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First report on the distribution of Aegiceras corniculatum (L.) Blanco (Primulaceae) from the Nicobar archipelago, India

Abstract

The 2004 Sumatra-Andaman earthquake (9.3 Mw) and subsequent tsunami caused upliftment and subsidence throughout the Andaman and Nicobar archipelago. This incident has significantly impacted the mangroves (97% vegetation loss) and coastal ecosystems of the Nicobar archipelago. Interestingly, the coastal subsidence has also created new intertidal habitats in the erstwhile agricultural lands and terrestrial forests, which provided an opportunity for the colonization of mangrove species. During our long-term monitoring of mangrove colonization in the Nicobar archipelago, we collected Aegiceras corniculatum (L.) Blanco (Primulaceae) from Alreak, in Nicobar Islands. The occurrence of this species forms a new distributional record for the Nicobar archipelago. The present article provides detailed information on its taxonomy, ecology, and discusses the potential future spread of this species in the Nicobar Islands.

Keywords
2004 Tsunami; Coastal Subsidence; Mangrove colonization; New intertidal habitats; Southeast Asia

Natural disturbances and geological processes play a critical role in shaping species distribution patterns and composition of ecological communities ( White, 1979White, P. S. 1979. Pattern, process, and natural disturbance in vegetation. The Botanical Review, 45(3), 229–299. DOI: https://doi.org/10.1007/bf02860857
https://doi.org/10.1007/bf02860857...
; Alongi, 2008Alongi, D. M. 2008. Mangrove forests: Resilience, protection from tsunamis, and responses to global climate change. Estuarine, Coastal and Shelf Science, 76(1), 1–13. DOI: https://doi.org/10.1016/j.ecss.2007.08.024
https://doi.org/10.1016/j.ecss.2007.08.0...
; Krauss and Osland, 2020Krauss, K. W. & Osland, M. J. 2020. Tropical cyclones and the organization of mangrove forests: a review. Annals of Botany. DOI: https://doi.org/10.1093/aob/mcz161
https://doi.org/10.1093/aob/mcz161...
). Especially, the high-intensity large-scale disturbances can result in the colonization of species that are distinct from the species that previously occupied the landscape ( Platt and Connell, 2003Platt, W. J. & Connell, J. H. 2003. Natural Disturbances and Directional Replacement of Species. Ecological Monographs, 73(4), 507–522.; Nehru and Balasubramanian, 2018Nehru, P. & Balasubramanian, P. 2018. Mangrove species diversity and composition in the successional habitats of Nicobar Islands, India: A post-tsunami and subsidence scenario. Forest Ecology and Management, 427, 70–77. DOI: https://doi.org/10.1016/j.foreco.2018.05.063
https://doi.org/10.1016/j.foreco.2018.05...
). The 2004 Indian Ocean tsunami and the geo-morphological changes due to tectonic subsidence have created two opposite ecological scenario in the Nicobar Islands. Firstly, the catastrophe has degraded 97% of Nicobar’s mangrove cover, and secondly, the coastal subsidence has formed new intertidal habitat for mangrove colonization ( Nehru and Balasubramanian, 2018Nehru, P. & Balasubramanian, P. 2018. Mangrove species diversity and composition in the successional habitats of Nicobar Islands, India: A post-tsunami and subsidence scenario. Forest Ecology and Management, 427, 70–77. DOI: https://doi.org/10.1016/j.foreco.2018.05.063
https://doi.org/10.1016/j.foreco.2018.05...
). While the mangroves are reconciling post disturbance, the disturbance event has drastically altered the mangroves’ species assemblage ( Nehru and Balasubramanian, 2018Nehru, P. & Balasubramanian, P. 2018. Mangrove species diversity and composition in the successional habitats of Nicobar Islands, India: A post-tsunami and subsidence scenario. Forest Ecology and Management, 427, 70–77. DOI: https://doi.org/10.1016/j.foreco.2018.05.063
https://doi.org/10.1016/j.foreco.2018.05...
), and provided an opportunity for the colonization of mangrove species that were earlier unreported in this archipelago ( Thirumurugan et al., 2022Thirumurugan, V., Singh, A. R. & Prabakaran, N. 2022. First report on the occurrence of Avicennia marina (Forssk.) Vierh. (Acanthaceae) in the Nicobar archipelago. Ocean and Coastal Research, 70. DOI: https://doi.org/10.1590/2675-2824070.21077vt
https://doi.org/10.1590/2675-2824070.210...
).

