Abstract
The palm resources of Andaman & Nicobar Islands are quite rich and unique with a substantial number of endemic species. Andaman & Nicobar Islands, falling within the Indo-Burma region constitute “hottest hotspot” of global biodiversity with an exceptional concentration of endemic species, but are experiencing alarming loss of habitat. The flora and fauna of Andaman group of islands show striking dissimilarities with that of Nicobar group. Palms such as Arenga pinnata, A. westerhoutii, Calamus baratangensis, C. basui, C. longisetus, C. palustris, C. viminalis, Corypha utan, Daemonorops aurea, D. kurziana, D. manii, D. rarispinosa, D. wrightmyoensis, Korthalsia rogersii, Licuala spinosa, Phoenix andamanensis, and Pinanga andamanensis which occur in Andaman groups of islands are absent in the Nicobar group of islands. While Bentinckia nicobarica, Calamus dilaceratus, C. nicobaricus, C. pseudorivalis, C. semierectus, C. unifarius, and Rhopaloblaste augusta are confined to the Nicobars, but seldom found in the Andamans. Areca triandra, Calamus andamanicus, Caryota mitis, Korthalsia laciniosa, Licuala peltata and Pinanga manii are widely distributed in both the group of islands. There is a considerable reduction in their natural population probably due to habitat destruction, low regeneration, and inability to compete with other plants. In addition, calamities like tsunami caused irrecoverable loss of valuable genetic diversity of palms. If conservation efforts are not undertaken, many of the existing species, if not all, are likely to disappear within a foreseeable future. There is dire need for habitat preservation and for in situ conservation. Appropriate conservation strategies should be taken to prevent further genetic erosion of these species and to protect these invaluable plant resources.
Similar content being viewed by others
Avoid common mistakes on your manuscript.
Introduction
India, one of the 17 mega biodiversity countries, nurtures 8% of the world’s biodiversity. It has highest diversity of ecosystems in the form of forests, wetlands, grasslands, marine areas, deserts, glaciers, and mangroves. Henderson (2009) mentions that there are about 18 genera and 88 species of palms known from India, but our KFRI database (unpublished) reveals that there are 21 genera and 105 species of palms occurring in three major geographical regions viz., Peninsular India, North eastern India, and Andaman & Nicobar Islands. A small number of palm species also occur in the Gangetic plains and in the lower hill valleys of Northern India. In addition to indigenous species of palms, several exotics are cultivated as ornamentals.
The Andaman & Nicobar Islands, geologically a continuation of the Arakan Yoma, the largest archipelago system in the Bay of Bengal and consisting of a group of 572 large and small islands and islets, are situated between the latitudes of 6°–14°N and the longitudes of 92° to 94°E, and constitute one of the “hottest hotspots” of biodiversity (Myers et al. 2000). This island complex is unique and being the only habitat of its type on the Indian subcontinent, exhibits a vivid and spectacular biodiversity because of its tropical humid climate and insular nature. Most of the islands are covered with luxuriant vegetation. Although several authors have investigated the flora of the Andaman & Nicobar Islands (Balakrishnan 1977, 1989; Ellis 1989; Mathew and Abraham 1994; Mathew et al. 2007; Parkinson 1923; Rao 1986; Subbarao 1989; Thothathri 1977), very little information exists on the palm wealth, their status, and their conservation. Many parts of the territory are still unexplored or underexplored and therefore our knowledge of palms is inadequate. Moreover, a substantial number of species are endemics.
Methodology
Kerala Forest Research Institute had conducted a field survey for the palms of Andaman & Nicobar Islands during the period 1992–1995 (Renuka 1995). Another field survey was taken up during 2008 by the first two authors, which helped to record the present account on distribution and conservation status of palms in these islands. Identity of the specimens was established by referring to the herbarium material lodged in herbaria of KFRI, Peechi and BSI, Andamans. Earlier works are Beccari (1908, 1911, 1918), Blatter (1926), Brandis (1874), Griffith (1844–1845), Hooker (1872–1897), Parkinson (1923), Renuka (1995), Sasha Barrow (1998), and Uhl and Dransfield (1987). Voucher herbarium specimens prepared for all palms collected are deposited in the Herbarium of Kerala Forest Research Institute, Peechi, Kerala. For knowing distributional status in other parts of the world, Kew check list of palms was consulted (Govaerts et al. 2006). For assessing the diversity status, species richness, geographic rarity or endemism and taxonomic singularity or distinctiveness (number of species within each genus) approach of Ojeda et al. (1995) was followed.
