Duration : One Year
Funded By : Ministry of Environment and Forest, Govt. of India
Carried Out By : Nature Environment and Wildlife Society

Introduction:
As such the state has been richly endowed by nature in terms of great diversity of physical environment. From the Bay of Bengal to the snow-capped Himalaya through vast stretches of alluvial plains, the physiognomic diversity and a myriad of climatic situations have given rise to countless habitats across the length and breadth of the state. Further, West Bengal falls in the transition zone between peninsular Indian sub region, Indo-Malayan sub region of Oriental zone and Palaearctic region. These two rare attributes combindly provided West Bengal its great array of natural ecosystems embellished with the ingress, colonization and interspersion of life forms from all the adjoining regions. The richness is reflected by the fact that West Bengal though has only2-7 percent of the total land area of the country, but four out of ten recognized biogeographical zones India are represented in the state. As such the state harbours 23 percent vertebrate fauna and 10 percent invertebrate fauna (of the group recorded so far from the state) of India (Anon.2000). Further, the problem of human population explosion in the state has been aggravated due to huge immigration from East Pakistan now Bangladesh since 1947. The pressure of such an enlarge and impoverished population along with the urbanisation and industrial development have taken a heavy toll of natural area of the state through shrinkage and degradation. As a result, many ecosystems and floral-faunal species have become threatened. Unfortunately, while some of the megaspecies, such as Tiger (Panthera tigris), Elephant(Elephas maximus), Rhinoceros( Rhinoceros unicornis), Gaur (Bos frontalis), etc., have brought under regular monitoring programme as regard habitats and population size, many other equally important as well as threatened species are left uncared for. The present project has been taken to estimate the trend of population, area of concentration and other related aspects of seven species of vertebrates in West Bengal.

The seven species are:

1. The Himalayan Newt or Salamander, Tylototriton verrucosus (Amphibia: Caudata: Salamandroidae): Only species of salamander recorded from India. Within Indian limit, confined to in and around perennial as well as seasonal pools in the hilly pockets of Eastern Himalaya between 1260 and 2220m. altitudes. Included in Schedule II of IWPA (1972) AND CONSIDERED AS Endangered in RDB-Nat. (Anon.1994 a). 
   
   
   
2. Estuarine or Salt Water Crocodile, Crocodylus porosus (Reptilia: Crocodylia: Crocodylidae): Largest of existing crocodiles. Within the limit of West Bengal recorded only from the coast of Sundarbans. The skins and other body parts are of significant commercial importance in the international market. Kept in schedule I of IWPA (1972), Appendix I of CITES and treated as Endangered in RDB-Nat. (Anon.1994 a).
   
   
   
3. Olive Ridley Turtle, Lepidochelys olivacea (Reptilia: Testudines: Chelonidae): A species of marine turtle. Population has heavily suffered from accidental catch in fishing nets during breeding migration. In West Bengal, this turtle emerge for nesting in the coasts of Medinipore and the Sunderbans. Included in Schedule I of IWPA (1972), Appendix I of CITES and considered Endangered in RDB-Nat. (Anon.1994 a).
   
   
   
4. Bengal Florican, Houbaropsis bengalensis (Aves: Gruiiformes: Otididae): One of the most threatened species of Indian Avifauna. In West Bengal, it is recorded from some protected areas, particularly from Jaldapara Wildlife Sanctuary. Included in Schedule I of IWPA (1972), Appendix I of CITES and treated as Endangered in RDB-Nat. (Anon.1994 a).
   
   
   
5. Gangetic Dolphin, Platanista gangetica (Mammalia: Cetacea: Platanistidae): Only species of fresh water dolphins of the country occurs mainly in Ganga and Brahmaputra river systems. Protected under Schedule I of IWPA (1972), Appendix I of CITES and treated as Vulnerable in RDB-Nat. (Anon.l994a).
   
   
   
   
6. Indian Wolf, Canis lupus pallipes (Mammalia: Carnivora: Canidae): Widely distributed in the country with very much fragmented population. Reported as gradually getting foot hold in certain afforested areas of South West West Bengal. Kept in Schedule I of IWPA (1972) and Appendix I of CITES. Considered as Vulnerable in RDB-Nat. (Anon.1994).
   
    
   
   
7. Indian Pangolin, Manis crassicaudata (Mammalia: Pholidota: Manidae): Widely but sporadically reported from almost throughout the country. Included in Schedule I of IWPA (1972), Appendix II of CITES. Considered as Insufficiently known in RDB-Nat. (Anon.l994a).
   
    

Objectives:
To estimate the population trends of the above mentioned seven threatened and poorly known species of wildlife in West Bengal and to identify the areas of concentration.

Methodology:
There is no prescribed uniform methodology to estimate population trend of all the seven species selected. Because of difference in nature, habit and habitat of the seven species, methodology adopted has been differed from one to another . It has been felt that the direct study of all the seven species within a span of one year may not be sufficient to have a fruitful inference as regard the population trend of them. As much, indirect information have been gathered from various literature, animal monitoring books and diaries of management people specially of Forest Guards, Beat officers, Range Officers, Ban Sramik, members of EDC, FPC, NGO as well common villagers, fishermen, and others.

Inference:
From one year field study and information gathered through the local people as well as existing current literature on the population trend of seven species of vertebrates, following inference may be drawn.

