Maintaining that its recent elephant population estimation exercise was “more precise” than the previous surveys, the Forest department has stood by its migration theory to explain the fall in elephant population, with their habitats in Kerala being contiguous with the forests of Karnataka and Tamil Nadu sharing an inter-State boundary length of 957 km.
While both block count and dung count methods were adopted for the exercise, it estimated populations of 1,920 and 2,386 elephants respectively. These were significantly lower than the respective counts estimated using the two methods in 2017 – 3,322 and 5,706.
Also read: Latest census reports a dip in tiger, wild elephant populations in Kerala
While the sharp fall in population raised eyebrows, forest officials attributed the high numbers during the last edition to unscientific sampling.
In its Elephant Population Estimation in Kerala 2023 report, accessed by The Hindu, the department emphasises the importance of ensuring care while selecting sample blocks for the direct count method in order to ensure that it is a true representation of the area.
While the manageable sizes of the representative sample blocks are ideally between 4 sq km to 6 sq km, some of the sampling blocks used during the earlier estimations were either oversized or undersized, thereby creating the possibility of inaccurate estimation. Samples blocks as large as 8-10 sq km and even more had been selected during the earlier estimations, the report stated.
The current estimates, it added, are more precise due to the fine-tuned methods adopted during the survey such as rationalisation of blocks with manageable sizes, careful selection of non-adjoining blocks that avoided double counts and the use of digital maps to clearly understand sample block boundaries even during field work.
Bolstering its inferences, the department points out that a severe drought in Tamil Nadu had resulted in a mass movement of elephants to the wetter forests of adjoining States from 2016. This was reflected in the higher numbers recorded during the population estimation in 2017.
Mortalities
The study also highlighted the deaths of 678 elephants between 2015 to 2022, with a high mortality rate being observed among calves and juveniles. While 275 of these were aged less than 10 years, as many as 155 were aged between 10 years and 20 years.
The high rate of deaths among young pachyderms aged less than 10 years is suspected to be due to the prevalence of elephant endotheliotropic herpesvirus (EEHV) or elephantid betaherpesvirus 1 (ElHV-1) among wild elephants.
The report also cited studies conducted in Asia that revealed that around 80% mortality caused by EEHV or ElHV-1 were found in calves aged below eight years. The department has called for exploring proven treatments to be adopted to minimise such deaths.
While the forests in Kerala are divided into four elephant reserves, viz., Wayanad, Nilambur, Anamudi and Periyar, the highest abundance of elephants was seen in the Periyar elephant reserve.