Results and discussion
Andaman & Nicobar Islands with a highly diverse set of biomes comprising 0.03% of the country’s landmass are characterized by a distinctive flora and consist of several rare and endemic taxa. This is particularly true of palms, which are represented by 13 genera and 33 species. Of the 13 genera of palms, 5 genera—Bentinckia, Caryota, Corypha, Nypa, and Rhopaloblaste—are monotypic. The present study has revealed that the islands are rich in rattan flora comprising of three genera viz. Calamus (11 species), Daemonorops (5 species), and Korthalsia (2 species) (Renuka 1995, 1999; Henderson, 2009). Interestingly, palms such as Arenga pinnata, A. westerhoutii, Corypha utan, Licuala spinosa, Phoenix andamanensis, Pinanga andamanensis, Calamus baratangensis, C. basui, C. longisetus, C. palustris, C. viminalis, Daemonorops aurea, D. kurziana, D. manii, D. rarispinosa, D. wrightmyoensis, and Korthalsia rogersii which are present in Andamans do not occur in the Nicobars. While Bentinckia nicobarica, Rhopaloblaste augusta, Calamus dilaceratus, C. nicobaricus, C. pseudorivalis, C. semierectus, and C. unifarius are confined to the Nicobars but seldom found in the Andamans. Areca triandra, Calamus andamanicus, Caryota mitis, Korthalsia laciniosa, Licuala peltata, and Pinanga manii are widely distributed in both the group of islands. However, Henderson (2009) does not agree for the existence of Pinanga andamanensis. While the Andamans have more species common to NE India and Burma (viz. Areca triandra, Arenga pinnata, A. westerhoutii, Licuala peltata), the Nicobars as reported by Balakrishnan (1989) have more in common with Indonesia and Malaysia (Licuala sp., Nypa sp.). Calamus palustris and C. longisetus found in S. Andaman are also reported from Malaysia and S. China. Calamus viminalis found in S. Andaman is reported from South Central China and mainland of India.
New reports
Recently, the authors located one more palm namely, Arenga pinnata (Wurmb.) Merr. in the vicinity of Austin I & II near Mayabunder of Middle Andamans. Although this taxon is widespread in NE India, it was not recorded from Andaman & Nicobar Islands. The present collection establishes the extended distribution of the taxon in Andaman Islands. Further, the occurrence of this taxon is reported from South China to Central Malaysia depicting its disjunctive distribution. During present collection, we were able to locate Calamus dilaceratus from Laful bay which is a protected reserve for Shompen tribes, Calamus unifarius from Car Nicobar and Korthalsia rogersii in Chidiya Tapu (S. Andaman) and in forest areas of Parnasala near Rangat (Middle Andaman). The present collection establishes the extended distribution of the taxa in Andaman & Nicobar Is. Earlier Calamus dilaceratus is reported from East–West Road (Great Nicobar), Calamus unifarious from Katachal, Kamorta, Galathea (Nicobar Island) and Korthalsia rogersii from Diglipur (N. Andaman) and Havlock Island (S. Andaman). Phoenix andamanensis was reported from Saddle peak at 700 m above MSL, in the eastern slope of Mt. Ford, Cinque Island and Rutland Island (Brandis 1906; Parkinson 1923). The authors also found this taxon in Kalighat (Diglipur District) in the vicinity of hydro electric power station.
Endemism
The most remarkable feature of Andaman & Nicobar Islands is the high level of endemism of palms both at generic and species level (Balakrishnan 1977; Balakrishnan and Nair 1977; Ellis 1989; Subbarao 1989). Seven genera with a total of 18 species viz. Bentinckia nicobarica, Phoenix andamanensis, Pinanga andamanensis, Pinanga manii, Rhopaloblaste augusta, Calamus andamanicus, C. baratangensis, C. basui, C. dilaceratus, C. nicobaricus, C. pseudorivalis, C. semierectus, C. unifarius var. pentong, Daemonorops aurea, D. manii, D. rarispinosa, D. wrightmyoensis, and Korthaslsia rogersii are endemic to these islands. Among the non-endemic palms (about 14%), Calamus longisetus, C. palustris, and Daemonorops kurziana are not found in the mainland India, but have only extra-Indian distribution in China, Peninsular Malaysia, W. Thailand, and Lesser Sunda. Table 1 gives the analysis of species distribution, number of endemics, and number of taxa occurring in mainland India and elsewhere to assess their percentage. Andamans have one species (Calamus viminalis) common to NE India, Bangladesh, and China to Indonesia. Four species are common to SE Asian countries. Calamus andamanicus is common to Andaman & Nicobar Islands. Other species of palms show very restricted distribution with approximately 5–10 individuals constituting a population. In addition, there are few palms introduced and grown as ornamentals (Table 2).
