Rhino Conservation

The armoured truck of the jungle, the Asian Rhinoceros is the largest and most powerful animal on land with the exception of the Elephant. It is usually about nine feet in length, and this is also nearly the girth of its body. The rhinoceros is a quiet and inoffensive animal, but when attacked or provoked it becomes livid and dangerous and he is even sometimes subject to paroxysms of fury, which nothing can ease.

All three Asiatic species of rhinos were found in different parts of West Bengal. The smaller one-horned or the Javan Rhinoceros (Rhinoceros sondaicus Desmarest) was found in the Sunderban mangrove forests about a century back and was extinct by 1900. The Asiatic two-horned or Sumatran Rhinoceros (Didermocerus sumatrensis Fisher) was found in the plains of North Bengal till about 1930. The Great Indian One-horned Rhinoceros (Rhinoceros unicornis Linnaeus) is known to have once been extremely common and widespread in the Indo-Gengetic plains of the north, central and south-eastern part of the state. By the end of the 17th century it had completely disappeared from much of the range.

Rhinos have been killed for the horn, which is wrongly believed to have aphrodisiac properties. Poachers killed 28 rhinos during the period 1968-72. Intense anti-poaching measures reduced the killing spree, but there have been occasional spurts. During 1981-85, poachers killed 9 rhinos. However, poaching has been contained and only 3 cases were recorded during 1994-98. Habitat shrinkages has also led to population loss. This is caused by floods, invasion of grasslands by woody species and pernicious weeds and incendiary fires.

Anti-poaching measures have been intensified by regular patrolling, constitution of special protection for strengthening communication networks, provision of better arms for staff, coordination of law enforcement agencies, incentives and rewards, publicity/nature education/awareness generation and eco-development activities for fringe villages. Habitat improvement

works are initiated by canopy manipulation in woodlands with planting of indigenous fodder grasses, weed eradication, control burning and fire control, grazing control of domestic livestock and flood embankment protection works and soil moisture conservation works.

Conservation biologists are charged with elucidating the factors affecting the persistence and evolutionary potential of populations. It has now been well illustrated that environmental heterogeneity and migration can maintain genetic variability in natural populations. The fragmentation of habitats by human activities, however, often prevents migrations and genetic exchange among populations. As a consequence, local population become isolated and cause "inbreeding".

Inbreeding and the resulting loss of the genetic variability are often inevitable consequences of the severe reduction in population size experienced by endangered species, but the extent to which this results in inbreeding depression is likely to vary tremendously and is difficult to document in wild population. The population may, finally, become highly endangered through the loss of genetic adaptability.

Nevertheless, a primary goal of conservation efforts has been to preserve a maximum amount of genetic variation in each species. The Wildlife Wing of the Govt. of West Bengal in collaboration with the Wildlife Institute of India, Dehradun and the National Institute of Immunology,New Delhi, therefore, undertook a study for genetic finger-printing of rhino population distributed within this state.

The surviving population in West Bengal in two pockets have become isolated since no habitat corridor exists between these two Protected Areas. The absence of any likelihood of

infusion of the newer genetic materials into the already confined gene pool, insurmountable biotic pressure and ever-growing habitat encroachment have become cause of concern.

In view of this precarious scenario, information on the genetic diversity is needed to address issues related to management and conservation of this highly endangered species. In order to gain an insight into the organisational aspects of the genome, a study on the DNA sequence variability within and between the rhino species was undertaken. It is envisaged that a detailed understanding on genetic variability would greatly facilitate the effective conservation of this species. The resultant information would also enable to compare rhino genomes from Gorumara and Jaldapara and later even from other parts of the world. The purpose of the present study was to establish the pattern and extent of genetic variation at the DNA sequence level among the rhino population in West Bengal using conventional DNA profiling and AP-PCR mediated approaches. Further, it was aimed to develop species specific DNA probe so that the same may be used for ascertaining the origin of tissues, bone or horn samples in forensic or poaching cases. Important conclusions drawn from the present preliminary genetic study wherein the collection of blood and tissue samples through chemical immobilaztion ans skin biopsy technique were integral and inevitable are stated below:

The chemical immobilization of two captive and six free ranging Rhinos was successfully carried out. The combination of etorphine and acepromazine maleate(Immoblion) is a drug choice since it has a wide safety margin, short induction time and rapid reversibility. Each animal immobilized was photographed, hence a complete set of sequential pictures on chemical immobilization and animal handling is now available. This is one of the significant outcome of the study and would have immense educational and training utility.

Well demonstrated skin biopsy technique on other free ranging animals including the Asian Wild Buffalo in Assam did not work on Rhinos in spite of few trials were made, both on captive as well as wild animals. In each trial the dart bounced off without collecting the samples and dart got distorted. Hence, the technique needs further experimental trials and refinement of the biopsy dart since this technique can be of great help where immobilization of endangered animals is difficult, tedious and also risky.

Aware of the fact that the sample size was very small and limited only to one PA in West Bengal, it is difficult to conclusively demonstrate a clear picture about the genetic status of Rhinos in West Bengal and their relationships with other populations. However, the preliminary findings revealed high level of genetic homogeneity in the Rhino population though several approaches were used simultaneously. At this juncture, it is not possible to corroborate actual situation of the inbreeding depressi

With respect to effective management and conservation of Rhinoceros unicornis in the two PAs in West Bengal, it becomes necessary to supplement wild or captive populations with individuals from a different conservation unit in order to avoid likely inbreeding depression. The appropriate strategies would required to be evolved for infusion of genetic materials into the confined gene pool.