Great Nicobar Research Articles

Hydrogeology of southeastern coastal parts of Great Nicobar Island, India: development of an integrated conceptual model for a hitherto unexplored island in the Indian Ocean

The vulnerability of oceanic islands in the face of climate change, vis-a-vis human development, is a serious issue at present. The island of Great Nicobar in the Nicobar archipelago in the Indian Ocean will face major challenges owing to its impending development activities. The eastern coastal part of the island was investigated through exploratory drilling, geophysical investigations, and water-table monitoring. Field investigations show that coralline sand is the major groundwater repository and is commonly developed through dug wells. Exploratory drilling down to 100 m depth revealed that the underlying Tertiary consolidated aquifer is of limited potential and showed increased salinity with depth. Water is also present along the contacts of shale–sandstone. The mean seasonal fluctuations in the depth to the water table was 0.18 m. Geoelectrical sections identified promising fresh groundwater zones along the east coast, with freshwater-bearing semi-weathered coralline limestone and coralline sand having a resistivity of 146–622 ohm m. Based on generated data, a 3D model of the aquifer system was constructed. The observed soil infiltration rate was 0.3–0.5 cm h −1 . The specific capacity of the dug wells was c . 5 m 2 min −1 . The permeability of the phreatic aquifer was 5–11 m/day and the transmissivity was 0.11–0.2 m 2 min −1 . The optimum yield of the unconfined aquifer was 17–21 m 3 /day. The tidal influences on the aquifer system also added complexity to the island's hydrogeological dynamics. Despite the challenges of restricted access due to the presence of aboriginal tribes in the island, the present study provides the maiden set of hydrogeological data for the island, revealing the disposition of the aquifers, their properties and their spatio-temporal behaviour.

All eyes on the island - A book review of The Great Nicobar Betrayal

All eyes on the island - A book review of The Great Nicobar Betrayal

Activity budget and habitat use in the Nicobar long-tailed macaque Macaca fascicularis umbrosus

Time-activity budget and pattern of habitat use are basic tools to understand an animal’s interaction with its environment. We studied a primarily commensal group of long-tailed macaques (Macaca fascicularis umbrosus) with 22 individuals in the Great Nicobar Island of India at Campbell Bay. Data on the frequency and duration of different activities were collected through scan sampling and ad libitum notes. We recorded the geo-coordinates of the visually approximated group center using a handheld GPS receiver (Garmin GPS Map 76csx) every 30 min to assess the ranging patterns. The group spent more time resting, followed by feeding, social behaviours, movement, foraging, and scouting. The time spent on various activities did not vary at different times of the day and showed no seasonal variations. The macaques fed mostly on the cultivated fruits. Although the total home range size was 66ha, the most frequently used area was only 6 ha. The macaques ranged over a larger area in the dry season than in the wet season. All these patterns show that the behaviour of the study group was typical of that of the commensal macaques of other species.

On a Collection of Mosses from Great Nicobar Island

On a Collection of Mosses from Great Nicobar Island

Additions to the Indian' Flora from Great Nicobar Island

The paper presents 10 plant species from the Great Nicobar Island which are additions to the Indian flora.

New or Little Known Plants from Great Nicobar Island

This paper describes two new species, Tinomiscium nicobaricum (Menispermaceae) and Ophiorrhiza infundibularis (Rubiaceae) with illustrations and fifteen new records of various Pteridophytes and Angiosperms as additions to Flora of India. Dendrobium pensile (Orchidaceae), a new record for India is also illustrated.

New Records of Malesian Plants from Great Nicobar Island

No Abstract.

Botanical Results of the Joint Scientific Expedition to the Great Nicobar Island

The results of an extensive and intensive botanical exploration, conducted in the Great Nicobar Island during a Joint Scientific Expedition in 1966 are summarised in this paper. Notes on the topography, geology, soil and climate are given. The vegetation and flora are dealt under (1) Mangrove forat, (2) Beach forest, (3) Littoral forest, (4)Tropical Evergreen forest and (5) Riverine vegetation. An enumeration of plants, collected during the expedition is appended. Notes on plants of economic importance are given at the end.

<I>Ophioglossum pendulum</I> Linn. (Ophioglossaceae)-a Rare and Interesting Plant from Great Nicobar Island

Ophioglossum pendulum Linn., a rare and interesting plant, collected by the authors from the Great Nicobar Island during a Joint Scientific Expedition in 1966 constitutes a new record fear India. The doubt that existed among the earlier workers about its possible occurrence in India has been cleared after a critical review.

Review of the subtribe Spinariina van Achterberg (Hymenoptera: Braconidae: Rogadinae) from India with description of one new species.

The Indian members of the subtribe Spinariina van Achterberg, 1988 are reviewed and a key to Indian species is provided. Spinaria westwoodi Cameron, 1906 is reported from Great Nicobar island and a new species, Spinaria indica Gupta & van Achterberg, sp. nov. from Nagaland, is described and illustrated. In addition, Batotheca nigriceps (Cameron, 1897) is reported from caterpillars feeding on Psidium guajava L. and S. spinator (Gurin-Mneville, 1830) from slug caterpillar (Limacodidae) on Elaeodendron glaucum (Rottb.) Pers. in southern India.