Threats to the diversity of palms
The palms in Andaman & Nicobar Islands have been under great threat due to various factors. In recent years, many of the native palm habitats are affected by ecological catastrophe like tsunami and anthropogenic factors placing several species in immediate danger of extinction. The taxa such as Arenga pinnata, Bentinckia nicobarica, Calamus basui, C. dilaceratus, C. semierectus, C. unifarius, Corypha utan, Daemonorops manii, D. rarispinosa, D. wrightmyoensis, Korthalsia rogersii, Nypa fruiticans, Phoenix andamanensis, Pinanga andamanensis, P. manii, and Rhopaloblaste augusta show very restricted distribution and their population size is small and places them under high threat of extinction. Some of the taxa like Bentinckia nicobarica, C. dilaceratus, Korthalsia rogersii, Nypa fruticans, Pinanga andamanensis, and P. manii are already mentioned in the Red Data Book as vulnerable (Ahmedulla and Nayar 1986). According to Sharma and Bhat (1982), Andaman & Nicobar Islands are referred as the last bastion of useful palms. Renuka (1995) reported that severe pressure from rattan industries in the mainland together with the unscientific extraction and over-exploitation of the raw materials resulted in the depletion of the rattan resources at a faster rate in some of the islands. Recent survey revealed that over-exploitation is continuing and the resource is disappearing rapidly. C. nicobaricus reported earlier could not be relocated during later surveys. When compared to the data collected during earlier survey, it is observed that there is considerable reduction in population size in the localities visited during the present study. Further, the massive earthquake followed by tsunami on December 26, 2004, has caused irrepairable damage to biodiversity. All 38 inhabited islands have been affected by this devastating episode. The astounding impact on vegetation loss is more in Nicobar groups of islands than in middle and South Andaman, and there was vast inundation of seawater in the low-lying areas. Middle Andaman, South Andaman, Little Andaman, Car Nicobar, Teressa, Katchal, Kamorta, Nancowry, Little Nicobar, and Great Nicobar islands were severely affected by tsunami. Vast forest areas which form natural habitat of the palms around Galathea bay, Indira Point, Chengappa Bay, and Laful Bay were completely destroyed by tsunami. Further, 5891 ha of damaged land pertain to plantation crops—coconut and arecanut (Official Report for the year 2006 from Andaman & Nicobar Islands Administration). During our field survey, it was found that the swamps and mangrove creeks in Shoal bay (South Andaman) and Austin I & II, and “D”-Sector near Mayabunder, which were once covered with dense population of Phoenix paludosa, were badly affected by tsunami (Fig. 1).
Rarity—cause for concern
Nearly half the world’s vascular plant species are endemic to 34 “hotspots” of biodiversity, each of which has at least 1500 endemics. None of these hotspots have more than one-third of their pristine habitat remaining. Historically, they covered 12% of the land’s surface, but today their intact habitat covers only 1.4% of the land. As a result of habitat loss, we expect many of the hotspot endemics to have either become extinct or be threatened with extinction (Brooks et al. 2002). Humans are the major cause of habitat alteration, climate change, and species endangerment (Woodruff 2010).
The first notable scientific activity related to palm conservation took place only about three decades ago, when Moore (1979) drew attention to the need for palm conservation which eventually led to formation of the IUCN Palm Specialist Group in 1984. Palm conservation is a complex and challenging task. Endemic island palm species are very important for biodiversity maintenance since many are monotypic. Our observation on the distribution of the species also revealed that most of the endemic species are highly habitat specific occurring in very limited localities and in small populations. Destruction of even a small forest area in these islands may cause complete extinction of the endemics. Apart from this, in most palm species, the seed viability decreases rapidly. Palm seed cannot be dried and kept under low temperature conditions because the embryo will be killed. Major botanic gardens can play a vital role with regard to palm conservation. As far as conservation is concerned, two major obstacles exist with respect to botanic gardens. They can preserve only a few specimens of any given species. They cannot, therefore, represent the range of characteristics found in wild relatives necessary to maintain the biological diversity. This is true with reference to the BSI Botanic Garden at Dhanikari and proposed Biological Park at Chidiya Tapu. Although, they form important biodiversity reservoirs helping in conservation of diverse taxa of plants, they cannot protect the genetic diversity of wild palms.