The post tsunami studies have documented a slightly higher mangrove species richness (n=24 species) (Nehru and Balasubramanian, 2011Nehru, P. & Balasubramanian, P. 2011. Re-colonizing mangrove species in tsunami devastated habitats at Nicobar Islands, India. Check List, 7(3), 253–256. DOI: https://doi.org/10.15560/7.3.253
https://doi.org/10.15560/7.3.253...
, 2018Nehru, P. & Balasubramanian, P. 2018. Mangrove species diversity and composition in the successional habitats of Nicobar Islands, India: A post-tsunami and subsidence scenario. Forest Ecology and Management, 427, 70–77. DOI: https://doi.org/10.1016/j.foreco.2018.05.063
https://doi.org/10.1016/j.foreco.2018.05...
; Goutham-Bharathi et al., 2014Goutham-Bharathi, M., Roy, S., Krishnan, P., Kaliyamoorthy, M. & Immanuel, T. 2014. Species diversity and distribution of mangroves in Andaman and Nicobar Islands, India. Botanica Marina, 57(6), 421–432. DOI: https://doi.org/10.1515/bot-2014-0033
https://doi.org/10.1515/bot-2014-0033...
; Ragavan et al., 2015Ragavan, P., Saxena, A., Mohan, P. M., Ravichandran, K., Jayaraj, R. S. C. & Saravanan, S. 2015. Diversity, distribution and vegetative structure of mangroves of the Andaman and Nicobar Islands, India. Journal of Coastal Conservation, 19(4), 417–443. DOI: https://doi.org/10.1007/s11852-015-0398-4
https://doi.org/10.1007/s11852-015-0398-...
; Thirumurugan et al., 2022Thirumurugan, V., Singh, A. R. & Prabakaran, N. 2022. First report on the occurrence of Avicennia marina (Forssk.) Vierh. (Acanthaceae) in the Nicobar archipelago. Ocean and Coastal Research, 70. DOI: https://doi.org/10.1590/2675-2824070.21077vt
https://doi.org/10.1590/2675-2824070.210...
), compared to the pre-tsunami studies (n=23 species) in the Nicobar archipelago ( Thothathri et al., 1973Thothathri, K., Banerjee, S. P., Mukherjee, P. K., Hajra, P. K. & Pal, G. D. 1973. Botanical Results of the Joint Scientific Expedition to the Great Nicobar Island. Nelumbo, 15(3–4), 235–265.; Gopinathan and Rajagopalan, 1983Gopinathan, C. P. & Rajagopalan, M. S. 1983. Mangrove resources. CMFRI Bulletin, 34, 44–46.; Chakrabarthy, 1985Chakrabarthy, T. 1985. Excoecaria indica (Euphorbiaceae) on Great Nicobar Island. Journal of Economic and Taxonomic Botany, 6, 438.; Dagar et al., 1991Dagar, J. C., Mongia, A. D. & Bandyopadhyay, A. K. 1991. Mangroves of Andaman and Nicobar Islands. Oxford: Oxford & IBH Pub. Co., 1993Dagar, J. C., Singh, N. T. & Mongia, A. D. 1993. Characteristics of mangrove soils and vegetation of Bay Islands in India. In: Towards the rational use of high salinity tolerant plants (pp. 59–80). Springer Netherlands. DOI: https://doi.org/10.1007/978-94-011-1858-3_6
https://doi.org/10.1007/978-94-011-1858-...
; Jagtap, 1992Jagtap, T. G. 1992. Marine flora of Nicobar group of islands in Andaman Sea. Indian Journal of Marine Sciences, 21(1), 56–58.; Sinha, 1999Sinha, B. K. 1999. Flora of Great Nicobar Island. Dehra Dun: Botanical Survey of India.) ( Table 1). Meanwhile, five species that were reported to be common in the archipelago were expectedly become locally extinct after the 2004 tsunami due to habitat loss ( Prabakaran, 2020Prabakaran, N. 2020. Mangrove community response to subsidence inflicted sea level change in Car Nicobar Island, India. Botanica Marina, 63(5), 419–427. DOI: https://doi.org/10.1515/bot-2019-0088
https://doi.org/10.1515/bot-2019-0088...
; Thirumurugan et al., 2022Thirumurugan, V., Singh, A. R. & Prabakaran, N. 2022. First report on the occurrence of Avicennia marina (Forssk.) Vierh. (Acanthaceae) in the Nicobar archipelago. Ocean and Coastal Research, 70. DOI: https://doi.org/10.1590/2675-2824070.21077vt
https://doi.org/10.1590/2675-2824070.210...
). Moreover, most of the post tsunami studies have reported species without proper authentication, such as the collection of herbarium specimens and description of distribution and ecology. Meanwhile, Sonneratia ovata Backer ( Nehru and Balasubramanian, 2012Nehru, P. & Balasubramanian, P. 2012. Sonneratia ovata Backer (Lythraceae): status and distribution of a near threatened mangrove species in tsunami impacted mangrove habitats of Nicobar Islands, India. Journal of Threatened Taxa, 4(15), 3395–3400. DOI: https://doi.org/10.11609/jott.o3009.3395-400
https://doi.org/10.11609/jott.o3009.3395...
), Sonneratia lanceolata Blume, Schypiphora ( Ragavan et al., 2015Ragavan, P., Saxena, A., Mohan, P. M., Ravichandran, K., Jayaraj, R. S. C. & Saravanan, S. 2015. Diversity, distribution and vegetative structure of mangroves of the Andaman and Nicobar Islands, India. Journal of Coastal Conservation, 19(4), 417–443. DOI: https://doi.org/10.1007/s11852-015-0398-4
https://doi.org/10.1007/s11852-015-0398-...
; Nehru and Balasubramanian, 2018Nehru, P. & Balasubramanian, P. 2018. Mangrove species diversity and composition in the successional habitats of Nicobar Islands, India: A post-tsunami and subsidence scenario. Forest Ecology and Management, 427, 70–77. DOI: https://doi.org/10.1016/j.foreco.2018.05.063
https://doi.org/10.1016/j.foreco.2018.05...
), and Avicennia marina (Forssk.) Vierh ( Thirumurugan et al., 2022Thirumurugan, V., Singh, A. R. & Prabakaran, N. 2022. First report on the occurrence of Avicennia marina (Forssk.) Vierh. (Acanthaceae) in the Nicobar archipelago. Ocean and Coastal Research, 70. DOI: https://doi.org/10.1590/2675-2824070.21077vt
https://doi.org/10.1590/2675-2824070.210...
), previously unknown to the Nicobar Islands, were reported only after the 2004 tsunami, found colonizing the newly created intertidal habitats ( Nehru and Balasubramanian, 2012Nehru, P. & Balasubramanian, P. 2012. Sonneratia ovata Backer (Lythraceae): status and distribution of a near threatened mangrove species in tsunami impacted mangrove habitats of Nicobar Islands, India. Journal of Threatened Taxa, 4(15), 3395–3400. DOI: https://doi.org/10.11609/jott.o3009.3395-400
https://doi.org/10.11609/jott.o3009.3395...
; Thirumurugan et al., 2022Thirumurugan, V., Singh, A. R. & Prabakaran, N. 2022. First report on the occurrence of Avicennia marina (Forssk.) Vierh. (Acanthaceae) in the Nicobar archipelago. Ocean and Coastal Research, 70. DOI: https://doi.org/10.1590/2675-2824070.21077vt
https://doi.org/10.1590/2675-2824070.210...
). These new distributional reports are critical to understand the natural recovery and colonization pattern of this high ecological value coastal vegetation system.

