Despite protection, cloud forest ecosystems and species see dramatic losses

Tropical cloud forests exist in 60 countries but account for less than a half of 1% of all land mass on Earth. Yet they are home to 15% of the world’s known species, researchers estimate.

Despite enormous conservation efforts, including designation of vast areas of forest as protected areas, and their typically isolated location, as much as 8% of some forests have been lost in the past 20 years to environmental encroachments such as logging and small-scale farming, according to a new Yale-led study.

These encroachments severely threaten the survival of the nearly 2,000 species of mammals, amphibians, birds, and tree ferns that live exclusively in these forests, according to a paper published April 29 in the journal Nature Ecology & Evolution.

“Tropical cloud forests are the terrestrial version of coral reefs. They harbor Earth’s greatest concentration of species diversity on land, over an already small and continually decreasing area,” said Yale’s Walter Jetz, professor of ecology and evolutionary biology and of the environment, director of the Yale Center for Biodiversity and Global Change (BGC), and senior author of the paper. 

“The study pinpoints where this has already led to the global extinction of species in recent years and demonstrates how protected areas, a key conservation measure, are failing in their stated goal of averting the dramatic erosion of this ecosystem and its species.”

In an international collaboration headed by the BGC Center, Jetz and colleagues used satellite and remote sensing data to assess change in tree cover from 2001 to 2018 for all the world’s cloud forests, which are marked by moist, tree-hugging fog, and are found in tropical regions of Indonesia, South America, and Africa. Globally, about 2.4% of cloud forests were lost during just that period, but in some regions those losses were as high as 8%, with the greatest declines occurring in the parts most easily accessible to people. 

As this critical habitat for species shrinks, extinction for some species will inevitably follow, said first author Dirk Karger of the Swiss Federal Research Institute for Forest, Snow and Landscape Research and BGC. Beyond the loss of biological heritage, the shrinking forests will also impair the functioning of an ecosystem that offers many vital services to people. Cloud forests act as water filtration systems, prevent erosion, and support important watersheds for human settlements.

“While protected areas have slowed the decline in cloud forests, in all but the most accessible areas, a large proportion of loss is still occurring despite such formal protection,” the authors conclude. “Increased conservation efforts and international support for the nations who are stewards of cloud forests are needed to support the impending regional or global demise of this unique ecosystem and its threatened biodiversity.”

Interactive maps and visualizations of the global cloud forest atlas and its 20-year change are available here.