Deprecated (16384): The ArrayAccess methods will be removed in 4.0.0.Use getParam(), getData() and getQuery() instead. - /home/brlfuser/public_html/src/Controller/ArtileDetailController.php, line: 150
 You can disable deprecation warnings by setting `Error.errorLevel` to `E_ALL & ~E_USER_DEPRECATED` in your config/app.php. [CORE/src/Core/functions.php, line 311]
Deprecated (16384): The ArrayAccess methods will be removed in 4.0.0.Use getParam(), getData() and getQuery() instead. - /home/brlfuser/public_html/src/Controller/ArtileDetailController.php, line: 151
 You can disable deprecation warnings by setting `Error.errorLevel` to `E_ALL & ~E_USER_DEPRECATED` in your config/app.php. [CORE/src/Core/functions.php, line 311]
Warning (512): Unable to emit headers. Headers sent in file=/home/brlfuser/public_html/vendor/cakephp/cakephp/src/Error/Debugger.php line=853 [CORE/src/Http/ResponseEmitter.php, line 48]
Warning (2): Cannot modify header information - headers already sent by (output started at /home/brlfuser/public_html/vendor/cakephp/cakephp/src/Error/Debugger.php:853) [CORE/src/Http/ResponseEmitter.php, line 148]
Warning (2): Cannot modify header information - headers already sent by (output started at /home/brlfuser/public_html/vendor/cakephp/cakephp/src/Error/Debugger.php:853) [CORE/src/Http/ResponseEmitter.php, line 181]
LATEST NEWS UPDATES | Tiger census

Tiger census

Share this article Share this article
published Published on Jan 30, 2015   modified Modified on Jan 30, 2015
-The Telegraph

New Delhi: Sections of wildlife biologists have questioned the methodology India has adopted for its tiger census, saying it does not yield results to accurately measure changes in numbers either within a particular region or across the country.

The Wildlife Conservation Society (WCS), a non-government partner that was involved in the tiger estimation exercise, said the "double-sampling" approach the Union environment and forests ministry adopted was "not the best currently available methodology" for this task.

The latest census, released by the ministry last week, has estimated that India has 2,226 tigers scattered across 47 reserve areas and adjacent patches of forests - a 30 per cent rise over four years.

"We believe the double-sampling methodology has some fundamental statistical flaws," Ullas Karanth, director, WCS, India, told The Telegraph. "This is not a robust approach - it should be considered obsolete."

The double-sampling strategy involves combining two sets of data to arrive at the estimate for tigers, either within a landscape or across the country. Scientists used 9,735 cameras to capture images of tigers in relatively small zones of tiger territories. They also asked forest guards to trudge across much wider areas, counting paw-marks and scat droppings to use them as proxy indicators of the presence of the big cats, and combined the data to arrive at the final estimates.

Karanth said the technique of combining the two sets of data - counts from camera traps and counts from indirect evidence of tigers - was based on a statistical approach proposed in 1938, but is viewed by many experts as not good enough to deliver reliable estimates for changes in numbers.

He said a more reliable estimate was likely to emerge from the environment ministry's ongoing exercise to estimate the number of tigers in 30 to 40 major "source populations", or areas where tigers are thriving and multiplying.

"These source populations hold over 90 per cent of all our tigers, and annual rigorous monitoring of these populations can yield more accurate tiger numbers, measure increases and decreases, and survival rates which are critical for the long-term fate of India's tiger populations," the WCS said in a media release.

India's population of tigers, presumed to be around 50,000 in the early 19th century, had dropped to 1,411 in 2006 before climbing to 1,706 in the 2010 census. In 1973, India had launched Project Tiger, a nationwide conservation effort to help protect the species and its habitat.

Karanth said the number of tigers has "definitely gone up", adding that voluntary relocation of villages from core tiger areas, enhanced patrolling, and expanding tiger reserves had helped increase the numbers of tigers in several states.

But the WCS has cautioned that tigers now occupy less than 200,000sqkm from the 380,000sqkm that was once considered tiger territory. Of this 200,000sqkm, only 20 per cent of the area supports any reasonable tiger densities and account for 90 per cent of India's tigers.

India's tigers are scattered across several distinct regions, or landscapes - the Shivalik-Gangetic plains; Central India and the Eastern Ghats; the Western Ghats, the Northeastern Hills and the Brahmaputra flood plains, and the Sunderbans.

"It is critical to expand the habitats holding the tiger source populations," the WCS said.

Karanth said other experts who have at various times questioned the double-sampling methodology include David Anderson, at the Colorado State University, James Nichols, at the US Geological Service, and Mohan Delampady at the Indian Statistical Institute, Bangalore.


The Telegraph, 30 January, 2015, http://www.telegraphindia.com/1150130/jsp/nation/story_10750.jsp#.VMrzBS7xxpB


Related Articles

 

Write Comments

Your email address will not be published. Required fields are marked *

*

Video Archives

Archives

share on Facebook
Twitter
RSS
Feedback
Read Later

Contact Form

Please enter security code
      Close