Wild Tigers Becoming Too Inbred
Krishnendu MukherjeeKrishnendu Mukherjee, TNN Oct 3, 2011, 03.59AM IST
KOLKATA: On her last legs, Machli – often called Ranthambore’s matriarch for presiding over a majestic legacy of over a decade – can still make a tiger-lover crave for her glimpse. But her offsprings in the 400-500 sq km tiger abode in Rajasthan’s Sawai Madhopur district face a genetic threat that could hit the population hard in the long run.
While Ranthambore Tiger Reserve (RTR) was in news for a sudden population crash in 1992 and 2003, it assumes more significance in the light of a recent study by the Wildlife Institute of India (WII) that says tiger population in the park has shown a loss of genetic diversity over the years. “RTR tiger population is showing loss of many alleles, which may be due to an isolated population without any genetic exchange,” said WII’s Dr S P Goyal, the investigator of the report – ‘Tiger Genome: Implications In Wildlife Forensics’. Alleles are a group of genes that decide an animal’s hair colour and immunity, among other characteristics.
The park’s tiger population had crashed to 12 in 1992 and 13 in 2003. It bounced back to 31 in 2010 but Dharmendra Khandal, a conservation biologist, feels lower genetic diversity would prove to be a new threat.
“Urbanisation and fragmentation in tiger corridors are the reasons. Ranthambore tigers used to take the Chambal river route to reach Madhya Pradesh’s Kuno. But flattening of the river banks stopped tiger dispersal between Ranthambore and MP, resulting in no gene flow between the two tiger populations,” he said.
“Since Sariska has lost all its tigers, now the nearest tiger reserve from Ranthambore is over 800 km away, be it Bandhavgarh, Corbett or Satpura,” Khandal said. According to tiger expert Valmik Thapar, a growing human population is leading to encroachment of large landscapes making the survival of many species difficult.