Identifying Information Gaps to Assess Bio-physical Underpinning for Mangrove Resilience and Coastal Sustainability

Presented at International Conference on Mangroves for Sustainability, Colombo, Sri Lanka on 22-24 July 2024.

1. Presented by : SamakshiTiwari, Research Fellow
Affiliation : Mangrove Monitoring for Climate Change Mitigation, Centre for International Forestry
Research & World Agroforestry (CIFOR –ICRAF)
Country : India
Authors : S. Tiwari, S. Debnath, S. Sharma, R. MacKenzie, R. K. Bhomia
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Identifying Information Gaps to Assess Bio-physical
Underpinning for Mangrove Resilience and Coastal
Sustainability
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2. Mangroves
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Benefits
Mangroves
provide many
ecosystem
services.
Protect
against
cyclones and
floods.
Help purify
water.
Provide
fodder, fish &
other marine
catch.
Concerns
Cover < 1 % of
global land area.
Mangrove area
decreased by 1.04
Mha between 1990
- 2020.
Climate change:
Increased
frequency of
Cyclones & floods.
Sea Level Rise.
Deforestation, salinity
change, pollution &
reduction in sediment
& freshwater flows.
Source: www.carbonbrief.org

3. Conserving Mangroves
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Understand reasons for mangrove
decline.
Restoration and plantation – site
specific guidelines.
Adequate management with local
information e.g.- desilting of creeks.
Using scientific techniques to understand
processes underlying mangrove’s
resilience.

4. Objectives
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Develop
A framework for a
regional monitoring
network in South and
Southeast Asia.
Evaluate
Countries for expanding
& improving long-term
monitoring sites,
considering mangrove
coverage, decline, &
restoration potential.
Elaborate
Challenges in
developing the
network, using India
as a case study.

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Monitoring Methods
Buried plates and sediment traps-do not give information on
land subsidence and can get affected by rain.
Remote sensing- often not supported by on-ground data.
Studies may by conducted in isolation.
Long-term monitoring is difficult.

6. Addressing Knowledge Gaps
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Using Rod Surface Elevation Tables (rSETs) as long-term
monitoring sites to determine sediment dynamics.
Understanding sedimentation data in conjunction with
salinity and tidal changes, and land subsidence.
Designing adaptive management strategies leading to
effective restoration and conservation.
Salinity Sensor
Water Depth Sensor
rSET

7. Methodology
Study Area : South and Southeast Asia
•Importance metric : Based on existing mangrove
area for a country and its contribution to coastal
sustainability.
•Urgency : Based on the loss of mangrove area.
•Utility : Based on restorable areas to support
successful restoration.
•Existing rSETs across Asia
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8. Results
rSETs have been
installed in 8 out
of 15 mangrove
countries in the
region.
A total of 141
long-term
monitoring
stations.
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Red List Category: IUCN, 2024
Bunting et al.,2022

9. 1866
436
168 156 175
0
1000
2000
3000
4000
5000
6000
0
1000
2000
3000
4000
5000
6000
IndonesiaMyanmarMalaysiaPhilippinesThailand
Restorable Potential (Km
2
)
Mangrove Cover (Km
2
)
Mangrove Cover (km
2
) 2020 and Restorable
Potential (km
2
) 2016
Mangrove
cover
Restorable
Potential
Southeast Asia
•Myanmar and Malaysia need long-
term monitoring most urgently.
•Borneo Island in the Sunda Shelf is
currently not monitored.
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0
2
4
6
8
10
12
14
SingaporeMyanmarIndonesiaVietnam
Mangrove Loss (%)
Loss since 1996 (%)
30,000

10. Philippines: Effective Understanding of
Mangrove Resilience Using Long-term
Monitoring.
rSETs contribute to understanding that natural sites in
protected area of Quezon province are threatened to
drown due to sea level rise.
Whereas restored sites are more resilient to sea level
rise.
12 rSETs
First measurement : 2015
Duration : 3 years
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Castillo, J.A.; MacKenzie, R.; Manahan, J.R.; Castillo, J. Monitoring the Sediment Surface Elevation Change across a
Chronosequence of Restored Stands of Tropical Mangroves and Their Contemporary Carbon Sequestration in Soil
Pool. Forests 2022, 13, 241. https://doi.org/10.3390/f13020241

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rSET based
monitoring required :
Sri Lanka : 25 %
mangrove lost
since1996.
Pakistan : 20 %
mangrove lost
since1996.
South Asia
138 152
34 29
0
100
200
300
400
500
600
700
800
900
0
100
200
300
400
500
600
700
800
900
Bangladesh India Pakistan Sri Lanka
Restorable Potential (km
2
)
Mangrove Cover (km
2
)
Mangrove Cover 2020 (km
2
) 2020 and
Restorable Potential (km
2
) 2016
Mangrove cover
Restorable Potential
Bangladesh: Sundarbans mangrove has sedimentation rate exceeding relative sea level
rise (Bomer et al. 2020).
4500 4000

12. South Asia : India
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Long – term monitoring started in 2020.
47 rSETs
•17 in Andaman Islands
•10 in Coringa Wildlife Sanctuary, Andhra Pradesh
•20 in Sundarbans, West Bengal
44 automated water level & salinity sensors
•20 in Andaman Islands
•11 in Coringa Wildlife Sanctuary, Andhra Pradesh
•13 in Sundarbans, West Bengal
Characterization of mangrove vegetation and
carbon stocks to understand climate change
mitigation potential.

13. Constraints
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Difficult terrain Wildlife Tidal changes
Restrictive
access
Funds
Technical
capacity

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•Has 39% global mangrove cover but has lost
2725.19 km
2
(4.5 %) since 1996.
•Much higher sea level rise (4mm/yr).
Relevance and Importance of Monitoring in
South and Southeast Asia
•Predominantly
developing
countries with high
pressure on
mangroves.

15. Take Home Message
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•Long-term monitoring of mangroves has started but needs to be
expanded.
•Sediment dynamics (rSETs) will benefit from concomitant
understanding of tidal and salinity changes.
•Initially challenging to establish, but long-term monitoring sites
provide useful information for coastal sustainability.

16. Acknowledgements
Financial support: USDA Forest Service and USAID.
Collaborating Institutes: M. S. Swaminathan Research Foundation,
Indian Institute of Science Education and Research, Kolkata,
Wildlife Institute of India and Vidyasagar University.
Government Institutes: National Centre for Coastal Research,
Andhra Pradesh Forest Department, West Bengal Forest
Department and Andaman and Nicobar Forest Department.
Local community members as boat staff and field assistants.
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Images: CIFOR-ICRAF

17. Mail: [email protected]
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https://www.cifor-icraf.org/mangrove-monitoring-
india/
For more information related to Mangrove
Monitoring in India Program:
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