Table 1
Details of mangrove species reported in the Nicobar archipelago before and after the 2004 tsunami (# – Reported by this study)

As a part of the long-term monitoring of the mangrove colonization in the Nicobar archipelago, we have collected a species belonging to the genus Aegiceras (Primulaceae) in Alreak, Noncowrie Island (7.99388° N, 93.52285° E). After a thorough scrutiny of relevant literature ( Parkinson, 1923Parkinson, C. E. 1923. The Forest Flora of the Andaman Islands: An Account of the Trees, Shrubs and Principal Climbers of the Islands. Dehradun: Bishen Singh Mahendra Pal Singh.; Tomlinson, 1986Tomlinson, P. B. 1986. The botany of mangroves. Cambridge: Cambridge University Press.; Dagar et al., 1991Dagar, J. C., Mongia, A. D. & Bandyopadhyay, A. K. 1991. Mangroves of Andaman and Nicobar Islands. Oxford: Oxford & IBH Pub. Co.; Ragavan et al., 2015Ragavan, P., Saxena, A., Mohan, P. M., Ravichandran, K., Jayaraj, R. S. C. & Saravanan, S. 2015. Diversity, distribution and vegetative structure of mangroves of the Andaman and Nicobar Islands, India. Journal of Coastal Conservation, 19(4), 417–443. DOI: https://doi.org/10.1007/s11852-015-0398-4
https://doi.org/10.1007/s11852-015-0398-...
), the species was identified as A. corniculatum (L.) Blanco. The occurrence of this species forms a new distributional record for the Nicobar group of Islands. This article provides detailed information on the species ecology, taxonomy with photographs, and distribution to facilitate the precise identification of the species.

The Nicobar archipelago is a part of the Sundaland biodiversity hotspot and denoted as one of the 25 micro-centers of endemism in India ( Nayar, 1996Nayar, M. P. 1996. Hot spots of endemic plants of India, Nepal and Bhutan. Palode: Tropical Botanic Garden and Research Institute.). The Nicobar archipelago comprises 21 islands with 1841 Km 2 and constitutes three major island groups, i.e., the Northern, Central, and Southern groups. Intensive field surveys were carried out across the archipelago to investigate the post-tsunami colonization of mangrove species from 2009 to 2011, and 2019 to 2022. These surveys have focused on documenting the species richness, community composition, and the rate of vegetation change in the newly created inter-tidal zones where mangrove species are found colonizing ( Nehru and Balasubramanian, 2012Nehru, P. & Balasubramanian, P. 2012. Sonneratia ovata Backer (Lythraceae): status and distribution of a near threatened mangrove species in tsunami impacted mangrove habitats of Nicobar Islands, India. Journal of Threatened Taxa, 4(15), 3395–3400. DOI: https://doi.org/10.11609/jott.o3009.3395-400
https://doi.org/10.11609/jott.o3009.3395...
, 2014Goutham-Bharathi, M., Roy, S., Krishnan, P., Kaliyamoorthy, M. & Immanuel, T. 2014. Species diversity and distribution of mangroves in Andaman and Nicobar Islands, India. Botanica Marina, 57(6), 421–432. DOI: https://doi.org/10.1515/bot-2014-0033
https://doi.org/10.1515/bot-2014-0033...
, 2018Nehru, P. & Balasubramanian, P. 2018. Mangrove species diversity and composition in the successional habitats of Nicobar Islands, India: A post-tsunami and subsidence scenario. Forest Ecology and Management, 427, 70–77. DOI: https://doi.org/10.1016/j.foreco.2018.05.063
https://doi.org/10.1016/j.foreco.2018.05...
; Prabakaran et al., 2021Prabakaran, N., Bayyana, S., Vetter, K. & Reuter, H. 2021. Mangrove recovery in the Nicobar archipelago after the 2004 tsunami and coastal subsidence. Regional Environmental Change, 21(3), 87. DOI: https://doi.org/10.1007/s10113-021-01811-0
https://doi.org/10.1007/s10113-021-01811...
; Thirumurugan et al., 2022Thirumurugan, V., Singh, A. R. & Prabakaran, N. 2022. First report on the occurrence of Avicennia marina (Forssk.) Vierh. (Acanthaceae) in the Nicobar archipelago. Ocean and Coastal Research, 70. DOI: https://doi.org/10.1590/2675-2824070.21077vt
https://doi.org/10.1590/2675-2824070.210...
). During our recent survey in April 2022, A. corniculatum was documented from a single site: Alreak, Noncowrie Islands, Central Nicobar group. A line transect consisting of six plots (10 m × 10 m), equally distanced at 50 m intervals from landward to seaward zone, was established for species enumeration (individuals ≥1 cm girth at breast height – GBH) and future monitoring of the site ( Figure 1). Additionally, all the individuals of A. corniculatum from the site were also counted. The GPS location, species abundance, and detailed site-specific information along with fresh flowering and fruiting specimens of Aegiceras were collected for the preparation of herbarium.

