Biodiversity at risk as mountain forests shrink at worrying rate: study

Globally, we have lost 78.1 million hectares of mountain forest since 2000 - an area larger than Texas.

This is a 7.1 percent loss of our planet’s mountain forests.

More than 85 percent of the world’s bird, mammal, and amphibian species live in mountains, particularly in forest habitats, meaning this loss is extremely concerning for those who call it home.

Logging has been the biggest driver of mountain forest loss, contributing to 42 percent of global depletion.

Wildfires made up 29 percent, while permanent or semi-permanent agriculture contributed to 10 percent.

Shifting and “slash-and-burn” cultivation, where forests are burned and cleared for planting, also played a part, contributing to 15 percent.

The importance of these different factors varied from region to region.

Tropical mountain forests experienced the most loss, making up 42 percent of global depletion.

It also had the fastest acceleration rate compared to mountain forests in temperate and boreal regions, however, it did have a quicker regrowth rate.

Since the 21st century, these once protected forests have become increasingly exploited.

The authors suggest this is most likely due to rapid agricultural expansion into highland areas in mainland Southeast Asia.

They believe it is also down to increased logging of mountain forests as a result of either forest depletion or an increase in protection of lowland forests.

The team tracked these changes yearly from 2001 to 2018.

They took the data of loss and growth in tree cover and estimated the rate at which these changes occurred.

They also compared different elevations and types of mountain forests, including boreal, temperate and tropical, and explored the impacts of this forest loss on biodiversity.

The rate of mountain forest loss is now accelerating annually.

The annual rate of depletion increased by 50 percent from 2001-2009 to 2010-2018.

During this time, we lost around 5.2 million hectares of these forests each year.

Study co-author Zhenzhong Zeng, an associate Professor from Southern University of Science and Technology in China, said: “Knowledge of the dynamics of forest loss along elevation gradients worldwide is crucial for understanding how and where the amount of forested area available for forest species will change as they shift in response to warming.”

Significant loss occurred in Asia, South America, Africa, Europe, and Australia.

North America and Oceania did not experience too bad a loss.

However, it isn’t all doom and gloom. The researchers found some signs of tree cover regrowth in 23 percent of the areas that lost forest.

Protected areas experienced less forest loss than unprotected areas, but the researchers caution that this might not be enough to preserve threatened species.

Dr, Zeng said: “Regarding sensitive species in biodiversity hotspots, the critical issue extends beyond simply preventing forest loss.

“We must also maintain the integrity of forests in large enough zones to allow natural movements and sufficient space for ranging species.”

Dr Zeng added: “Any new measures to protect mountain forests should be adapted to local conditions and contexts and need to reconcile the need for enhanced forest protection with ensuring food production and human wellbeing.”

The study was published in the journal One Earth.