The gaur population in Kui Buri National Park in Prachaup Khiri Khan province is still at risk of extinction due to inbreeding and a possible re-occurrence of a disease outbreak that has killed 29 wild gaurs since last year, experts say.
Kanita Ouitavon, chief of the Wildlife Forensic Science Unit of the Department of National Parks, Wildlife and Plant Conservation, said the genetic haplotype diversity found in gaurs in Kui Buri National Park is low. That's seen as a dangerous sign of inbreeding among the gaur population.
Haplotypes are a set of DNA sequences passed down from parents to offspring. Genetic changes in offspring can be tracked by comparing their haplotypes to those of their parents.
According to the research conducted by Ms Kanita, only three genetic haplotypes were detected in 26 of 29 gaur carcasses found in Kui Buri since December last year, compared with two haplotypes collected from only two gaurs in Huay Kha Khaeng Wildlife Sanctuary in Uthai Thani province.
"We found the A haplotype in 18 gaur carcasses, which shows the inbreeding trend is rising in the park," she said, adding that inbreeding has led to low immune resistance against disease.
She said that one cause of inbreeding is the over-hunting of gaurs which began around 50 years ago, after people formed communities close to their habitats.
Supagit Vinitpornsawan, a wildlife expert with the Wildlife Conservation Office, said the study found the wild gaur population has fallen by half in the past two decades, except in heavily protected wildlife areas.
He said the age of the gaur population is also a concern since the number of baby gaurs is quite low compared to the numbers of more mature gaurs, which means a rapid growth rate is unlikely. That adds to the threats facing the gaurs.
However, Mr Supagit said disease outbreaks could already be under control because no more gaur deaths have been reported since the last carcass was found in May.
Tuangporn Patchimsiri, of the National Institute of Animal Health, said tests show that foot and mouth disease (FMD) and "black disease" (necrotic hepatitis) are thought to be the main causes of the high number of deaths.
The tests found one living female gaur has anti-bodies for FMD type A, which was also found in two gaurs that died between April and May.
"The good news is that we have assumed those gaurs have anti-bodies of the diseases, but the bad news is the problem might return if the diseases have changed to a different type. The diseases remain in the park right now," she told an annual meeting on biodiversity studies hosted by the Department of National Parks, Wildlife and Plant Conservation.
Prawatsart Chantrarathep, chief of Kui Buri National Park, said measures have been prepared to prevent outbreaks, including sanitary systems for visitors. He added that efforts are underway to find the source of the disease outbreaks.
Contrary to earlier reports the park had reopened to visitors, he said staff want to focus on finding the disease sources first. Locals had hoped the park would reopen as soon as possible to boost incomes from tourism.