A team of researchers led by Matthew Luskin, a researcher at the Asian School of the Environment at Singapore's Nanyang Technological University, studied 15 Sumatran tiger forests and natural parks listed as UNESCO World Heritage Sites.
Their research revealed that the total population of the Sumatran tiger dropped to about 618 individuals in 2012 from 742 in 2000.
"The total potential island-wide population declined by 16.6 percent from 2000 to 2012 due to forest loss and degradation," the team revealed in a paper published Wednesday in the Nature Communications journal.
The findings also unveiled that lowland and hill forests, which have the biggest populations of tigers, have decreased by 21 percent due to palm oil plantations.
"We conclude that there are only two robust populations left with more than 30 breeding females, indicating Sumatran tigers still face a high risk of extinction unless deforestation can be controlled," the report adds.
There are currently less than 600 tigers in the wild, rendering them "critically endangered" under the International Union for Conservation of Nature.
"I think our report provides the most comprehensive and robust evidence to date that habitat loss [is] pushing the Sumatran tigers dangerously toward extinction in the world," Luskin wrote in an email to Mongabay News.
Over the last 20 years, the primary threat to Sumatran tiger populations has shifted from poaching to habitat loss, Luskin also noted.
The Indonesian government is heavily invested in conserving the Sumatran tiger, especially since the two other tiger subspecies native to Indonesia, the Javan tiger and the Bali tiger, both went extinct in 2003 as a result of poaching and habitat loss.
"The threats to tigers' survival in Sumatra are critical. We would like a complete stop to all future deforestation and zero tiger poaching in all remaining tiger landscapes," Luskin said.
"We hope [our report] serves as a wake-up call."
