Indian tigers face inbreeding threat due to forest fragmentation, shows genetic study

HYDERABAD: The recently released tiger census data brought much cheer due to the reported rise in population of tigers in the country. However, a serious threat to the survival of Indian tigers looms large because of inbreeding, caused due to lack of contiguous stretch of forests and destruction of tiger corridors.

A consortium of researchers including from the Stanford University, National Centre for Biological Sciences, Bengaluru and Hyderabad-based Laboratory for Conservation of Endangered Species (LaCONES) conducted a first-of-its-kind genetic study on the Bengal, Malayan, Amur and Sumatran tigers.

The researchers observed that although Indian tigers are genetically much diverse than their Russian, Malaysian or Indonesian counterparts, individual genetic samples indicated recent inbreeding among Indian tiger population.

Inbreeding can be detected through a parameter called runs of homozygosity(ROH). The researchers found that some Indian tiger individuals had higher ROH values. Higher ROH values were especially found among south Indian and north-western Indian tigers. They also found that although genetic diversity was low among Malayan, Amur and Sumatran tigers, they had lower ROH values than Indian tigers, indicating that these species did not experience much inbreeding.

While tiger reserves continue to be protected in the country, the forests outside tiger reserves, especially forests connecting two tiger reserves known as tiger corridors are coming under destruction, due to various projects and encroachments.

As a result, tiger population in tiger reserves remain isolated in their habitats without much scope to move out and mate with tigers. Inbreeding among tigers is dangerous, as it is among humans. It can seriously impact the health of tigers.