Monitoring Tigers in the Twenty-First Century India-Part VIII
Here is the eighth 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;
(Continued from last month)
ii. Error In Setting Standards For
Comparing Population Parameters In Different Ecosystems
a. The standards used for comparison of densities and biomass between ecologically different tiger conservation units were not scientifically robust and valid. The dissimilarity in the basic structure of the ecosystems, quality and quantity of
productivity of resources that contribute to the growth and secure persistence of tiger populations in an area come in the way of making scientific comparisons among dissimilar ecosystems.
To illustrate: Research studies had shown that tigers preferred riverine forests and grassland habitats in Chitwan region (Sunquist, 1979). Because of their bio-geographical consonance and similar ecosystems the results from studies carried out in Chitwan in
Nepal may be applicable to Dudhwa tiger reserve in India, and those carried out in a part of Kanha National Park to the rest of Kanha tiger reserve; but they are not applicable to the bio-geographically and ecologically different tide-affected mangrove swamps
of Sunderbans because of their systemic differences, because they do not have riverine forests and grasslands, and the continuous rise and fall of tides inundate and drain out tidal water from the tiger’s habitat. Tiger habitat is in perpetual flux; the land
surface is perpetually expanding and contracting due to the tidal rhythms; the tigers’ prefer to rest and breed in the extensive stretches of Phoenix paludosa on higher land. There is no ecological consonance among the Terai, central Indian plateau forests,
Sunderbans, and other tiger habitats situated in different landscapes and bio-geographical zones and biomes. For applying a common yard-stick to all one has to first establish its validity.
In many tiger reserves, cattle biomass is a significant addition to the prey base of tigers, and it contributes to the growth of tigers. Contrary to the assertion made in the review, that all cattle-kills are reported in India because compensation is paid for
them, the facts are different. The carcasses of cattle killed are often not available to establish the claim for compensation, the compensation amount is too meager, and the process to claim it too cumbersome. For this reason quite a good number of kills miss
getting recorded in the books. The situation in 1970s and 1980s was even worse. The indeterminate nature of this addition also cannot be ignored.
Therefore, the wide variation in tiger densities and tiger biomass shown in the census results of 1984 in India cannot simply be explained away by supposed difference in protection standards or errors in census methodology, without eliminating the effect of
divergent inputs in ecological productivity of resources affecting the growth of tigers in these habitats.
b. Historical records also
do not support the assumed rigor of 11 km2 to 17 km2 per tiger for universal application as a standard range of densities a good habitat can attain. Tiger hunting bags recorded by different hunters in the past contradict such assumptions. “In quiet jungles
of north ASSAM, where game was plentiful and men scarce and tigers suffered a minimum of persecution, Hanley found that ten or twelve tigers were often in the same jungle block of twenty or thirty square miles…” (Imam, 1970). It is equivalent to a minimum
of ten tigers in thirty square mile and a maximum of 12 tigers in 20 square miles, corresponding to densities of 7.5 km2 per tiger to 4.12 km2 per tiger respectively. Maharaja of Bundi estimated 75 tigers in 300 sq miles (750 km2) of his forest (Sankhala,
1978), which gives a density of 10 km2 per tiger in a dry deciduous forest of Rajasthan, higher than the densities in the researched areas.
iii. Error in the Logic of the Analysis:
Even if one concedes the erroneous presumptions made in the review, there is no logic in leading to a conclusion that the census methodology was at fault because 6 out of 18 tiger reserves (33%) exceeded the expected confines of the assumed standards for tiger
density and biomass.
(To be continued..)