Forests still large enough to double the world's tiger population, study finds

Forests that harbour tigers are being lost but are still large enough to take double the world’s tiger population in the next six years, according to a study using new satellite mapping technology.

But the internationally agreed goal can only be achieved if no further habitat across Asia is lost and if the “corridors” that connect tiger populations are protected, researchers warn in the paper, published on Friday in the journal Science Advances.

The tiger is the most endangered big cat, with as few as 3,200 left in the wild in the forests, swamps and jungles of 13 Asian countries. Logging, agricultural expansion and infrastructure development have all cut their habitat and they are also under severe pressure from hunting and poaching for their body parts, which are used in traditional Asian pseudo-medicine.

By 2010 the rate of loss was so great that a high-level summit was convened in Russia, where tiger nations agreed on a goal called Tx2 to double the world’s wild tiger population by 2022.

Since the meeting, Nepal and India have reported an increase in tiger populations, Amur tiger numbers are rising in Russia and there are indications that tigers are settling and breeding in north-eastern China. Later in April, India will host a ministerial conference where countries will report on their progress.

The new analysis, led by Anup Joshi at the University of Minnesota in St Paul, in the US, shows that despite an overall decline in habitat between 2001 and 2014, enough wild habitat remains to meet the goal.

The researchers used Google Earth Engine’s cloud computing platform to process huge amounts of high-resolution, real-time satellite imagery and 14 years of forest loss data from Global Forest Watch. This allowed them to calculate changes in tiger habitat to the level of detail of 30m in a single wildlife corridor and at a wider scale across 76 landscapes that have been prioritised for the conservation of wild tigers.

Previously, Joshi said, monitoring tiger habitat could only be done once a decade because of limited access and expertise in satellite monitoring technology. Using the new technology, conservationists can pinpoint exactly where habitat loss is occurring and potentially curb future losses.

“The tiger countries have set the goal to double numbers – we are bringing them the tools to plan and meet their target,” said Joshi. “We have developed a tool that anyone in those countries can use without having remote sensing expertise. Now we can monitor forests annually and provide this info directly over the web, making people more accountable.”

Altogether, around 80,000 km2 of forest was lost across all 76 of the tiger landscapes studied, with more than 58,000 km2 occurring in 29 priority areas.

They found that forest loss in the areas studied – 7.7% between 2001-2014 – was far less than anticipated, something they found “remarkable and unexpected” given that the 13 tiger range states represent some of the fastest-growing economies in the world, with $750bn expected to be invested in infrastructure projects annually over the next decade.

“Most encouraging was that loss was less than expected in the 51 tiger reserves,” the paper said. “This suggests that if future habitat loss is prevented, the tiger recovery in some range states will accelerate. In these promising locales of enhanced protection, a doubling of the tiger population could be attainable by 2022.”

Among the 29 landscapes deemed most critical for increasing tiger numbers, 10 accounted for more than 98% of the loss, with the greatest loss in Malaysia and Sumatra and extensive loss in areas of oil palm expansion.

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The impact in those 1o areas was deemed “devastating”. For example, the Cambodian northern plains landscape, which contains five large reserves of tropical dry forest, has lost habitat that would support more than 170 tigers.

“There are three important things for the conservation of tigers,” Joshi said. “Habitat, anti-poaching efforts and maintaining tiger prey species. We want this study to encourage people to think that doubling numbers is possible but we don’t want to paint too rosy a picture.”

Rebecca May, from WWF-UK’s tiger programme, who was not involved in the research, said: “This year is a critical halfway point in the TX2 goal. We know that populations have been increasing in some countries,proving tiger population recovery is possible when governments, environmental organisations and local communities work together. However, we still have a long way to go, as tigers remain seriously threatened by poaching and habitat loss.”