Survey of the present health & nutritional status of Shompen tribe of Great Nicobar Island.

Shompens are one of the two mongoloid tribes of Nicobar district. There is little information about their recent health status since the last survey which was conducted in 1998. Hence, a comprehensive health and nutritional survey was conducted in March 2017 to assess the changes. The survey was carried out by a joint team of various organizations including the ICMR-Regional Medical Research Centre and Tribal Welfare and Health Department both located in Port Blair. A detailed health and nutrition survey of the Shompen community was planned by deputing a field research team. The survey included demographic data, anthropometric data, clinical examination, screening for the markers of infectious diseases, respiratory pathogens, tuberculosis and haemoglobinopathies. About half of the Shompen adults (both males and females) had a body mass index (BMI) of ≥23. However, Shompen children had a good nutritional status with no child suffering from undernutrition. As per BMI for age, none of the children <5 yr were under-nourished, while in the 5-17 yr group, 12 per cent of children were undernourished. Anaemia prevalence was about 48.3 per cent, with 54 per cent prevalence in females and 43.8 per cent in males. Fungal infection of the skin, acute respiratory infection and abdominal pain were the common morbidities observed. None had active pulmonary tuberculosis. Of 38 Shompens screened for IgG (immunoglobulin G) antibodies, 42.1 and 18.4 per cent were positive for measles and rubella, respectively. Seroprevalence of Leptospira was 35.5 per cent. The prevalence of hypertension was 13.2 per cent, whereas another 28.9 per cent were pre-hypertensive. The population structure of the Shompen is not skewed and under nutrition was not widely prevalent among the children of <5 yr. The other positive observations were the absence of malaria, filariasis and dengue. However, there was natural infection of measles and rubella. Fungal skin infection and intestinal parasitic infestations were widely prevalent. Although cardiovascular risk profile was low, there were signs of emerging risk of over-weight, hypertension and dyslipidaemia. These together with the high prevalence of smokeless tobacco use may have a serious effect on the cardiovascular disease susceptibility of the Shompen population in the future.

Occurrence record and range extension of Pomadasys andamanensis McKay &amp; Satapoomin, 1994 (Heamulidae: Haemulinae) from Great Nicobar Island, India

Present study reports the occurrence of Andaman grunt, Pomadasys andamanensis McKay &amp; Satapoomin, 1994 for the first time from Indian waters based on one specimen (standard length 156.27 mm) collected from Great Nicobar Island, Andaman and Nicobar Island. This finding represents a new addition to the grunt fish fauna of Andaman and Nicobar Island, India. The species is distinguished from its congeners by having four separated longitudinal black stripes on the dorsal half of the body. The detailed morphological features of P. andamanensis are provided and compared with its previous records. Description and figures of the species are provided herewith along the morphometric measurements and meristic counts.

Preliminary appraisal of deformation structures from Great Nicobar Island, Andaman-Sumatra arc system

The Andaman and Nicobar Group of Islands represent a topographic high of forearc sediments in an actively rising accretionary prism on the Andaman subduction margin. Preliminary observations of deformation structures recorded in tuff are reported from Great Nicobar Island. Active compression led to the formation of meso-scale deformation structures such as a schuppen zone with horse units; sole and roof thrusts; fault breccia zone; high angle reverse faults and pop-up structures. Offset of tuff beds up to a few centimetres are observed across these faults.

On the discovery of new sub-populations of &lt;i&gt;Bentinckia nicobarica&lt;/i&gt; (Kurz) Becc. (Arecaceae) in Andaman Islands,India: Mapping and updated red list assessment

Bentinckia nicobarica (Kurz) Becc., a threatened palm is known to be strictly endemic to the Nicobar group of Islands as per IUCN Red list assessment 1998. It grows in the lowland rainforests close to the coastlines and fairly distributed all over in Nicobar group of Islands except Great Nicobar. Recently, new natural sub-populations of this species have been discovered from Alexandra Island, Boat Island, Hopeday Island, Redskin Island, Tarmugli Island and coast of Wandoor, South Andaman. The IUCN guideline has been used for the reassessment of its threat status which will help in prioritizing conservation.

Predation of the Nicobar Shrew Crocidura nicobarica by a Cattle Egret Bubulcus ibis

The Nicobar Shrew Crocidura nicobarica (Miller, 1902) is an endemic and ‘Critically Endangered’ species restricted to Great Nicobar Island in the Andaman Sea, India. Predation instance on the Nicobar Shrew by a Cattle Egret is reported herewith for the first time in the littoral forests near Govind Nagar, Great Nicobar Island.

Genetic Characterization and Insular Habitat Enveloping of Endangered Leaf-Nosed Bat, Hipposideros nicobarulae (Mammalia: Chiroptera) in India: Phylogenetic Inference and Conservation Implication.

