Indian Journal Journal of ofGeo-Marine Marine Sciences Vol. 43(6), June 2014, pp. 1061-10671055-1061

Mangrove regeneration in tsunami affected area of north and south Andaman using insitu and remote sensing techniques

Sachithanandam*, Vlo2,Mageswaran, TI, Ragavan, P', Mahapatra, MI, Sridhar, RI, Ramesh, RI & Mohan, P.M2

'Integrated Island Management Division, National Centre for Sustainable Coastal Management, Ministry of Environment and Forest, Koodal Building, Anna University Campus, Chennai-600 025,

2Department of Ocean Studies and Marine Biology, Pondicherry University, Brookshabad Campus, Post Bag No.OI, -744 112, Andaman and Nicobar Islands, India

[*E-mail: [email protected]]

Received 17December 2012; revised 2 May 2014

Present study assessed the area of mangroves regeneration and rejuvenation status at North and South Andaman, 5 years later to Tsunami occured in 2004. Trees, Saplings and Seedlings were identified and collected during the traverse in this transect and enumerated all species of mangrove. GARMIN GPS was used to record sampling location and data collection points. Regeneration of mangrove trees after the devastation of tsunami has also been identified using Remote Sensing techniques and field observations. Submergence and degradation takes place in the seaward mangroves and the landward or riverine mangroves subsequently. Present study infers that the tsunami affected Island environment requires minimum five years for the regeneration of the dead mangroves after the catastrophic event.

[Keywords: Mangrove, Regeneration, GIS, Tsunami]

Introduction about one fifth of the country's extensive and diverse mangroves, next only to Sundarbans and Gujarat. Indian mangrove habitats are situated in three About 966 sq. Ian of these islands are covered by zones: (i) East Coast, about 4700 knr', (ii) West Coast, biologically diverse mangroves or in other words, the about 850 km', and (iii) Andaman and Nicobar Islands mangroves constitute 10.85% of the total forest area including Lakshadweep atoll consists of about 1190 7 Sq.km'. Ninety species of mangrove exists in the of these islands. According to Sidhu , mangrove forest world's coastline? and in India 62 species are reported of Andaman and Nicobar Islands constitute approximately 17% of the total mangrove area of till date3• These 62 species of mangroves are distributed in 52 genera and 36 families from all the India. 55 mangrove species belonging to 22 genera 12 habitats in India". East coast ofIndia has larger and 18 families of mangroves are known from the (about 80%) mangrove areas than the west coast , in which India covered 39 species of (20%) due to gradual slope as well as the deltas of mangroves", A total of34 exclusive mangrove species major rivers'. among 17 genera and 13 families was recorded from the Andaman and Nicobar Islands". The consists of North-South oriented, crescent shaped group of Islands called the The 2,260 km of Indian coastal zone harbour Andaman and Nicobar Islands and are one of the many key marine ecosystems 10. However, after the largest archipelago system (6°45' and 13°41' north Tsunami, the whole scenario had been changed, i.e. latitude and 92°]2' and 92°57' east longitude) in the tide level had increased one meter, which lead to world". It consists of about 572 islands, rocky outcrops inundation of mangroves under seawater I I. According and islets. The coastlines of Andaman endowed with to the latest estimate of the Forest Survey of India', 10621056 INDIAN J MAR SCI V OL 43 (6), JUNE 2014

To identify the mangroves distribution, degradation and rejuvenation in the tsunami affected areas, a belt transect was laid perpendicular to the shoreline. Samples were collected identified. GPS was also used for the positioning of the data collection points. The length of transect depends on the vegetation cover, i.e. in some places vegetation was found dense and in some places it was sparse. In the plotted line counting of the species was executed by categorization. GIS and Remote Sensing Approaches Remote Sensing technique was used to determine the changes in the mangroves using IRS LISS III of 2003 and 2009. Remote sensing images of IRS P6 LISS III 2003 & 2009 data was used to map the mangroves. IRS P6 LISS III provides data in 4 spectral bands; green, red, Near Infra Red (NIR) and Short Wave Infra-Red (SWIR), with 23.5 m spatial resolution and 24 days repeat cycle. Spatial resolution is suitable for mangrove mapping and landuse/land cover changes which is obtained from National Fig. 1–Study Area Remote Sensing Centre (NRSC). In addition to that the total area under mangrove cover in India is 4663 km2, Survey of India toposheet was also used for the study. 617 km2 of which (13% of the total mangrove area of the Indian Territory) occurs in the ANI5,12. In Andaman district, the area under mangroves is 614 km2. Area under mangrove cover has decreased significantly during the last decade5,12 possibly leading to change in floristic composition and local extinction of some species. According to FSI5, 12 about 43 km2 of mangrove cover decreased between 2003 and 2007 in the ANI. Present work designed to assess and detect mangrove ecosystems status after five year of devasting tsunami occurrence, what extend the mangroves are regenerated and also to understand the natural revival of these environments for futuristic coastal management. Materials and Method In the current study Flat Bay - Port Blair (South Andaman) and Arial Bay - Diglipur (North Andaman) were chosen because the tectonic activity occurred during 2004 submerged south Andaman and 1.5 m Fig. 2–Flow chart Methodology adopted for identifying for uplift of North Andaman13. Mangrove vegetation SACHITHANANDAM et al: MANGROVE REGENERATION IN TSUNAMI AFFECTED AREA ‘ 10631057

