Photo: Agent Green/AP
An area of montane forest larger than the state of Texas has been lost since 2001, with amounts disappearing at an “alarming” rate each year, a study warns.
Scientists found that over the past two decades, 78 million hectares (193 million acres) of montane forest have been lost worldwide, which is more than 7% of all that exists. The main causes of damage were logging, agricultural expansion and forest fires.
Mountains are home to more than 85% of the world’s birds, mammals and amphibians. These habitats were once more protected than their flatland equivalents because their rugged terrain made them less accessible, the paper notes. Today, they are increasingly threatened as humans exploit hard-to-reach areas of the planet and lowland forests become more protected.
“Our global analysis of mountain forest loss shows an alarming acceleration over the past two decades,” the researchers, led by scientists from the University of Leeds and the Southern University of Science and Technology in China, wrote in the article published in the journal One Earth .
They found that logging was responsible for 42% of montane forest loss, wildfires for 29%, slash and burn for 15%, and semi-permanent or permanent agriculture for 10%.
Researchers tracked changes in the forests between 2001 and 2018, documenting both increases and decreases in tree cover and elaborating potential impacts on biodiversity. They found that Asia, South America, Africa, Europe and Australia were all badly affected. Much of the casualties in North Asia were due to wildfires, particularly in much of Russia. Drought and bushfires caused significant damage in Australia.
The annual loss rate rose sharply after 2010, increasing by 50% from 2010 to 2018 compared to 2001 to 2009. The expansion of agriculture and logging in the highland areas of Southeast Asia proved to be a key factor. During the study period, more than half of the world’s forest loss occurred in Asia.
The climate crisis is putting pressure on specialized – and often sensitive – mountain wildlife as warmer temperatures force species to migrate to higher elevations. Eventually, they will likely run out of suitable habitats, a process known as the “escalator to extinction.”
Previous studies have shown that alpine plants are not keeping pace with climate change as invasive species colonize the mountain tops at a faster rate. Botanists working in the Scottish Highlands also noted that Britain’s rarest mountain plants retreated higher.
Related: Largest carbon credit certifier replacing its rainforest offset program
In this latest paper, the researchers warn, “Mountain forests in many regions are undergoing dramatic changes due to their sensitivity to climate change and anthropogenic pressures, which are becoming major threats to mountain species.”
More than 40% of the total loss occurred in tropical montane forests, which are considered biodiversity hotspots, further increasing the pressure on threatened species. Zhenzhong Zeng of Southern University of Science and Technology, one of the authors of the article, said: “What requires our attention is that the loss of montane forests has encroached into areas known to have high conservation value for terrestrial biodiversity, particularly in the tropics. Various types of agricultural expansion and forestry activities are important drivers there.”
The paper found that creating protected areas within biodiversity hotspots reduced the rate of loss. “Increasing the protected area in the mountains should be of central importance for the preservation of mountain forests and biodiversity in the future,” it said.
dr Marco Mina, a researcher at the Institute for Alpine Environment, Eurac Research, in Italy, who was not involved in the study, said: “My general opinion is that using large-scale data, such as remote sensing satellite products, is a great tool to predict forest changes near in to monitor real-time. However, we should be careful about drawing global conclusions solely based on remote sensing products.
“A forest that is well managed through a careful planning process can still provide a high level of habitat for both plant and animal species.”
For more coverage of the Age of Extinctions, click here and follow biodiversity reporters Phoebe Weston And Patrick Gruenfeld on Twitter for all the latest news and features