Figure 1.
Schematic representation of sampling plots along a transect line used for vegetation monitoring in the mangrove sites across the Nicobar archipelago.

Site description: The site Alreak (Nicobarese: Al = in front; reak = fresh water) is situated on the north-western part of Noncowrie Island in the Central Nicobar ( Figure 2). The mangrove vegetation of Alreak was completely lost, except for a few individuals of Nypa fruticans, after the tsunami and coastal subsidence. Currently, mangroves are seen sparsely colonizing in the newly formed intertidal areas. The remnants of pre-tsunami mangrove vegetation can be seen today in the form of dead trees in the shallow waters ( Figure 3). The topography is flat with mud clays (up to 50 cm belowground) near the seaward side. The seaward soil is humus-rich, dark in color, mostly muddy-clay, and more compact, while the soil in the landward side is firm and sandy. The site was fed by perennial freshwater streams, and dead corals were seen close to the freshwater stream. The water salinity ranges from 09 to 24 ppt, pH ranges from 6.5–7.8, and the total dissolved solvents (TDS) ranges from 300–400 ppm.

Figure 2.
Locations of sites surveyed for mangrove colonization in Nicobar archipelago indicating the Aegiceras corniculatum presence in Alreak, Central Nicobar.

Figure 3.
Aerial image showing the extent of dead mangrove vegetation and new colonizing mangroves at Alreak site in Nancowrie Island, Central Nicobar.

Taxonomy

Aegiceras corniculatum (L.) Blanco, Fl. Filip.: 79. 1837. Rhizophora corniculata L., Herb.

Amb.: 13. 1754.

This species is characterized as a shrub or small tree with stilt roots, up to 3 m high; stems c. 15 cm in diameter at base; young branches 4-angled, brown with reddish tinge, glabrous. Leaves are alternate, obovate, 3.5–9 × 1.5–4 cm, attenuate base, entire to minutely revolute margins, retuse apex, coriaceous, shiny, glabrous, green above, glaucous beneath; lateral veins 6–12 pairs, conspicuous above; petioles sub-sessile, up to 5 mm long. Inflorescence is umbel, terminal, with 12–35-flowers; flowers are 12–20 mm long, pentamerous, bisexual, white, fragrant; pedicels 6–10 mm long, glabrous. Sepals 5, aposepalous, oblong, 4–7 × 2–3 mm, green, glabrous. Corolla tubular, sympetalous, 5-lobed; lobes lance-ovate, 7–15 mm long, reflexed, glabrous. Stamens 5, 4–6 mm long; anthers linear-oblong, 3–4 mm long, dorsifixed. Ovary inferior; style c.9 mm long; stigma simple. Capsules terete to cylindrical, falcate, 4–9 cm long, pointed at apex, pale green when young, pink at maturity; seed 1, crypto viviparous; hypocotyl curved, pointed.

Flowering and fruiting: February–May ( Figure 4)

Specimen Examined: India, Nicobar Islands, Central Nicobar Islands, Alreak in Nancowrie Island, 7.99388° N, 93.52285° E, 14th April 2022, Thirumurugan Vedagiri, 12751, (Madras Christian College Herbarium, Chennai).

Figure 4.
A. View of Alreak, Nancowrie – A new intertidal mangrove habitat; B. Aegiceras corniculatum habit with new recruitments; C. Flowering twig with inflorescence; D. Bud; E. Flower; F. Fruits.

A total of 35 sites ( Figure 2) were surveyed across the Nicobar Island during 2009–2011 ( Nehru and Balasubramanian, 2018Nehru, P. & Balasubramanian, P. 2018. Mangrove species diversity and composition in the successional habitats of Nicobar Islands, India: A post-tsunami and subsidence scenario. Forest Ecology and Management, 427, 70–77. DOI: https://doi.org/10.1016/j.foreco.2018.05.063
https://doi.org/10.1016/j.foreco.2018.05...
). During our recent field survey, conducted from February to May 2022, across 19 mangrove sites in the Nicobar archipelago, we collected Aegiceras corniculatum (L.) Blanco, a new distribution record from the single site of Alreak, Nancowrie Island (Central Nicobar). The other mangrove species collected from Alreak were: Nypa fruticans Wurmb , Bruguiera gymnorhiza (L.) Lam. , Rhizophora mucronata Lam. , Dolichandrone spathacea (L.f.) Seem. , and Heritiera littoralis Aiton. Aegiceras corniculatum dominated the seaward zone at Alreak, while Nypa fruticans dominated the landward zone where the soil was muddy with continuous freshwater input.