The pre-processing techniques such as radiometric in the landward side. The mangrove degradation was and geometric corrections were carried out. Then, the very high in North Andaman when compared to the satellite images were rectified using ground controlled south Andaman study area (Fig. 3&4). points (GCP) obtained from the field using Garmin GPS. ERDAS IMAGINE software (version 13.0) software was used to rectify the satellite data. The geo-referenced image was undergone spatial enhancement for the better clarity of the image features. Image processing methods such as NDVI, unsupervised, supervised classification, Band ratio/ PCA techniques were used to clearly identify the mangroves. Finally, the mangrove map of 2003 and 2009 was generated using Arc GIS and area was calculated as shown in the figure. The details of approach and methodology used were shown in the flow chart (Fig. 2). Mangrove community structure analysis:

Species distribution and richness comparison Fig. 3–Species compostion at Areial Bay North Andaman study for these sites were carried out using PRIMER 6.02 version14 software (Plymouth Routines in Multivariate Ecological Research, Plymouth, UK) to understand the extent two samples were shared for particular species at comparable levels of abundances (Bray-Curtis similarity). Species richness and diversity also calculated using the Simpson and Shannon index. Results It was observed that large amount of mangroves were degraded around Port Blair of about 135.27 ha and 53 ha in North Andaman- Aerial bay. The Sippighat region of South Andaman is low lying which was severely affected by the tsunami waves Fig. 4–Species compostion at Flat bay South Andama and only 7.5 ha of mangroves was recovered with decreased and scattered biomass. Other areas like Mangrove and other associated species at North Bamboo flat, Minnie Bay where tsunami inundation and South Andaman Tsunami affected area were had been noticed but no significant impact on represented by four dominant taxa, i.e. Acanthus spp., mangroves. Among the four locations Sippighat was Avicenna spp., Rhizophora spp., Bruguiera spp. worst affected due to tsunami event followed by Ceriops spp. and Xylocarpus spp. and least species Bamboo flat, Minnie Bay and Aerial bay. However, diversity noticed by Nypa fruticans, Acrostichum rejuvenation of mangroves was observed in the aureum, Excoecaria agallocha, Lumnitzera tsunami affected areas during the field visit during racemosa, Excoecaria agallocha, Heritiera littoralis, the month of May 2009. Rejuvenation in the Bamboo Lumnitzera racemosa, Phoneix paludosa and flat region about 3 ha and the mangrove saplings were Sonneratia alba (Table.1). 10581064 INDIAN J MAR SCI V OL 43 (6), JUNE 2014

The species composition at North Andaman Discussion (Ferial Bay) shows that Ceriops spp. – 22%; Southern part of south Andaman consists of 3000 Rhizophora spp., 20%; Bruguiera spp. – 11%; ha mangrove forest which comprises about 9.7% of Xylocarpus spp. – 11% and mangrove associated total forest of South Andaman15. These mangrove species – 14% and dead trees around 22% (Fig.3) the species are mostly distributed on narrow patches on South Andaman showed site species composition the sheltered coastal areas16. After tsunami, mangrove (Fig.4) that Rhizophora spp., - 34%; Ceriops spp. – ecosystems damaged severely and latter it was 23%; Bruguiera spp. – 16%; Xylocarpus spp. – 11% recruited and developed to different stages. The and mangrove associated species – 12% and dead regeneration term has been mentioned to the damaged trees around 4%. trees or seedlings which started to grow again.

Table 1–List of Mangrove Species Identified in Study Area

Sl. No. North Andaman South Andaman

1 Acanthus ilicifolius L. Aegiceras corniculatum (L.)Blanco 2 Acrostichum aureum L. Acanthus ebracteatusVahl

3 Aegiceras corniculatum (L.)Blanco Acanthus ilicifolius L.

4 Avicennia marina (Forsk.)Vierh. Acrostichum aureum L. 5 Avicennia officinalis L. Avicennia marina (Forsk.)Vierh.

6 Bruguiera cylindrica (L.) Bl. Bruguiera cylindrica (L.) Bl.

7 Bruguiera gymnorrhiza (L.) Savigny Bruguiera gymnorrhiza (L.) Savigny 8 Bruguiera parviflora (Roxb.)W. A. ex Griff. Bruguiera parviflora (Roxb.)W. A. ex Griff.

9 Ceriops tagal (Perr.) C.B. Rob. Ceriops tagal (Perr.) C.B. Rob.

10 Cynometra iripa Kostel Dolichandrone spathacea (L.f)Schum. 11 Excoecaria agallocha L. Excoecaria agallocha L.

12 Heritiera littoralis Dryn. Lumnitzera littorea (Jack.)Voigt.

13 Lumnitzera littorea (Jack.)Voigt. Nypa fruticans Wurmb. 14 Phoenix paludosa Roxb. Phoenix paludosa Roxb.

15 Rhizophora mucronata Poir. Rhizophora mucronata Poir.

16 Rhizophora apiculata Bl. Rhizophora apiculata Bl. 17 Scyphiphora hydrophyllacea Gaertn.f. Scyphiphora hydrophyllacea Gaertn.f.