Most of the palm species are very rare and live at the brink of extinction. Therefore, conservation and sustainable utilization of palm resources assumes great importance in the current context, when forest wealth of the nation as a whole has been on the decline. Unless concrete efforts toward their replenishment are undertaken, some of these wild palms are likely to become extinction. For prevention of further genetic erosion of these species, the development and adoption of appropriate conservational strategies are very much warranted. The safeguarding of hotspots worldwide is the greatest biodiversity challenge of the foreseeable future. The need of the hour is to revive global conservation attention to this biologically rich, important but imperiled region. Comprehensive conservation programme worldwide would be an appropriate step in this direction.
Some strategies for conservation of palms are as follows:
-
Establishment of a palmetum with representation of all the species growing in the islands.
-
Establishment of gene banks and seed orchards.
-
Establishment of large scale palm plantation of commercially important species.
-
Understanding the reproductive biology and phenology of palm taxa which are very important for the selection of elite varieties and conservation.
-
Control on the exploitation of wild populations.
-
Check on the destruction of natural habitats.
-
Identifying specific pockets in the natural area of the occurrence of rattans and palms for in situ conservation.
-
Introduction of rare and threatened species into Botanic gardens, arboreta and other protected areas.
-
Evolving potentially useful methods for the propagation and improving the various existing methods.
References
Ahmedulla M, Nayar MP (1986) Endemic plants of the Indian region, vol I. Botanical Survey of India, Kolkata
Balakrishnan NP (1977) Recent botanical studies in Andaman and Nicobar Islands. Bull Bot Surv India 19:132–138
Balakrishnan NP (1989) Andaman Islands—vegetation and floristics. In: Saldanha CJ (ed) Andaman, Nicobar and Lakshadweep. An environmental impact assessment. Oxford and IBH Publishing Co. Pvt. Ltd, New Delhi, pp 55–69
Balakrishnan NP, Nair NG (1977) New records of plants from Andaman and Nicobar Islands. Indian For 103:638–640
Balakrishnan NP, Nair PB (1979) Wild populations of Areca and Cocos in Andaman & Nicobar Islands. Indian J For 2:350–363
Beccari O (1908) Asiatic palms—Lepidocaryeae, Part I. The species of Calamus. Ann R Bot Gard (Calcutta) 11:1–518
Beccari O (1911) Asiatic palms. Lepidocaryeae, Part 2. The species of Daemonorops. Ann R Bot Gard Calcutta 12(1):1–237
Beccari O (1918) Asiatic palms. Lepidocaryeae, Part 3. The species of the genera Ceratolobus, Calospatha, Plectocomia, Plectocomiopsis, Myrialepis, Zalaca, Pigafelta, Korthalsia, Metroxylon, Eugeissona. Ann R Bot Gard Calcutta 12(2):1–231
Blatter EJ (1926) Palms of British India and Ceylon. Oxford University Press, London
Brandis D (1874) Forest flora of north-west and central India. W.H. Allen & Co., London
Brandis D (1906) Indian trees (reprint). International Book Distributors, Dehradun
Brooks TM, Mittermeier RA, Mittermeier CG, da Fonseca GAB, Rylands AB, Konstant WR, Flick P, Pilgrim J, Oldfield S, Magin G, Hiltin-Taylor C (2002) Habitat loss and extinction in the hotspots of biodiversity. Conserv Biol 16:909–923
Ellis JL (1989) Plant diversity in the Andamans with emphasis on endangered and endemic species. In: Saldanha CJ (ed) Andaman, Nicobar and Lakshadweep. An environmental impact assessment. Oxford and IBH Publishing Co. Pvt. Ltd, New Delhi, pp 69–74
Govaerts R, Dransfield J (2005) World checklist of palms. Royal Botanic Gardens, Kew, Richmond, Surrey
Govaerts R, Dransfield J, Zona SF, Hodel DR, Henderson A (2006) World checklist of Arecaceae. The Board of Trustees of the Royal Botanic Gardens, Kew. http://www.kew.org/wcsp. Accessed 11 November 2006
