Dung study to ascertain elephant population at BNP (India)

A team of Forest officials and researchers has walked across the ranges of the Bannerghatta National Park (BNP) for three months, following elephants and examining their dung, as part of the dung decay rate study.

The first of its kind in the country, the entire exercise, conducted by a team of Forest department officials in association with researchers of IISc and volunteers of A Rocha, an NGO, was done to ascertain the population of pachyderms in different ranges of BNP and terrain details among others. 

Sunil Panwar, Deputy Conservator of Forests, BNP, told Deccan Herald, “If the exercise is successful, it would be implemented in different states, with sizeable elephant population, and would be made a part of an all-India elephant census.”

Samples collected

The team surveyed all ranges of BNP except Harohalli range, where elephant movement is the least. The surveyors walked across the terrain and collected at least five dung samples from each range, he added.

Sagarika Phalke, programme officer, A Rocha, told Deccan Herald, “The volunteers would walk a transect line and, if lucky, follow an elephant or a herd. Wait for them to defecate and walk on. Each dung sample is given an identification number. After 20 days, the site is visited again to ascertain the dung status – remains of the dung, how much and why.”
The data is then collated and calculated using formula – dung density multiplied by dung decay rate divided by defecation rate. 

The value of which will help ascertain the number of elephants per square kilometre in different ranges of the BNP. This is a part of the indirect elephant census (apart from direct sighting) and can be applied to all other animals including tigers, Sagarika explained.

She added that the standard rate of defecation of an elephant is 16 times a day and there will be around 20 dung piles per transect line.

Decay rate

Through this study, the decay rate is being ascertained for scientific calculation. This study is ideally done three months before monsoon. But presently, it is being extended for a couple of days because of the pre-monsoon showers. The detailed study report will be released by August-end.

As per the last elephant census done in 2007, BNP, spread over 270 sq km, housed 140 to 150 pachyderms.  The number has come down around 60, mostly females and calves, owing to migratory reasons.