Along the trails through Medog, Xu would often turn a stone or a piece of rotten wood upside down in search of ants. Once he found his quarry, the professor would sit down on a stone, shovel the soil containing the ants into a plastic dish with a garden spade and start picking out his samples, one tiny one after another, with a pair of tweezers.

It was a bumper harvest for Xu every day. During the journey, the professor collected more than 1,200 samples of nearly 100 species of ants.

"Many of them might be new species, since no one has been to Medog to study ants before," Xu says.

"Ants are an important indicator of a region's biodiversity. The rich variety of ants I collected here truly reveals the area's extraordinary biodiversity."

The road ahead

The situation was less rosy for the region's large mammals, another important indicator of the local environment.

Wang Hao, the survey's coordinator and a researcher on large mammals, was frustrated at not being able to see any large mammal in Medog's wild. Except for leopard cat droppings spotted at several sites, the 35-year-old found virtually no sign of any other big animal in the region's forests.