One EarthCellPressArticleAccelerating global mountain forestloss threatens biodiversity hotspotsXinyue He,1.2 Alan D.Ziegler,3 Paul R.Elsen,4 Yu Feng,1.5 Jessica C.A.Baker,2 Shijing Liang,1 Joseph Holden,6Dominick V.Spracklen,2 and Zhenzhong Zeng1.7.*iSchool of Environmental Science and Engineering,Southem University of Science and Technology,Shenzhen,China2School of Earth and Environment,University of Leeds,Leeds,UKFaculty of Fisheries and Aquatic Resources,Mae Jo University,Chiang Mai,ThailandWildlife Conservation Society,Global Conservation Program,Bronx,NY,USASchool of Geography,University of Leeds,Leeds,UKLead contact"Correspondence:zengzz@sustech.edu.cnhttps://doi.org/10.1016/j.oneear.2023.02.005SCIENCE FOR SOCIETY Mountain forests are currently undergoing dramatic changes in many regions dueto their sensitivity to climate change and anthropogenic pressures,which will become a major threat tomountain species.Infommation is thus needed regarding which mountains are experiencing the most forestloss,to what extent biodiversity is affected,and whether current protected areas work.Our global analysisof mountain forest loss shows accelerating mountain forest loss in the early 21 st century.Primary drivers ofthe losses are commercial forestry,agriculture,and wildfire,but patterns differ worldwide.Unfortunately,heavy forest losses have occurred in many mountain areas that are biodiversity hotspots.However,pro-tected areas in most countries have been effective to some degree in preventing forest loss inside thesehotspots.The development and management of additional appropriately designed protected areas shouldfacilitate improved biodiversity conservation and forest management.SUMMARYThe frontier of forest loss has encroached into mountains in some regions.However,the global distribution offorest loss in mountain areas,which are home to >85%of the world's birds,mammals,and amphibians,isuncertain.Here we combine multiple datasets,including global forest change and selected species distribu-tions,to examine spatiotemporal patterns,drivers,and impacts of mountain forest loss.We find 78 Mha ofmontane forest was lost during 2001-2018 and annual loss accelerated significantly,with recent losses being2.7-fold greater than those at the beginning of the century.Key drivers of mountain forest loss include com-mercial forestry,agriculture,and wildfire.Areas with the greatest forest loss overlap with important tropicalbiodiversity hotspots.Our results indicate protected areas within mountain biodiversity hotspots experi-enced lower loss rates than their surroundings.Increasing the area of protection in mountains should becentral to preserving montane forests and biodiversity in the future.INTRODUCTIONextinction.Unfortunately,forest loss and degradation posesignificant threats to the persistence of forest-dwelling speciesMountains are vital to the world's terrestrial biodiversity.asthat rely on specific microenvironments worldwide.4 In addi-they provide habitat to more than 85%of the world's bird,tion,climate change is forcing many montane species tomammal,and amphibian species.'Montane forests serve asmove to higher elevations in search of suitable habitats,5.6important refuges for large numbers of rare and endangeredbut their ability to do so is potentially limited by topographicspecies with small geographic distributions,making themconstraints and the integrity of the habitat.?Understandingrepresent regions of high conservation significance.2 Asthe dynamics of mountain forest loss worldwide is thereforemany montane species have narrow ranges,even relativelycrucial for predicting and mitigating the potential impacts onsmall reductions in forest habitat may increase their risk ofsensitive forest species.One Earth 6,303-315,March 17,2023 2023 Elsevier Inc.303