Note: this post is one of dozens written by students participating in a 2015 field course in Costa Rica. The entire series is here.
Rainforests are among the richest biomes on the planet. We have observed this first hand on our daily excursions as we collect insects and search for plants. However, there are also pressures being placed on the environment that threatens the diversity within the rainforest.
During the first few days of our stay in Monteverde, our group listened to a lecture by Dr. Alan Pounds of the Monteverde Cloud Forest Reserve. Dr. Pounds first came to Monteverde because of his interest in herpetology but as time passed, his research shifted from herpetology to climate change, spurred by the extinction of the golden toad, Bufo periglenes, a species that was once endemic to Monteverde. The last individual was recorded in 1989 and the species has since been declared extinct. A number of other amphibians also vanished from the area around the same time, including many species of harlequin toads, from the genus Atelopus.
This mass extinction of amphibians may be attributed to a type of chytrid fungus called Batrachochytrium dendrobatidis. The fungus can be spread between individuals through their skin. And because amphibians breath through their skin, the fungus inevitably suffocates the individual. The B. dendrobatidis outbreak that had killed so many amphibians may have been spurred by climate change but more research is required to fully understand the cause of the mass extinction.
Further readings: Pounds, J. A., Bustamante, M. R., Coloma, L. A., Consuegra, J. A., Fogden, M. P., Foster, P. N., ... & Young, B. E. (2006). Widespread amphibian extinctions from epidemic disease driven by global warming. Nature, 439(7073), 161-167.