The Nicobar leaf-nosed Bat (Hipposideros nicobarulae) was described in the early 20th century; however, its systematic classification has been debated for over 100 years. This endangered and endemic species has achieved species status through morphological data in the last 10 years. However, the genetic information and phylogenetic relationships of H. nicobarulae remain neglected. The generated mitochondrial cytochrome b gene (mtCytb) sequences (438 bp) of H. nicobarulae contains 53.42-53.65% AT composition and 1.82% variable sites. The studied species, H. nicobarulae maintains an 8.1% to 22.6% genetic distance from other Hipposideros species. The genetic divergence estimated in this study is congruent with the concept of gene speciation in bats. The Bayesian and Maximum-Likelihood phylogenies clearly discriminated all Hipposideros species and showed a sister relationship between H. nicobarulae and H. cf. antricola. Current mtCytb-based investigations of H. nicobarulae have confirmed the species status at the molecular level. Further, the MaxEnt-based species distribution modelling illustrates the most suitable habitat of H. nicobarulae (294 km2), of which the majority (171 km2) is located on Great Nicobar Island. The present study suggests rigorous sampling across the range, taxonomic coverage, the generation of multiple molecular markers (mitochondrial and nuclear), as well as more ecological information, which will help in understanding population genetic structure, habitat suitability, and the implementation of appropriate conservation action plans for H. nicobarulae and other Hipposideros species.

A new species of Psaphis Walker (Zygaenidae: Chalcosiinae) from India

A new species, Psaphis gerhardi N. Singh, Ahmad & Joshi, sp. nov. is described and illustrated from the Great Nicobar Island, India. The new species represents the second species of Psaphis Walker, 1854 from India and also the first record of the genus from Nicobar Islands. Apart from this a checklist of the known species of the genus is also provided.

Holothurian spatial variability and substratum preference in the intertidal habitats of the Andaman Sea

Holothurians in the Indian waters are protected under the Wildlife (Protection) Act, 1972, yet poaching still threatens several species. Understanding species population and distribution trends is crucial to developing holothurian conservation and management directives. We examined the spatial variability in holothurian species assemblages from four intertidal habitats in the South Andaman (Burmanallah, Shaheed Dweep) and Great Nicobar Islands (B-Quarry, Shastri Nagar), India. Using multivariate statistical tools, we established trends between biological variables (Holothuroidea species) and environmental predictors viz., substratum, vegetation, pH, Sea Surface Temperature (SST), salinity, and water depth. We profiled the substratum into five types viz., dead coral with algae, sand, rock, rubble, and live coral. Seagrass and macroalgal cover contributed to the habitat vegetation. We documented five holothurian species in the present study and observed the most diverse assemblage at Shaheed Dweep, South Andaman (H’ = 0.9936; D = 0.4058). The overall relative species abundance was the highest for Shaheed Dweep (104 ind. 200 m−2), followed by Burmanallah (36 ind. 200 m−2), Shastri Nagar (26 ind. 200 m−2), and B-quarry (3 ind. 200 m−2). Species abundance positively correlated with water depth and SST. Principal component analysis (PC1 39.2% and PC2 23.8%) combined with Bray–Curtis cluster analysis revealed significant spatial variability in the holothurian assemblages. Substratum type, vegetation, and micro-habitat availability limited species distribution and abundance. The present study suggests species distribution and abundance be a function of habitat heterogeneity and water depth from the sampled regions.

Contribution to the Erebidae fauna of the Great Nicobar Island, India with description of two new species (Lepidoptera: Noctuoidea).

In the present paper, we describe two new species, Garudinia shompen sp. nov. (Arctiinae) and Plusiodonta nicobarensis sp. nov. (Calpinae) and report five new species records for India: Nishada sambara (Moore, 1859), Teulisna chiloides Walker, 1862 (Arctiinae), Tamba cosmoloma Prout, 1928, T. occidinawa Holloway, 2005 (Boletobiinae) and Anoba rigida (Swinhoe, 1895) (Anobinae), collected from the Great Nicobar Island. Except Garudinia, all the other taxa studied herein are documented for the first time from the Great Nicobar Island. Detailed description of new species, diagnoses of all the included species with similar congeners along with habitus images and genitalia illustrations and their distributional notes are provided.

Range extension and re-recording of Redigobius bikolanus (Herre, 1927) from Great Nicobar, India

Redigobius is a genus of goby fish belonging to order Gobiiformes. Redigobius is currently represented by 15 species worldwide of which Redigobius bikolanus is a widespread species. This species was recorded previously from Middle Andaman Island in 2002. There was not a single evidence of the species after that time, from Indian region. Recently, during a faunal survey in great Nicobar Island resulted in collection of a R. bikolanus for the first time and proving evidence for range extension of the same from Nicobar group of Islands. The species was collected from one of the estuarine creeks of Great Nicobar island. Details of the morphological data, live colouration and wild habitat are provided for the new record.