We counted 40 small trees (ranged between 1.5–3m height), and ~260 seedlings of Aegiceras corniculatum from the entire site. Additionally, one tree (~45 cm Girth at Breast Height (GBH)) and few seedlings of Rhizophora mucronata were occasionally present across the site. The site also withheld small Rhizophora mucronata plantation block recently planted by the forest department (approx. two years old).

At Alreak, A. corniculatum (Relative abundance (RA) = 54.02%) was the most abundant species followed by N. fruticans (RA = 44.83%), and R. mucronata (RA = 1.15%). 19 small trees (around 2 m in height), and 30 seedlings were encountered in the survey plots. A. corniculatum was found growing in scattered patches (clump of 10–15 small trees) mostly along the creek channel.

A. corniculatum is widespread (7,400 km coastal area) across the Indo-West Pacific region, ranging from Pakistan to South China, to Tropical Asia through Malaysia to Polynesia and North-Eastern Australia ( Tomlinson, 1986Tomlinson, P. B. 1986. The botany of mangroves. Cambridge: Cambridge University Press.; Clarke et al., 2001Clarke, P. J., Kerrigan, R. A. & Westphal, C. J. 2001. Dispersal Potential and Early Growth in 14 Tropical Mangroves: Do Early Life History Traits Correlate with Patterns of Adult Distribution? Journal of Ecology, 89(4), 648–659.). In India, the species is distributed in all along the west and east coast ( Ragavan et al., 2016Ragavan, P., Saxena, A., Jayaraj, R. S. C., Mohan, P. M., Ravichandran, K., Saravanan, S. & Vijayaraghavan, A. 2016. A review of the mangrove floristics of India. Taiwania, 61(3), 224–242.). This species is reported from various sites in the Andaman Islands ( Parkinson, 1923Parkinson, C. E. 1923. The Forest Flora of the Andaman Islands: An Account of the Trees, Shrubs and Principal Climbers of the Islands. Dehradun: Bishen Singh Mahendra Pal Singh.; Dagar et al., 1991Dagar, J. C., Mongia, A. D. & Bandyopadhyay, A. K. 1991. Mangroves of Andaman and Nicobar Islands. Oxford: Oxford & IBH Pub. Co.; Debnath, 1994Debnath, H. 1994. Systematic Notes on Mangroves of Andaman and Nicobar Islands. In: Conservation of Mangrove Forest Genetic Resources (pp. 145--148). Madras: M.S. Swaminathan Research Foundation.; Goutham-Bharathi et al., 2014Goutham-Bharathi, M., Roy, S., Krishnan, P., Kaliyamoorthy, M. & Immanuel, T. 2014. Species diversity and distribution of mangroves in Andaman and Nicobar Islands, India. Botanica Marina, 57(6), 421–432. DOI: https://doi.org/10.1515/bot-2014-0033
https://doi.org/10.1515/bot-2014-0033...
; Ragavan et al., 2015Ragavan, P., Saxena, A., Mohan, P. M., Ravichandran, K., Jayaraj, R. S. C. & Saravanan, S. 2015. Diversity, distribution and vegetative structure of mangroves of the Andaman and Nicobar Islands, India. Journal of Coastal Conservation, 19(4), 417–443. DOI: https://doi.org/10.1007/s11852-015-0398-4
https://doi.org/10.1007/s11852-015-0398-...
) In the Andaman Islands, A. corniculatum in generally found along the creek margin, and it dominates the areas of the medium to high salinity conditions. Although, a checklist of plants in Andaman and Nicobar Islands by Pandey and Diwakar ( 2008Pandey, R. P. & Diwakar, P. O. 2008. An integrated check-list flora of Andaman and Nicobar Islands, India. Journal of Economic and Taxonomic Botany, 32(2), 403–500.) reported the distribution of this Aegiceras from the Nicobar Islands, this report was not substantiated with any evidence (i.e. herbarium specimen, information of distribution localities, ecology, etc.). Our observation confirms the distribution of A. corniculatum in the Nicobar Islands with the specimen deposited at the Madras Christian College Herbarium (Thirumurugan 12751) along with documentation of its distribution and habitat specific information.

