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..)
Monitoring Tigers in the Twenty-First Century India-Part IX
Here is the ninth 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: firstname.lastname@example.org
(Continued from last month)
(3) Evaluation of the Experiment
A great amount of skepticism about the findings from the experiment was voiced but not documented. The source of skepticism will be apparent from a revisit to the experiment conducted in the zoo.
i. Flaws in the concept and design of the experiment:
Prima-facie, the errors and incongruities in the premises crept into the design and conduct of the experiment. The ambiguity in the basic premise prevents the association of the experiment with either of the field methodologies.
a. The design of the experiment did not follow either the Co-operation Tiger Census method or the ‘Pugmark Census’ Technique in its approach. Choudhury had emphasized that “the tiger pugmark is one of the reliable parameters when the impression is true in
size and features, which happens on thin powdery surface soil … a pugmark of a tiger taken from sand or fluffy soil cannot give reliable comparison with that of another tiger taken from thin powdery surface soil” (Choudhury, 1970b). The experiment by design
presented pugmarks on two substrates for testing the participants and making a conclusion about the methodology.
b. The claimed length of experience of the participants should have been established beyond doubt. In practice, Project Tiger organized tiger census once in four years at National level and once in two years at State level. For the participants to acquire
experience of 4 to 6 census years they would have had to spend a minimum of 7 to 11 years on postings in tiger conservation units. Similarly, for the experience of 12 census years the said participant would need to spend 23-24 years on such posting(s). Given
the tenures normally allowed by the government to the wildlife managers there is a chance that the reported length of experience with tiger census was misrepresented. Some of the participants may have had experience with census work on only one or two occasions!
ii. Flaws in the conduct of the experiment
a. The experiment stopped at asking the participants to identify tigers from a single parameter – the pugmark. The experiment did not provide the participants with the range of information used in either the ‘Co-operation Tiger Census’ technique, or the
‘Pugmark Tiger Census’ technique for elimination of human bias and duplication in counting tigers. The missing parameters were: location from where pugmarks were collected, the average stride and straddle of the tiger, and the placement of the tigers’ pugmarks
with respect to the direction of their movement. Inadequate data was presented as a part of the design of the experiment.
b. No replications of the experiment were carried out – the interpretation of results was made from a single sample survey.
(a) In the experiment a serious anomaly was visible: 70% of the participants had made statistically significant correct choices in distinguishing the sex and the pugmarks of tigers, yet they had completely failed in identification of individual tigers and
tiger counts. There was an imperative need to further investigate into the source of anomaly. Scientific research protocol also demanded replication of experiment with different sets of participants.
(b) Replications with different set of participants were also called for since tiger census was being practiced in other States, too. It would have eliminated any chance of the participants having been exposed to a non-standard method. But there was no such
replication of the experiment.
(To be continued)