12
0.08
Sankey Kommaghatta Venkateshpura_
Konasandra IISc
0.04
Coordinate 2
Doddannekundi Ullalu
-0.4 -0.32 -0.24 -0.16 -0.08 0.08 0.16 0.24 0.32
Ramasandra
Ulsoor Vengaiah_Kere Rachenahalli
-0.04
Mattikere
-0.08
Puttenahalli
Madivala
-0.12
Bannerghatta
-0.16 Varthur
Hebbala Tindlu
-0.2
Coordinate 1
Distance from city centre, species richness, Green cover

8. Findings
• Water bodies are not ‘tea cups’
– Drain, dredge, develop will not work
– With pavements all around, percolation gets reduced
– Reduced green cover, reduces receiving capacity and
increases run off
– Toxic run off directly gets into water
• Water bodies are not sewers: Three important things
they do - Receive, Store and Release
• Beneficial to individuals to entire city!

9. Future directions
• Managerial question: How to do it?
– Ecological underpinnings in development and design
– One reporting agency, many collaborating agencies
– On priority – work on peripheral water bodies
– Treat individual water body based on its
environmental history
– Local community involvement
– Legislation
– Understanding Synurbanization
– Urban dynamics (temporal changes)

10. Thank you