Satellite Imagery Reveals that Tiger Populations Could Double by 2022

At the turn of the 20th century, roughly 100,000 wild tigers roamed the forests of Eurasia. Today, that number has dwindled to a global population of under 3,500 individuals, driven to the brink of extinction by anthropogenic pressures like poaching and the loss of 90 percent of their historic range to human encroachment.

But the good news is that this iconic predator is finally beginning to rebound in some areas, in the wake of concerted efforts to restore its habitat. The extent of this slow bounceback is analyzed in detail in a study published on Friday in Science Advances, which collates satellite observations of forest loss from 2000 to 2014 in 76 regions earmarked for tiger conservation across 13 countries including China, India, Indonesia, and Russia.

The team, led by University of Minnesota conservation scientist Anup R. Joshi, demonstrate that this space-down Big Data approach is proving to be instrumental in tracking the recovery of tigers with precision detail and in near-real time. Satellites allow scientists to see exactly which stretches of the animal's limited range are imperiled the most, and they can use that global view to make estimates about the health of tiger populations and to direct resources to threatened areas.

"Our analysis wouldn't have been possible without free access to satellite data and Google Earth Engine [Google cloud] for computation," Joshi told me via email.

"[M]ore governments and organizations are providing free data to the public," he continued. "With advances in technology, more data on Earth observation is coming in every day than we can analyze. Machine learning algorithms are becoming more reliable, which will change the way we monitor forest and other natural resources in coming years, to quickly analyze large data sets and identify trouble spots."

In particular, this study focused on the progress toward the "Tx2" goal, set by the governments of tiger-inhabited countries in 2010, which aims to double the worldwide tiger population to 6,000-plus individuals by 2022.

In a pleasant twist, satellite imagery sourced from Google Earth Engine and Global Forest Watch revealed that forest loss was not as bad as anticipated, with most of the trouble spots confined to only ten of the 76 prioritized landscapes, according to the new study. This means that reaching the Tx2 goal is still on the table, so long as conservationists continue to ensure tiger habitats are restored and protected.

That said, the data confirmed that the conversion of tiger habitat into farming and urban communities continues to plague the cats—particularly with regards to oil palm plantations.

"Expanding oil palm plantations in the tiger range countries has been one of the main causes of forest conversion and habitat fragmentation and loss," Joshi said. "In Indonesia alone, more than 4,000 square kilometers or 1,544 square miles of forests have been allocated for oil palm concessions."

"Forest clearing has a direct effect on tiger habitat and its prey species. Tigers need large areas to meet their food, shelter, and mate needs. Others threats are growing infrastructures, such as roads and cities to support the increasing human population."

Indeed, tiger territory frequently overlaps with dense rural human populations in nations with some of the fastest-growing economies on Earth, such as China and India. That is bound to be disruptive to their habitat and breeding. But as our space-down view of the world becomes sharper, it will be easier to identify which areas require the most urgent attention.

As an example, Joshi's team zoomed in on satellite footage of the Khata and Basanta corridors in Nepal, which are forested links between larger wildlife reserves. The results revealed a stark contrast: the Khata corridor is thriving due to forestry stewardship efforts and anti-poaching campaigns, while the Basanta corridor has been crippled by increasing human encroachment. It is this kind of precision analysis of specific regions that will help tiger advocates to root out where conservation efforts are failing, and further intervention is needed.

The best part is that this technology is not accessible to scientists alone; anyone can go to Google Earth Engine and Global Forest Watch to keep an eye on critical tiger habitats.

"Local communities will be able to see how their government officials are managing forest resources, protected areas," Joshi said. "Likewise, donors and advocacy groups would be able to monitor projects thus more transparency and accountability. When people have interactive tools which are simple to use, more people will participate in discussing issues and coming up with solutions."