Wild elephant population stable in Kerala: census

A herd of wild elephants at the Vallakadavu forest range, Periyar Tiger Reserve, Thekkady. File photo: H. Vibhu   | Photo Credit: H_Vibhu

The wild elephant population in the Kerala forests has remained stable and healthy between 2007 and 2010, according the 2010 wild elephant census results received by the Forest Department this week.

The 2010 census, according to what is called ‘block count method’ of enumeration, puts the number of wild elephants in the State’s wildlife sanctuaries and protected areas at 3,520. The same method of enumeration in the previous census conducted in 2007 had put the number at 3002.

According to the ‘dung count method’ followed during the 2010 census, the number of wild elephants in the State’s forests comes to 6,026. This method of estimation had put the wild elephant population at 6,068 in 2007. Statistical analysis of the survey details was done by scientists at the Kerala Forest Research Institute.

The State’s Chief Wildlife Warden Raja Raja Varma told The Hindu the purpose of the census was not to do an exact enumeration of the wild elephants (which was perhaps impossible), but to feel out general trends. The periodical census is conducted simultaneously in all the States having wildlife tracts, following certain guidelines from the Directorate of Project Elephant under the Ministry of Environment and Forests.

Under the ‘block count method’ of enumeration, trained volunteers, forest officials and tribal trackers perambulated from sunrise to sunset on May 15, 2010, through 50 per cent of the forest tracts in the State, demarcated as blocks on GIS maps. They counted wild elephants by direct sighting in each of these selected blocks, noting also the habitat type and the age-sex composition of the elephants. The numbers from the counted blocks were extrapolated for the entire elephant habitat.

The technique of ‘line transect sampling’ was followed for the survey in the same sampled blocks on May 16, 2010 for counting elephant dung piles in the forests. There is a scientifically established method of estimating the elephant population in an area by counting the dung piles and applying certain formulas for converting the dung quantity into the elephant population. Dung decay rate is a factor in this estimation.

The direct sighting ‘block count method’ always tends to give an under estimation of the actual number since the heavily wooded tracts make sighting incomplete. And, in the dung count method, the decay rate determined through laboratory tests varies from season to season and its accuracy, as tested under the conditions prevailing at the time of the survey, is a key factor in the estimation.

There were three cow elephants for every bull elephant sighted during the survey. In the sub-adult category, the ratio of male to female elephant in the wildlife population was 1:2. And for every three adult cows, there was one calf in the elephant population. Twenty-four per cent of the adult and sub-adult elephant population constituted tuskers. “These are healthy numbers,” Mr. Varma said.

Wayanad Elephant Reserve (WER) had the highest elephant density among the four elephant reserves (which, together, encompass all the wildlife sanctuaries and protected forests) in the State. The elephant density in WER was found to be 0.5798 per kilometre under the block count method. It is followed by Anamudi Elephant Reserve (0.5304 per kilometre), Periyar Elephant Reserve (0.4226) and Nilambur Elephant Reserve (0.1799).

“This census helps us introduce corrective measures in our conservation efforts when unhealthy developments are indicated. Initial impressions are good this time. We will subject the data to further scrutiny, examining the details at the level of individual sanctuaries and protected areas and also examining them at the wide area level when the census results from the forests in neighbouring States lying contiguous to the forests of our State become available,” the Chief Wildlife Warden said.

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Printable version | Apr 14, 2021 12:17:10 AM |

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