Griffith W (1844–1845) Palms of British East India. Calcutta J Nat Hist 5:1–103
Henderson A (2009) Palms of southern Asia. Princeton University Press, Princeton
Hooker JD (1872–1897) Flora of British India, vol 1–7. L. Reeve and Co., London
Mathew SP, Abraham S (1994) The vanishing palms of the Andaman and Nicobar Islands, India. W.H. Allen & Co., London. Principes 38:100–104
Mathew SP, Krishnaraj MV, Mohandas A, Lakshminarasimhan P (2007) Korthalsia rogersii—a vanishing endemic palm of the Andaman and Nicobar Islands. Palms 50:43–47
Moore HE Jr (1979) Endangerment at the specific and generic levels in palms. Principes 23(2):47–64
Myers N, Mittermeier RA, Mittermeier CG, da Fonseca GAB, Kent J (2000) Biodiversity hotspots for conservation priorities. Nature 403:853–858
Official Report (2006) Andaman & Nicobar Islands post tsunami livelihood measures (compiled by Janak Digal development Commissioner, Andaman & Nicobar Administration)
Ojeda F, Arroyo J, Maronon T (1995) Biodiversity components and conservation of Mediterranean health lands in southern Spain. Biol Conserv 72:61–72
Parkinson CE (1923) A forest flora of the Andaman Islands. Government Press, Simla
Rao MKV (1986) A preliminary report on the angiosperms of Andaman & Nicobar Islands. J Econ Taxon Bot 8:107–184
Renuka C (1995) A manual of the rattans of Andaman and Nicobar Islands. Kerala Forest Research Institute, Peechi, Trichur, India
Renuka C (1999) Indian rattan distribution—an update. Indian For 125:591–598
Sasha Barrow (1998) A revision of Phoenix. Royal Botanic Gardens, Kew
Sharma SK, Bhat PM (1982) An assessment of cane potential of Baratang Island in south Andaman forest division. Indian For 108:270–282
Subbarao NV (1989) Fauna of Andaman and Nicobar Islands: diversity, endemism, endangered species and conservation strategies. In: Saldanha CJ (ed) Andaman, Nicobar and Lakshadweep. An environmental impact assessment. Oxford and IBH Publishing Co. Pvt. Ltd, New Delhi, pp 74–83
Thothathri K (1977) A review of the floristic studies in the Andaman & Nicobar Islands up to 1970. Bull Bot Surv India 19:127–131
Uhl NW, Dransfield J (1987) Genera Palmarum—classification of palms based on the work of H. E. Moore Jr., Bailey Hortorium and International Palm Society. Allen Press, Kansas
Woodruff DS (2010) Biogeography and conservation in Southeast Asia: how 2.7 million years of repeated environmental fluctuations affect today’s patterns and the future of the remaining refugial-phase biodiversity. Biodivers Conserv 19:919–941
Acknowledgments
Financial assistance from CSIR, New Delhi (Research Associate Fellowship to TNM) and Ministry of Environment & Forests, Govt. of India, New Delhi (AICOPTAX project to CR) is gratefully acknowledged. The authors sincerely thank the Director, Kerala Forest Research Institute, Peechi, for providing necessary facilities and encouragement for this study. Thanks are due to PCCF Andaman & Nicobar Islands for permission to study in different islands and to Smt. N. Kala, Conservator of Forest (HQ), Andaman & Nicobar Islands, for the logistic support. We are also grateful to the authorities of Forest Department, Andaman & Nicobar Administration, for the cooperation and timely help during explorations. Thanks are due to the Joint Director, BSI, Andaman for the permission to consult the herbaria. We thank Prof. G.R. Shivamurthy, Prof. C.R. Nagendran, and Prof. K.B Sadanand, Mysore, for constructive suggestions. Finally, we thank the editors and two anonymous reviewers for their comments.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Manohara, T.N., Linto, E.L. & Renuka, C. Diversity and conservation of palms in Andaman & Nicobar archipelago. Biodivers Conserv 19, 3655–3666 (2010). https://doi.org/10.1007/s10531-010-9918-6
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10531-010-9918-6