ANDAMAN & NICOBAR ISLANDS – ENDEMIC DIVERSITY

Dr. T. Sundaramoorthy

Nature has endowed these lands with a unique and varied plant and animal life both on land and sea.

The Andaman and Nicobar Islands are globally known because of their scenic beauty and rich biodiversity. The species richness with high degree of endemism is attributed to the geological situation with three natural ecosystems, viz., tropical forests, mangroves and coral reefs. Apart from the endemism, many species found in these islands have an evolutionary and ecological linkage to Indian, Myanmarese and Malaysian origins.

Species richness and endemism of plants and animals in the A & N Islands
Species Total no. of species No. of endemic species % of endemics
Plants 2649 314 13
animals 8386 1117 13.31

Source: Mathew (2017); Zoological Survey of India (2013).

The present forest cover is about 87 percentage of the total area. Of the 8386 animal species, 2649 species are endemic to the islands. Most of these endemic species are either threatened or endangered, and in some cases the status is not known.

 Mammals

Of the fifty-eight species of mammals found, thirty- six species are endemic to the islands. According to IUCN, about five endemic species of mammals are threatened.

 The role played by the island organisms, over the years, in the evolutionary process is so significant that conservation of the fragile island biological resources is important not only for maintaining the ecological heritage but also for human utility.

Of the thirty-six endemic species of mammals, the crab eating macaque is found only in three islands of the Nicobar group. It is found in the tropical    rain forests and can be sighted along the coastal areas. It eats wild fruits, banana, papaya, etc. However, the crab eating behavior of this species is yet to be ascertained. There are four species of tree shrews found in these islands, of which three are listed in the IUCN threatened list.

The Andaman masked palm civet is found only in the Andaman Islands. It is an arboreal and omnivorous species feeding on fruits and small invertebrates.

Two subspecies of wild pigs are found in these islands, one each in the Andaman and Nicobar group of islands. Both these species inhabit the adjoining forests and frequent the cultivated areas in search of food. In so doing, they become easy prey to the local tribals who relish its meat.

Twenty-six species and subspecies of bats are found in these islands, of which six each are endemic to the Andaman and Nicobar Islands.

Threatened mammals of Andaman and Nicobar Islands
Common name Scientific name
Andaman Island Spiny Shrew Crocidura hispida*
Millers Andaman Spiny Shrew Crocidura andamanensis*
Jenkins Andaman Spiny Shrew Crocidura jenkinsi*
South Andaman Horse Shoe Bat Rhinolophus cognatus*
Rat Rattus stoicus*

*These species are limited to this eco-region.

Birds

Two hundred and seventy species and subspecies of birds, including one hundred and six endemic species have been recorded from these islands. Out of these one hundred and six endemic species, thirteen species are accorded the status of being threatened. A few important endemic species are described below.

The Narcondum hornbill is small in size and found only in the tiny island of Narcondum. It is found in small flocks and feeds mainly on fruits. The population of this bird is about 200.

The Nicobar megapode, also called Nicobar Scrubfowl, is found in the tropical moist dense forests along the coastal areas of Nicobar Islands.  Its breeding habit is atypical and highly significant. The eggs are incubated in mounds made out of sand and dry vegetation, unlike other birds that incubate their hatchlings.

The Andaman hawk owl is found commonly in the mangrove swamps, creeks and lagoons all over the Islands and feeds predominantly on insects.

The Andaman drongo, commonly found in forested areas of Andaman Islands is a gregarious bird and feeds on winged insects.

Common name Scientific name
Andaman serpent-eagle Spilornis elgini*
Andaman crake Rallina canningi*
Andaman wood-pigeon Columba palumboides
Andaman cuckoo-dove Macropugia rufipennis
Andaman coucal Centropus andamanensis*
Andaman scops-owl Otus balli*
Andaman hawk-owl Ninox affinis
Narcondam hornbill Aceros narcondami*
Andaman woodpecker Dryocopus hodgei*
Andaman drongo Dicrurus andamanensis*
Andaman treepie Dendrocitta bayleyi*
White-headed starling Sturnus erythropygius

*These species are limited to this eco-region.

Reptiles

Seventy-seven species and subspecies of reptiles, including four species of turtles, one species of crocodile, forty species of snakes and thirty-two species of lizards have been recorded from these islands. Of these, twenty-four species are endemic to these Islands. Among them, thirteen species of snakes and ten species of lizards form the majority. A few important endemic species include Andaman cobra, Andaman cat snake, Smith’s cat snake, Boie’s cat  snake,  brown  wolf  snake,  Biswas’s  wolf  snake, Andaman banded kukri, Andaman water monitor, Andaman day gecko, green forest lizard, Andaman garden lizard, Tiwari’s garden lizard, Andaman skink, etc.

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Amphibians

Amphibians of these islands have not been explored and documented properly. However, about eighteen species and subspecies of amphibians have been recorded. Of these, five species are endemic to these islands. The important endemic species include brown frog and Nicobar frog.

Fish

Fish of these islands include eight hundred and twenty and eighteen species and subspecies of marine and inland fish respectively. Of these, only two marine species are endemic to these islands.

Insects

Insects of these islands include two thousand two hundred and fifty six species and subspecies. Of these, four hundred and eighty five species are endemic to these islands. With about two hundred and twenty five species, the Andaman & Nicobar Islands house some of the larger and most spectacular butterflies of the world. Of these, ten species are endemic to these islands.

The role played by the island organisms, over the years, in the evolutionary process is so significant that conservation of the fragile island biological resources is important not only for maintaining the ecological heritage but also for human utility.

Source:

Eco News, Vol 9, No 4, January to March, 2004.

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