Aegiceras corniculatum is a pioneer mangrove species that usually grows along the margins of estuary banks ( Tomlinson, 1986Tomlinson, P. B. 1986. The botany of mangroves. Cambridge: Cambridge University Press.; Clarke et al., 2001Clarke, P. J., Kerrigan, R. A. & Westphal, C. J. 2001. Dispersal Potential and Early Growth in 14 Tropical Mangroves: Do Early Life History Traits Correlate with Patterns of Adult Distribution? Journal of Ecology, 89(4), 648–659.). It has diffuse-porous wood, which is adapted for different soil salinities ( Sun and Lin, 1997Sun, Q. & Lin, P. 1997. Wood structure of Aegiceras corniculatum and its ecological adaptations to salinities. Hydrobiologia, 352(1/3), 61–65. DOI: https://doi.org/10.1023/a:1003092906969
https://doi.org/10.1023/a:1003092906969...
). A. corniculatum is a crypto viviparous species with adaptability towards high salinity conditions (has eight salt tolerance-related genes) via the salt secretion glands present in the leaves to survive and adapt against saline and hypoxic conditions of intertidal forest ( Feng et al., 2021Feng, X., Li, G., Xu, S., Wu, W., Chen, Q., Shao, S., Liu, M., Wang, N., Zhong, C., He, Z. & Shi, S. 2021. Genomic insights into molecular adaptation to intertidal environments in the mangrove Aegiceras corniculatum. New Phytologist, 231(6), 2346–2358. DOI: https://doi.org/10.1111/nph.17551
https://doi.org/10.1111/nph.17551...
; Khan et al., 2021Khan, D., Zaki, M. J. & Ali, S. V. 2021. Some observations on mangrove species, Aegiceras corniculatum (l.) Blanco of Pakistan with reference to propagule, sapling and sapling leaf. International Journal of Biology and Biotechnology, 18(2), 389–406.). It excludes 97% salt through gland/surface opening rather than metabolic mechanism ( Hogarth, 2013Hogarth, P. 2013. Mangrove Ecosystems. In: Encyclopedia of Biodiversity (pp. 10–22). Elsevier. DOI: https://doi.org/10.1016/b978-0-12-384719-5.00247-1
https://doi.org/10.1016/b978-0-12-384719...
) and can also resist other environmental stresses, such as shade, moisture, and chilling stress ( Peng et al., 2015Peng, Y.-L., Wang, Y.-S., Fei, J., Sun, C.-C. & Cheng, H. 2015. Ecophysiological differences between three mangrove seedlings (Kandelia obovata, Aegiceras corniculatum, and Avicennia marina) exposed to chilling stress. Ecotoxicology, 24(7–8), 1722–1732. DOI: https://doi.org/10.1007/s10646-015-1488-7
https://doi.org/10.1007/s10646-015-1488-...
). The propagules of A. corniculatum are buoyant and float in the sea for up to three months until it reaches the conducive environment ( Clarke, 1995Clarke, P. J. 1995. The population dynamics of the mangrove shrub Aegiceras corniculatum (Myrsinaceae): fecundity, dispersal, establishment and population structure. In: Proceedings of The Linnean Society of New South Wales (Vol. 15, pp. 35–44).; Tomlinson, 2016Tomlinson, P. B. 2016. The Botany of Mangroves. Cambridge: Cambridge University Press. DOI: https://doi.org/10.1017/cbo9781139946575
https://doi.org/10.1017/cbo9781139946575...
). Therefore, propagules of A. corniculatum have a long-distance dispersal ability ( Clarke, 1995Clarke, P. J. 1995. The population dynamics of the mangrove shrub Aegiceras corniculatum (Myrsinaceae): fecundity, dispersal, establishment and population structure. In: Proceedings of The Linnean Society of New South Wales (Vol. 15, pp. 35–44).; Clarke et al., 2001Clarke, P. J., Kerrigan, R. A. & Westphal, C. J. 2001. Dispersal Potential and Early Growth in 14 Tropical Mangroves: Do Early Life History Traits Correlate with Patterns of Adult Distribution? Journal of Ecology, 89(4), 648–659.). Their ability to disperse over long distances and their adaptability to establish and survive in high saline areas are typical attributes of seaward mangrove zones in the new intertidal areas of Nicobar Islands. These attributes have likely facilitated the establishment of A. corniculatum in Nicobar Islands. However, further studies focusing on genetics aspects is required to assume the source of propagule dispersal that potentially enabled a new population establishment in the Nicobar Islands.

The post-tsunami studies indicated an increase in the dominance of saline-tolerant species in the Nicobar Islands ( Goutham-Bharathi et al., 2014Goutham-Bharathi, M., Roy, S., Krishnan, P., Kaliyamoorthy, M. & Immanuel, T. 2014. Species diversity and distribution of mangroves in Andaman and Nicobar Islands, India. Botanica Marina, 57(6), 421–432. DOI: https://doi.org/10.1515/bot-2014-0033
https://doi.org/10.1515/bot-2014-0033...
; Ragavan et al., 2015Ragavan, P., Saxena, A., Mohan, P. M., Ravichandran, K., Jayaraj, R. S. C. & Saravanan, S. 2015. Diversity, distribution and vegetative structure of mangroves of the Andaman and Nicobar Islands, India. Journal of Coastal Conservation, 19(4), 417–443. DOI: https://doi.org/10.1007/s11852-015-0398-4
https://doi.org/10.1007/s11852-015-0398-...
; Nehru and Balasubramanian, 2018Nehru, P. & Balasubramanian, P. 2018. Mangrove species diversity and composition in the successional habitats of Nicobar Islands, India: A post-tsunami and subsidence scenario. Forest Ecology and Management, 427, 70–77. DOI: https://doi.org/10.1016/j.foreco.2018.05.063
https://doi.org/10.1016/j.foreco.2018.05...
; Thirumurugan et al., 2022Thirumurugan, V., Singh, A. R. & Prabakaran, N. 2022. First report on the occurrence of Avicennia marina (Forssk.) Vierh. (Acanthaceae) in the Nicobar archipelago. Ocean and Coastal Research, 70. DOI: https://doi.org/10.1590/2675-2824070.21077vt
https://doi.org/10.1590/2675-2824070.210...
). This is also supported by the recent discovery of Avicennia marina, which has a rapid colonizing strategy in Nicobar’s new intertidal habitats ( Thirumurugan et al., 2022Thirumurugan, V., Singh, A. R. & Prabakaran, N. 2022. First report on the occurrence of Avicennia marina (Forssk.) Vierh. (Acanthaceae) in the Nicobar archipelago. Ocean and Coastal Research, 70. DOI: https://doi.org/10.1590/2675-2824070.21077vt
https://doi.org/10.1590/2675-2824070.210...
). Similarly, despite being recorded from just one site in Nicobar Islands, and given its ability to establish in challenging conditions and to disperse long-distances, A. corniculatum has a greater chance to spread across the Central Nicobar Islands and neighboring intertidal habitats. However, long-term monitoring of new intertidal habitats in the Nicobar archipelago would be essential to understand not only the future spread of A. corniculatum, but also the mangrove forest successional dynamics, and species competitions that can provide significant knowledge for mangrove management.

