Epiphytes Article Preview

Written by: Caroline Kim

October 29, 2022

Today, we’ll dive into the article “Epiphyte response to drought and experimental warming in an Andean cloud forest” by Miles R. Silman and Joshua M. Rapp. Epiphytes are a unique way in which plants grow on another plant, are not parasitic, and have no contact to the ground (Petruzzello). Due to their unique nature, most grow in tropical ecosystems that provide plenty of moisture, nutrients, and sunlight (Petruzzello). Tropical Montane Forests (cloud forests) pair well with epiphytes due to the nutrients cycling and nurturing of biodiversity; in fact, “epiphytes are considered indicator species in cloud forests for changing water balance conditions” (Rapp).

With that in mind, in these cloud forest regions, atmospheric conditions are expected to change with climate change, but are harder to predict. A concern for these cloud conditions include elevated base height of clouds, which has had detrimental effects in Costa Rica, where there was a much higher leaf mortality; this can’t quite be generalized to the Andes though, which may have higher resistance due to being in more variable conditions instead of a more localized cloud forest (Rapp). The two research questions considered by Rapp and Silman were the resulting demographic changes from being moved from their normal elevation and is this effect more definitive in down-slope/warmer/drier conditions (such as Costa Rica) (Rapp). Specific data and procedures for the experiment is detailed in the article (link on the home page).

After concluding the experiment, the researchers discovered that “... warmer temperatures and lower cloud immersion will cause community-level changes for species currently above the cloud base” (Rapp). Additionally they discovered how regionally, the plant responses differed: “The response to transplanting was strongest in those transplanted from the highest elevation, which is coolest and has the highest degree of cloud immersion. Epiphytes from lower elevations only benefitted slightly from increased water availability and cooler temperatures, possibly indicating they are better adapted to withstand heat and drought stress” (Rapp). Surprisingly, there was a decent resistance to transplant-induced moisture stress due to competing factors of sufficient rainfall and tolerance from varying conditions (Rapp). The researchers concluded that dry seasons may in fact be beneficial for building up tolerance in epiphytes. They do mention that it is important to still be aware of the impact epiphytes have on the environment and how disruption can impact the entire ecosystem (Rapps).

Sources:

Rapp JM and Silman MR. Epiphyte response to drought and experimental warming in an Andean cloud forest [version 2; peer review: 2 approved]. F1000Research 2014, 3:7 (https://doi.org/10.12688/f1000research.3-7.v2)

Petruzzello, Melissa. "epiphyte". Encyclopedia Britannica, 12 Mar. 2020, https://www.britannica.com/plant/epiphyte. Accessed 30 October 2022.