Authors: Eileen Helmer*, USDA Forest Service - International Institute of Tropical Forestry, Elizabeth A Gerson, Ecological Research Support, Thomas S Ruzycki, Center for Environmental Management of Military Lands, Colorado State University, L. Scott Baggett, USDA Forest Service Rocky Mountain Research Station
Topics: Global Change, Mountain Environments, Land Use and Land Cover Change
Keywords: cloud forest, tropical montane forest, climate change, fog, deforestation
Session Type: Virtual Poster
Start / End Time: 11:10 AM / 12:25 PM
Room: Virtual 51
Presentation File: Download
Tropical montane cloud forests (TMCF) and páramo are among the most biodiverse ecosystems on Earth. Unique species evolved in both as persistent cloud immersion created isolated habitats on mountaintops. Studies suggest climate change will reduce cloud immersion in some TMCF but increase it elsewhere. Increased land surface temperatures could make air travel further up mountains before it cools enough to form clouds. Alternatively, increased humidity over warming oceans might increase cloud immersion.
We developed a new empirical approach combining relative humidity (RH), frost, and maximum watershed elevation, to project change in TMCF and páramo for Representative greenhouse gas emissions Concentration Pathways (RCPs).
We found that climate change would increase cloud immersion for only about 1% of Neotropical TMCF and in only a few places. Declines in cloud immersion dominate. Most TMCF shrink (from clouds forming at higher elevations), and dry, with RH declines suggesting fewer or thinner clouds. In as few as 25 years, climate change would shrink and dry 60-80% of Neotropical TMCF. With RCP 4.5, half of Neotropical cloud forest ecoregions experience cloud immersion declines comparable to where studies link upward species migrations to climate change. Under RCP 8.5, 90% of them are impacted by 2060, and 90% of páramo would disappear. TMCF are ~85% forested overall, but some TMCF least affected by climate change are most deforested or least protected. Climate change may pose a risk to species over areas at least as extensive as those affected by land use, regardless of future land cover.