  • This work was supported by the Department of Science and Technology under the INSPIRE Faculty scheme [DST/INSPIRE/04/2018/001071]

ACKNOWLEDGMENTS

This work was supported by the Department of Science and Technology under the INSPIRE Faculty scheme [DST/INSPIRE/04/2018/001071]. We thank the Department of Environment and Forest of the Andaman and Nicobar Islands for the necessary permission and for facilitating the fieldwork. We are thankful to the Dean, Director, Faculties, and researchers of Wildlife Institute of India for the encouragement and constant support. Also, we are thankful to the Head of the Department of Botany and the Principal of Madras Christian College (Autonomous) for providing facilities.

References

  • Alongi, D. M. 2008. Mangrove forests: Resilience, protection from tsunamis, and responses to global climate change. Estuarine, Coastal and Shelf Science, 76(1), 1–13. DOI: https://doi.org/10.1016/j.ecss.2007.08.024
    » https://doi.org/10.1016/j.ecss.2007.08.024
  • Chakrabarthy, T. 1985. Excoecaria indica (Euphorbiaceae) on Great Nicobar Island. Journal of Economic and Taxonomic Botany, 6, 438.
  • Clarke, P. J. 1995. The population dynamics of the mangrove shrub Aegiceras corniculatum (Myrsinaceae): fecundity, dispersal, establishment and population structure. In: Proceedings of The Linnean Society of New South Wales (Vol. 15, pp. 35–44).
  • Clarke, P. J., Kerrigan, R. A. & Westphal, C. J. 2001. Dispersal Potential and Early Growth in 14 Tropical Mangroves: Do Early Life History Traits Correlate with Patterns of Adult Distribution? Journal of Ecology, 89(4), 648–659.
  • Dagar, J. C., Mongia, A. D. & Bandyopadhyay, A. K. 1991. Mangroves of Andaman and Nicobar Islands. Oxford: Oxford & IBH Pub. Co.
  • Dagar, J. C., Singh, N. T. & Mongia, A. D. 1993. Characteristics of mangrove soils and vegetation of Bay Islands in India. In: Towards the rational use of high salinity tolerant plants (pp. 59–80). Springer Netherlands. DOI: https://doi.org/10.1007/978-94-011-1858-3_6
    » https://doi.org/10.1007/978-94-011-1858-3_6
  • Debnath, H. 1994. Systematic Notes on Mangroves of Andaman and Nicobar Islands. In: Conservation of Mangrove Forest Genetic Resources (pp. 145--148). Madras: M.S. Swaminathan Research Foundation.
  • Feng, X., Li, G., Xu, S., Wu, W., Chen, Q., Shao, S., Liu, M., Wang, N., Zhong, C., He, Z. & Shi, S. 2021. Genomic insights into molecular adaptation to intertidal environments in the mangrove Aegiceras corniculatum. New Phytologist, 231(6), 2346–2358. DOI: https://doi.org/10.1111/nph.17551
    » https://doi.org/10.1111/nph.17551
  • Gopinathan, C. P. & Rajagopalan, M. S. 1983. Mangrove resources. CMFRI Bulletin, 34, 44–46.
  • Goutham-Bharathi, M., Roy, S., Krishnan, P., Kaliyamoorthy, M. & Immanuel, T. 2014. Species diversity and distribution of mangroves in Andaman and Nicobar Islands, India. Botanica Marina, 57(6), 421–432. DOI: https://doi.org/10.1515/bot-2014-0033
    » https://doi.org/10.1515/bot-2014-0033
  • Hogarth, P. 2013. Mangrove Ecosystems. In: Encyclopedia of Biodiversity (pp. 10–22). Elsevier. DOI: https://doi.org/10.1016/b978-0-12-384719-5.00247-1
    » https://doi.org/10.1016/b978-0-12-384719-5.00247-1
  • Jagtap, T. G. 1992. Marine flora of Nicobar group of islands in Andaman Sea. Indian Journal of Marine Sciences, 21(1), 56–58.
  • Khan, D., Zaki, M. J. & Ali, S. V. 2021. Some observations on mangrove species, Aegiceras corniculatum (l.) Blanco of Pakistan with reference to propagule, sapling and sapling leaf. International Journal of Biology and Biotechnology, 18(2), 389–406.
  • Krauss, K. W. & Osland, M. J. 2020. Tropical cyclones and the organization of mangrove forests: a review. Annals of Botany. DOI: https://doi.org/10.1093/aob/mcz161
    » https://doi.org/10.1093/aob/mcz161
  • Nayar, M. P. 1996. Hot spots of endemic plants of India, Nepal and Bhutan. Palode: Tropical Botanic Garden and Research Institute.
  • Nehru, P. & Balasubramanian, P. 2011. Re-colonizing mangrove species in tsunami devastated habitats at Nicobar Islands, India. Check List, 7(3), 253–256. DOI: https://doi.org/10.15560/7.3.253
    » https://doi.org/10.15560/7.3.253
