In the canopies of Monteverde, Costa Rica, a network of orchids, ferns, and other epiphytes—the nonparasitic plants that grow on the tree’s branches—play a key role in the rainforest water cycle.
Under normal circumstances, moisture shouldn’t be a problem for plants in Monteverde, as the region has historically received more than 100 inches of rain per year. Unfortunately, the number of dry days has quadrupled from 25 to more than 110 since the 70s.
Todd Dawson, a professor in the Departments of Environmental Science, Policy, and Management and Integrative Biology, is part of a collaborative team of tree physiologists and ecohydrologists studying the outsized role of epiphytes in moving water through tropical forests. Over the last decade, their fieldwork and experiments have uncovered that rainforest epiphytes will be the first plants to die in a hotter, less predictable climate.
Dawson and other collaborators are currently working on a project that involves climbing into Monteverde’s canopy and removing the epiphytes clinging to the trees. The removal simulates climate change's effects on the rainforest, offering a window—and a warning—of the fragility of forest ecosystems in Costa Rica and around the world.
“I think of the epiphytes as part of the fabric of the entire ecosystem,” Dawson told the Proceedings of the National Academy of Sciences (PNAS). “If you remove the epiphytes, you’re unweaving the fabric.”
Read more about their research in PNAS, and watch a short film about the importance of epiphytes below.