Endangered
Monitoring Tigers in the Twenty-First Century India-Part V
-Vinod Rishi
Here is the fifth part of an article published by Shri Vinod Rishi in
The Indian Forester. Vol.136:10. Wild Life Special.
Shri Vinod Rishi is IFS – retd. and a Former Additional Director General of Forests (Wildlife), Govt. of India; E-mail: vinodrishi@rediffemail.com
(B). Application of Field Methods in Census and Research Work
The two field methods to which the field officers who had worked under Project Tiger were exposed used tiger pug marks: one used it as an index for ascertaining individual tiger’s territorial occupancy; and the other, tiger’s identity for estimating tiger populations
in a given area. Over the years the distinction between the two has been mislaid by the current generation of field officers and research scholars, who treat the two methods to be one and the same. A controversy generated by a review of the field censuses
in 1987 killed both methods. The review of the field censuses declared that the field methods using tiger pug marks as a basic index for estimation of tiger populations are unreliable, and give unrealistic and unreliable results (Karanth, 1987, 2003; Day,
Undated; Banks Undated).
(B.I.) The Controversy: Pug marks are not a reliable census index – field methods using pugmarks are defective (Karanth, 1987).
The review of the data from field censuses (Karanth, 1987)
(a). Growth Rates, Density and Biomass of Tiger Populations
Table– 2
Tiger population over the years
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Sites
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1972
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1979
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1984
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1989
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1993
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1995
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1997
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2001-02
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Tiger Reserves
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268
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711
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1,121
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1,327
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1,366
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1,333
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1,498
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1,576
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Outside Tiger Reserves
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1,559
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2,304
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2,884
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3,007
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2,384
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2,010
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2,066
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Total
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1,827
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3,015
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4.005
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4,334
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3,750
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3,508
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3,642
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Compilation based on the periodic reports of ProjectTiger Directorate, Govt. of India.
After analyzing the data from the tiger census figures for 1972 and 1984, and using the information from the research work of some wildlife research scholars in and outside India, the review concluded:
i. Between 1972 and 1984, the census figures show phenomenal growth in tiger numbers over the years in almost all parts of the country:
The Indian tiger population had more than doubled: from 1,827 in 1972 to 4,005 in 1984. There was an exponential increase in the growth of tiger populations in 11 (sic) original Project Tiger Reserves and 14 States of India. Even relatively poor tiger habitats
like Bandipur showed high growth rate of 14%, per annum for over 12 years in succession. The research studies by Schaller in Kanha National Park, Sunquist and Smith in Chitwan National Park and Chitwan Region in Nepal indicate that the growth rates of tiger
populations in excess of 6% were abnormal.
ii. The 1984 census data indicated excessive densities and biomass reached by tigers in Indian tiger reserves.
a. The density of tigers recorded in the research studies by Schaller, Sunquist and Smith in the tiger habitats in Kanha in India, and Chitwan in Nepal, showed that in well protected habitats tigers may reach densities that range between 17 km2 to 11 km2
per tiger; Overall, the densities in Indian tiger reserves ranged between 54.84 km2 per tiger in the Indravathi tiger reserve, and 5.97 km2 per tiger in the Corbett tiger reserve in 1984; The census figures showed that 6 out of 18 tiger reserves, namely, Corbett,
Bandhavgarh, Dudhwa, Sunderbans, Kanha, and Ranthambhore tiger reserves, had tiger densities that ranged between 10.89 and 5.79 km2 per tiger, which exceeded the stipulated range.
b. The tiger biomass in the above mentioned 6 tiger reserves – the Corbett, Bandhavgarh, Dudhwa, Sunderbans, Kanha, and Ranthambhore tiger reserves – exceeded 10 kg/ km2 whereas a really superior habitat can only support a tiger biomass of 7 to 10kg/km2.
Overall, the tiger biomass in the tiger reserves in India ranged between a low of 2.08 kg/ km2 in the Indravathi tiger reserve and a high of 19.58 kg/ km2 in the Corbett tiger reserve.
-To be Continued
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