As the Karnataka forest department analyses data gathered during the six-day tiger census conducted in the state in January, various wildlife organisations have chipped in to identify the population of the big cats based on DNA finger printing.
“We are looking at identifying the individual tigers based on their unique coat pattern and DNA fingerprinting from scats,” Centre for Wildlife Studies (CWS) Director K Ullas Karanth told PTI.
This innovative process (DNA analysis), first developed last year in Bandipur National Park, will be expanded to other sites in the coming months. National Centre for Biological Sciences (NCBS) is the leading institution in DNA analysis work, he said.
Currently, tigers are individually identified from camera traps (automated cameras 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 Nagarhole National Park (recently been renamed Rajiv Gandhi National Park) in 1991, 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 trapping 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.