18 Sonneratia alba J. Smith Sonneratia alba J. Smith

19 Xylocarpus granatum Koen Xylocarpus granatum Koen 20 Xylocarpus mekongensis (Prain) Pierre Xylocarpus moluccensis (Lamk.) Roem SACHITHANANDAM et al: MANGROVE REGENERATION IN TSUNAMI AFFECTED AREA ‘ 10651059

Fig. 6a–Pre Tsunami inundation in Aerial Bay (North Fig. 5a–Pre Tsunami inundation in Flat Bay (South Andaman) - 2003 Andaman) – 2003

Fig. 5b–Post Tsunami inundation in Flat Bay (South Andaman) – 2009

The present work of Flat Bay exhibited all the stages of Avicennia marina which is a similar pattern described by Dam Roy and Krishnan17. This suggested that after tsunami the Avicennia marina Fig. 6b–Post Tsunami inundation in Aerial Bay (North acclimatized the present environment. But in Minnie Andaman) - 2009 10601066 INDIAN J MAR SCI V OL 43 (6), JUNE 2014

Bay stations even though fully grown stage of Conclusion Avicennia marina is absent, the other developmental Mangrove is bio-shield and ecological sensitive stages are available due its quick acclimatization to of marine animals20 nutrient recycling and this environment, which also support the above biogeochemical process21 section of tidal gradients inference. Further, Sippighat have not reached the and elevation22-23. Present study of sample delineation, suitable environment for the development of species regeneration, sapling and seeding records Avicennia marina. However, Rhizophora apiculata based on the ground data is invaluable for appropriate and Rhizophora mucronata growth noticed in the management (plantation) and conservation of south Sippighat stations suggested that the present Andaman mangrove area. Based on the results environment suitable for development of these obtained from the analysis of satellite data of IRS-P6 species. This is further supported by absence of LISS III. 2003 and 2009 imageries it has been saplings in all stations of these two species and concluded that there are large amount of mangroves availability of seedlings suggested that minimum five were affected in South Andaman when compared to years are needed to convert the Tsunami affected area the North Andaman. Sippighat encountered the to normal condition of their development. maximum inundation due to tsunami event whereas other study sites, the inundation was noticed but not From the satellite data analyzed for pre and post significant to destroy the mangrove vegetation. tsunami, identified that totally 135.27 ha of Acknowledgements mangroves has decreased in the study area of South Andaman and 52.75 ha of North Andaman. The same The first author thanks the Ministry of Earth pattern was also studied in by Sciences, (Geo-Trace projects) New Delhi for funding Saravanan et al.18. He observed that the tsunami waves this work. Authors acknowledge the Vice-Chancellor drastically affected the plantation of about 38.94 ha of Pondicherry University to provide the facilities to and mangrove 194.53 ha. The Past Tsunami status of execute this project. Authours express sincere thanks mangroves of Little Andaman showed that around to Dr. K. Dharanirajan and Mr. E. Yuvaraj Department 3400 ha mangroves was submerged, around 1700 ha of Disaster Managements Pondicherry University, for their great helpful for GIS data support and analysis was damaged, around 140 ha was degraded (Shankar for this study. et al. (2009) using remote sensing technology. Additionally, Flat Bay coast were also studied where References mangroves are existed above 23% of total mangrove 1. Mandal, R.N & Naskar, K.R., Diversity and classification forest of South Andaman decreased19. of Indian mangroves: a review. Tropical Ecology, 49 (2008) 131-146. The southern part of the Andaman Islands have 2. Tomlinson, P.B., The Botany of Mangroves. Cambridge suffered greater casualties. The mortality of the University Press, (1995), pp. 1- 413. mangroves is mainly due to low respiration as a result of burying pneumatophores. Although mangroves 3. Kathiresan, K & Bingham, B.L. Biology of mangroves and mangrove ecosystems. Advances in marine biology, remain in waterlogged conditions, the nonexposure 40 (2001) 84-254. of the breathing roots for six–eight hours a day has 4. Kathiresan, K., Importance of mangrove forest. Journal 10 leads to the mortality of the mangroves . In Nicobar of Costal environment, 1 (2011)11-26. group of islands mangrove affected area in different 5. FSI., India State of Forest Report 2011. Forest Survey of islands such as Camorta Island 51%, Katchal Islands India, Ministry of Environment & Forests, Government 69%, Nancowry islands 100% and Trinket Islands of India publication, Dehradun (India) 2011. 68% of mangrove vegetation smashed by Tsunami 6. Sachithanandam, V., Mohan, PM., Muruganandam, N., waves13. Chaaithanya, I.K., Dhivya, P. & Baskaran, R., DNA SACHITHANANDAM et al: MANGROVE REGENERATION IN TSUNAMI AFFECTED AREA ‘ 10671061

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