Things appeared to be looking up for the world's favorite threatened species. China has pumped money into protecting its prized giant pandas, and last year the International Union for Conservation of Nature (IUCN) downgraded its status from "endangered" to "vulnerable."

But a new study warns against complacency, revealing that pandas are under growing pressure from habitat loss, tourism and climate change.

A team of scientists used geospatial technologies and remote sensing data to map human development encroaching on the last bamboo forests where these iconic beasts survive.

"What my colleagues and I wanted to know was how the panda's habitat has changed over the last four decades," said Stuart L. Pimm, one of the study's authors, "because the extent and connectivity of a species' habitat is also a major factor in determining its risk of extinction."

Fenced in by roads

Comparing satellite imagery dating back to 1976, they found that the giant panda's habitat had shrunk and become increasingly fragmented over the last four decades.

The research team included Jianguo Liu of Michigan State University and Zhuyan Ouyang of the Chinese Academy of Sciences, who have studied the panda's geographical range since 2001.

"The most obvious changes in this region since Professor Liu and his colleague Professor Zhiyun Ouyang first visited it together in 2001 have been the increase and improvement in roads and other infrastructure," Pimm, a professor of conservation ecology at Duke University in the United States, said in a press release.

"These have been the major factors in fragmenting the habitat. There was nearly three times the density of roads in 2013 than in 1976."

They found that the remaining panda population is split into 30 isolated groups, 18 of which consist of fewer that 10 animals - meaning there is a high risk of local extinction.

A complex picture

The study also questions the data that changed the IUCN status, which found an overall increase in the giant panda's overall population. The study found the methods and territories studied were not consistent between assessments.

The scientists say the picture is a complex one, with some encouraging signs. Overall, the pandas' habitat fell five percent between 1976 and 2001, but individual patches supporting the endangered animals shrunk by an average of 24 percent.

There has been a small increase in overall territory since 2001, the team said, with a ban on commercial logging and new nature reserves since 1996 having a positive impact. But these small gains were well short of offsetting the habitat loss over the previous two decades.

Panda were first listed as an endangered species in 1988.

Call for habitat corridors

Growing tourism to protected areas, changes to forest management regulations that result in logging, and climate change, which could alter the distribution of the bamboo they feed on, also threaten the panda's survival, the study says.

The scientists say the most urgent action needed is to establish corridors of habitat to connect isolated, vulnerable populations of pandas.

"Conservation is a dynamic process with humans and nature in a constant push and pull to survive and thrive, so new solutions always are in demand," Liu said.