The Bukit Barisan Selatan National Park, a world heritage site, is home to about 40 Sumatran tigers. There are fewer than 400 left in the wild.
It is also home to 60 of the 85 critically-endangered Sumatran rhinoceros and 500 Sumatran elephants, a quarter of the remaining population.
|The WWF says traders mix legal and illegal |
beans before export [GALLO/GETTY]
"About 17 per cent of the national park area is being cultivated for coffee," Nazir Foead, director of policy and corporate engagement for WWF-Indonesia, said on Wednesday.
"If current trends continue, in 10 years' time the area could double, causing significant impact to the species' habitats."
The tigers and rhinoceroses could be locally extinct "in less than a decade" as they are particularly vulnerable to changes in their habitat, said the WWF.
Indonesia is the world's fourth-largest coffee exporter and second-largest producer of robusta beans often used in instant and packaged coffee.
The tainted beans are exported to at least 52 countries, the WWF said.
It added that the trail of tainted coffee beans led from the park to multinational companies and on to supermarkets in the US, Europe and Asia.
"We think even the world's most committed coffee drinkers will find this an unacceptable price to pay for their daily caffeine buzz"
The group conceded the possibility that coffee giants may be unaware of the origin of the beans.
"I think they don't know where the coffee comes from. The village and sub-district traders are mixing the [illegal and legal] coffee," said Nazir, who authored the report.
He said all coffee exported from the port of Lampung adjacent to the park were tainted.
The Indonesian forestry ministry could not be reached for comment.
Swiss food giant Nestle has pledged to clean up part of its supply chain and show farmers how to produce high-quality coffee while other companies were in preliminary discussions with the WWF on the issue, the report said.
"We think even the world's most committed coffee drinkers will find this an unacceptable price to pay for their daily caffeine buzz," Nazir said.