  • Nehru, P. & Balasubramanian, P. 2012. Sonneratia ovata Backer (Lythraceae): status and distribution of a near threatened mangrove species in tsunami impacted mangrove habitats of Nicobar Islands, India. Journal of Threatened Taxa, 4(15), 3395–3400. DOI: https://doi.org/10.11609/jott.o3009.3395-400
    » https://doi.org/10.11609/jott.o3009.3395-400
  • Nehru, P. & Balasubramanian, P. 2018. Mangrove species diversity and composition in the successional habitats of Nicobar Islands, India: A post-tsunami and subsidence scenario. Forest Ecology and Management, 427, 70–77. DOI: https://doi.org/10.1016/j.foreco.2018.05.063
    » https://doi.org/10.1016/j.foreco.2018.05.063
  • Pandey, R. P. & Diwakar, P. O. 2008. An integrated check-list flora of Andaman and Nicobar Islands, India. Journal of Economic and Taxonomic Botany, 32(2), 403–500.
  • Parkinson, C. E. 1923. The Forest Flora of the Andaman Islands: An Account of the Trees, Shrubs and Principal Climbers of the Islands. Dehradun: Bishen Singh Mahendra Pal Singh.
  • Peng, Y.-L., Wang, Y.-S., Fei, J., Sun, C.-C. & Cheng, H. 2015. Ecophysiological differences between three mangrove seedlings (Kandelia obovata, Aegiceras corniculatum, and Avicennia marina) exposed to chilling stress. Ecotoxicology, 24(7–8), 1722–1732. DOI: https://doi.org/10.1007/s10646-015-1488-7
    » https://doi.org/10.1007/s10646-015-1488-7
  • Platt, W. J. & Connell, J. H. 2003. Natural Disturbances and Directional Replacement of Species. Ecological Monographs, 73(4), 507–522.
  • Prabakaran, N. 2020. Mangrove community response to subsidence inflicted sea level change in Car Nicobar Island, India. Botanica Marina, 63(5), 419–427. DOI: https://doi.org/10.1515/bot-2019-0088
    » https://doi.org/10.1515/bot-2019-0088
  • Prabakaran, N., Bayyana, S., Vetter, K. & Reuter, H. 2021. Mangrove recovery in the Nicobar archipelago after the 2004 tsunami and coastal subsidence. Regional Environmental Change, 21(3), 87. DOI: https://doi.org/10.1007/s10113-021-01811-0
    » https://doi.org/10.1007/s10113-021-01811-0
  • Ragavan, P., Saxena, A., Jayaraj, R. S. C., Mohan, P. M., Ravichandran, K., Saravanan, S. & Vijayaraghavan, A. 2016. A review of the mangrove floristics of India. Taiwania, 61(3), 224–242.
  • Ragavan, P., Saxena, A., Mohan, P. M., Ravichandran, K., Jayaraj, R. S. C. & Saravanan, S. 2015. Diversity, distribution and vegetative structure of mangroves of the Andaman and Nicobar Islands, India. Journal of Coastal Conservation, 19(4), 417–443. DOI: https://doi.org/10.1007/s11852-015-0398-4
    » https://doi.org/10.1007/s11852-015-0398-4
  • Sinha, B. K. 1999. Flora of Great Nicobar Island. Dehra Dun: Botanical Survey of India.
  • Sun, Q. & Lin, P. 1997. Wood structure of Aegiceras corniculatum and its ecological adaptations to salinities. Hydrobiologia, 352(1/3), 61–65. DOI: https://doi.org/10.1023/a:1003092906969
    » https://doi.org/10.1023/a:1003092906969
  • Thirumurugan, V., Singh, A. R. & Prabakaran, N. 2022. First report on the occurrence of Avicennia marina (Forssk.) Vierh. (Acanthaceae) in the Nicobar archipelago. Ocean and Coastal Research, 70. DOI: https://doi.org/10.1590/2675-2824070.21077vt
    » https://doi.org/10.1590/2675-2824070.21077vt
  • Thothathri, K., Banerjee, S. P., Mukherjee, P. K., Hajra, P. K. & Pal, G. D. 1973. Botanical Results of the Joint Scientific Expedition to the Great Nicobar Island. Nelumbo, 15(3–4), 235–265.
  • Tomlinson, P. B. 1986. The botany of mangroves. Cambridge: Cambridge University Press.
  • Tomlinson, P. B. 2016. The Botany of Mangroves. Cambridge: Cambridge University Press. DOI: https://doi.org/10.1017/cbo9781139946575
    » https://doi.org/10.1017/cbo9781139946575
  • White, P. S. 1979. Pattern, process, and natural disturbance in vegetation. The Botanical Review, 45(3), 229–299. DOI: https://doi.org/10.1007/bf02860857
    » https://doi.org/10.1007/bf02860857

Edited by

Editor:

Rubens M. Lopes

Associate Editor:

Cintia Quintana

Publication Dates

  • Publication in this collection
    04 Dec 2023
  • Date of issue
    2023

History

  • Received
    01 Feb 2023
  • Accepted
    12 May 2023
Instituto Oceanográfico da Universidade de São Paulo Praça do Oceanográfico 191, CEP: 05508-120, São Paulo, SP - Brasil, Tel.: (11) 3091-6501 - São Paulo - SP - Brazil
E-mail: diretoria.io@usp.br