•  Himalayan Salamander : Population of Himalayan Salamander has drastically gone down or even wiped out from many of its erstwhile habitats in Darjeeling district. Urbanisation, direct or indirect destruction of water bodies, tourist movement, over curiosity, extension of agricultural field particularly the practice of round the year cultivation are the major factors responsible for its population decline. Concretisation of embankment in Mirik Lake and Jore Pokhri (The Salamander Sanctuary) is the main reason for the declination of Salamander population in those areas. However, within a particular range of elevation, the species is still fairly abundant in and around the seasonal or perennial water bodies of very small to large sizes. Breeding populations with huge number of tadpole of various sizes are found during rains in almost all the water bodies of relatively undisturbed areas.

•  Olive Ridley Turtle : Seasonal migration of Olive Ridley Turtles for nesting in the coastal zone of West Bengal is a fairly old phenomenon. As per available records, number of migrating turtles, vary from one year to other. (Hejmadi 2001) As such, number of turtle nest or incidental catch in a particular year should not be taken as indicator of overall population increase or decline. However, various factors responsible for the decline in the population or disturbance in nesting, such as mortality due to incidental catch, illegal trade of turtle meat, erosion and flood in nesting beach, frequent cyclone, mass scale use of unregulated shooting nets of small-mesh sizes for the collection of tiger prawn seeds, pollution from industries along the river Hooghly and destruction of surface-living marine animals, construction in the upper reaches and erection of dykes in lower reaches of Hoogly estuary etc. are still operating. As such though the present study could not establish a particular trend of the over all migrating population of Olive Ridley Turtle in the West Bengal coast, but unless the existing negative factors are properly addressed there may be definite decline in the near future.

•  Estuarine Crocodile : From the frequency of sightings of Estuarine Crocodile in the river systems of the Sunderban and the increased incidence of their attack on human beings, it may be derived that the population of them is now fairly established. Existing increased trend in population may be attribute to the success of Central Crocodile Breeding and Management Project, 1975 and subsequent release of young animals from Crocodile Rearing Centre at Bhagabatpur since 1979. Occurrence of smaller ones or yearlings in the river system of Sunderban is the most positive sign towards building up of a natural population. As the specimens relased from captive breeding centre are now breeding successfully in the wild, it is necessary to monitor the further release of specimen. As Estuarine Crocodile is a voracious predator species, its population must be limited within the carrying capacity to prevent any ecological imbalance in the Mangrove ecosystems.

•  Bengal Florican : Rahmani et al. (1991) estimated ten specimens of Bengal Florican from Jaldapara Wildlife Sanctuary. Further, occasional reports of its sightings in the recent past from different parts of North Bengal are available. However, during block count in different sample plots located mostly in the area of its recent sightings could not find any specimen. It is, to be noted that vast stretch of riverine grassland, the ideal habitats for Bengal Florican, are still widely distributed particularly in the Buxa Tiger Reserve, Jaldapara Wildlife Sanctuary and Gorumara National Park. Most of these habitats are practically free from any hunting or other anthropogenic pressures. As such, there is no apparent reason of non-existence of this bird in North Bengal. Discovery of any remnant populations and proper management of the same may help in building up of an well-established population of Bengal Florican in its natural habitat of North Bengal. For habitat management with special reference to Bengal Florican two natural threats are to be property addressed. These are frequent changes in the course of rivers and occasional flash floods resulting huge damage to the exisisting grass land systems and the population of the Bengal Florican living there.

•  Indian Wolf : Available direct and indirect evidences clearly indicate populations of the Indian Wolf is gradually building up in the many patches of afforested tracks of south west West Bengal. It appears that present population of the Indian Wolf in the State is actually dispersed from neighbouring States of Jharkhand and probably Orissa and found an alternative refuge in the newly grown forested areas in West Bengal. However, population of natural prey species of wolf has not yet been developed in the forest. As such, present populations of wolf though found shelter in the forest but depend mainly on the domestic stock for subsistence resulting apathy and man-wolf conflict. The population is still meager, very much scattered and may not be considered as viable as there is no pack formation. Introduction of various prey species along with awareness programme may provide viability to the wolf population of West Bengal.

•  Indian Pangolin : No estimate about the density of the Indian Pangolin could be made. Systematic survey in the protected areas as well as different forest villages could detect only three specimens. Estimation of the population based on the no. of specimens observed and the area surveyed will apparently yield a very gloomy picture. However, analysis of the sighting, records during last few years by the different sections of people as well as indirect evidence obtained during present surveys indicate its extent of occurrence and area of occupancy in the State as fairly high being more than 20,000 sq. km and 2000 sq . km. respectively. At the same time it is to be noted that except general management of conservation areas, no specific programme or care has been developed to protect this unique creature in the State Common apathy of the people, trade of scales, ritual hunting festival, and extension of agrarian economy and random use of pesticides making the species vulnerable.

•  Gangetic Dolphin : As per categories fixed, population of the Gangetic Dolphin may be considered as "Abundant" in Haldi River. Appearance of this species in lower stretches of river Hoogly has been explained as seasonal migration (Gupta 1986). As such, occurrence of stable and permanent population of Gangetic Dolphin in the estuarine water of the Sunderban is rather improbable. During the present surveys, surfacing of Dolphin was frequently observed in the river system of Sunderban. All the specimens who surfaced near the boat were of Irrawady Dolphins. Species- specific identification of those which surfaced little away from the boat was not possible. It appears that if the Gangetic Dolphin at all occurs in Sunderban, then the population should be considered as few, while the other Dolphin species i.e. Irawaddy Dolphin is the most predominant. Seasonal migration of Dolphin in the rivers of Sunderban might have been disturbed and declined due to large scale destruction of biomass during prawn seed collection and resultant reduction of its food species. Increased salinity of Sunderban rivers due to construction of dams at the upper reaches probably acting as another factor in the decline of migration rate. However, before drawing any definite conclusion about the occurrence of the population of Gangetic Dolphin in Sunderban, further surveys to be undertaken.