607
found to be sensitive to the green leaf area and green leaf biomass. The vegetation
indices such as NDVI, derived from the multispectral satellite data, represent the
vegetation vigour/canopy density and thus can be used as one of the indicator for the
ecosystem health. Chellamani et al. (2014) have used NDVI, derived from SPOTVGT products, to characterize and monitor the health of Indian mangroves. Kovcas
et al. (2005 have assessed and mapped leaf area index of mangroves at the species
level using IKONOS satellite data. As leaf area index is related to canopy density
and green biomass, it can also be used as one of the indicator of the mangrove
health.
The above health models based on a single parameter such as the vegetation
vigour/canopy density (represented by NDVI) are not robust and may not work in
certain conditions, specially, when mangroves are stressed due to anthropogenic or
natural causes. On the other hand multi parametric health models, accounting for
the mangrove vigour/canopy density, the weather, hydrology, stress factors, environment etc. may be more robust. Such multi parametric ‘Mangrove health assessment model’ has been developed for the selected mangrove zones of India (Ajai
et al. 2012). This model uses a number of environmental indicators which are generated using both, satellite data and field survey/measurements. In this study, selection
of the environmental indicators and their weighting factors (for the model) was
done through brain storming discussions, organized by Space Applications Centre,
Ahmedabad, India. Experts from all over India participated in the brain storming
discussions. In addition to identifying the environmental indicators of the mangrove
habitat health, the ‘frame work’ for the model was also finalized to assess the health
and mangroves-at-Risk using remote sensing and Geographic Information System
(GIS) techniques. Based on the detailed deliberations by the experts, the environmental indicators and their relative weightages, as finalized by the experts, are given
in the Table 19.4. As the health status of mangroves is to be given in a spatial
domain, these environmental indicators (for the mangrove forest) are to be generated in the form of spatial thematic layers.
Table 19.4 Environmental
indicators and their
weightages
Sr.
No.
Parameters
Weightage
1
Canopy cover
12
2
Floral diversity
11
3
Obstruction to natural flow
10
4
Drainage density
9
5
Natural regeneration
8
6
Anthropogenic stress
7
7
Stand size/fragmentation
7
8
Change in vegetation pattern
6
9
Tree height
5
10
Defoliation
4
11
Erosion/accretion
3
12
Sedimentation pattern in water
ways
2
19 Mangrove Inventory, Monitoring, and Health Assessment
found to be sensitive to the green leaf area and green leaf biomass. The vegetation
indices such as NDVI, derived from the multispectral satellite data, represent the
vegetation vigour/canopy density and thus can be used as one of the indicator for the
ecosystem health. Chellamani et al. (2014) have used NDVI, derived from SPOTVGT products, to characterize and monitor the health of Indian mangroves. Kovcas
et al. (2005 have assessed and mapped leaf area index of mangroves at the species
level using IKONOS satellite data. As leaf area index is related to canopy density
and green biomass, it can also be used as one of the indicator of the mangrove
health.
The above health models based on a single parameter such as the vegetation
vigour/canopy density (represented by NDVI) are not robust and may not work in
certain conditions, specially, when mangroves are stressed due to anthropogenic or
natural causes. On the other hand multi parametric health models, accounting for
the mangrove vigour/canopy density, the weather, hydrology, stress factors, environment etc. may be more robust. Such multi parametric ‘Mangrove health assessment model’ has been developed for the selected mangrove zones of India (Ajai
et al. 2012). This model uses a number of environmental indicators which are generated using both, satellite data and field survey/measurements. In this study, selection
of the environmental indicators and their weighting factors (for the model) was
done through brain storming discussions, organized by Space Applications Centre,
Ahmedabad, India. Experts from all over India participated in the brain storming
discussions. In addition to identifying the environmental indicators of the mangrove
habitat health, the ‘frame work’ for the model was also finalized to assess the health
and mangroves-at-Risk using remote sensing and Geographic Information System
(GIS) techniques. Based on the detailed deliberations by the experts, the environmental indicators and their relative weightages, as finalized by the experts, are given
in the Table 19.4. As the health status of mangroves is to be given in a spatial
domain, these environmental indicators (for the mangrove forest) are to be generated in the form of spatial thematic layers.
Table 19.4 Environmental
indicators and their
weightages
Sr.
No.
Parameters
Weightage
1
Canopy cover
12
2
Floral diversity
11
3
Obstruction to natural flow
10
4
Drainage density
9
5
Natural regeneration
8
6
Anthropogenic stress
7
7
Stand size/fragmentation
7
8
Change in vegetation pattern
6
9
Tree height
5
10
Defoliation
4
11
Erosion/accretion
3
12
Sedimentation pattern in water
ways
2
19 Mangrove Inventory, Monitoring, and Health Assessment