Bangalore: As the Karnataka forest department
analyses data gathered during the six-day tiger census
conducted in January, outfits like Centre for Wildlife Studies
(CWS), Wildlife Conservation Society (WCS) and National Centre
for Biological Sciences (NCBS) have chipped in to identify the
population of the big cats.
"We are looking at identifying the individual tigers based
on their unique coat pattern and DNA fingerprinting from scats
(faeces)", CWS Director K Ullas Karanth said to a news agency.
This innovative DNA work was first developed last year,
initially in Bandipur, but will be expanded to other sites in
the coming months. NCBS is the lead institution in DNA
analysis work, he said.
Tigers are individually identified from camera traps
(automated cameras generally used to photograph nocturnal
wildlife) and counted. "The statistical models also tell us
what proportion of the tiger population was not photographed,
thus allowing us to make estimates," Karanth said.
Cameras are placed at select sites to estimate the density
of tigers in those areas.
Pioneered by Karanth in 1991 in Nagarhole, camera
trapping has since then been extended to Bandipur, Bhadra,
Anshi and Dandeli reserves in the last few years. Also camera
trap surveys have been completed in a dozen reserves outside
Karnataka between 1995 to 2004.
Detailing the advantages of camera traping vis-a-vis the
tiger census undertaken by the forest department, Karanth said
the tiger estimation exercise undertaken recently was not used
to estimate tiger number directly.
The effort there is to primarily measure where tigers are
present rather than numbers and densities. For getting those
numbers, camera trap surveys should be done. These are
calibrated against sign (including pug marks, scratch marks,
droppings) data, he said.
"Roughly these methods of DNA sampling and camera trapping
cost about Rs 20-30 lakh an year for monitoring a typical
Tiger Reserve area. Typically high density areas, where camera
trap usage is not a problem, we prefer camera trap surveys.
Other sites with low densities and problems using camera
traps, we prefer DNA sampling", Karanth said.
The six-day tiger census was conducted in Karnataka from
January 22-27, which comprised collection of data in all the
forests with a size of 10 sq km and above, said Chief Wildlife
Warden B K Singh.
"A team was constituted for each beat (administrative unit
allotted to a forest guard) for all the 2,819 beats in the
state for data collection. This data is then passed on to the
divisional headquarters and then after total compilation at
the state level, sent to Wildlife Intitute of India for
final collation", he said.
Simultaneously, WII will lay camera traps in represented
areas to check the data collected by the states.
"Besides forest department personnel, around 1,000
volunteers and technical experts participated in the exercise
which was carried out authentically through monitoring teams
and observers in high density areas", he said.
A 15 km trail was covered in each of the (2819) beats and
sign data collected for the presence of the carnivore. The
last three days were devoted to "ungulate (deer, cheetal,
sambhar which is food for the carnivore) encounters wherein a
one transect spanning 4 km each was created for each beat to
trace such hunts by the big cats through rake marks, pellets
(faeces) and vegetation survey", Singh said.
According to P C Sinha, Director WII in Dehradun, "the
census is being carried out across 17 states covering a forest
area of over three lakh sq km. In all probability the
estimation except in North-east and Sunderbans should be
completed by November end".