Epiphytes are important for canopy dwelling organisms because they provide a cool and
moist microhabitat in the relatively hot and dry canopy. Here we examine whether epiphytic Asplenium ferns act as important habitats for arboreal frogs. We conducted extensive fern and habitat surveys for frogs in the Philippines, and complimented these surveys
with roaming day and night canopy surveys to identify the full extent of habitat use across
the vertical strata. We artificially dried ferns of various sizes to identify relationships between water and temperature buffering. Ferns are the preferred diurnal microhabitat and
breeding habitat for arboreal frogs. A strong positive relationship exists between fern size
and frog usage and abundance. Our drying experiments show that large ferns buffer maximum temperatures and reduce variability in temperatures, and buffering is directly linked
to their hydration. Frogs are likely using large ferns for their moist, cool, environments for
breeding and daytime retreat, which supports the buffered microhabitat hypothesis—these
plants promote species coexistence through habitat creation and amelioration of physical
stress. However, drying experiments suggest that this buffering is contingent on regular
rainfall. Altered rainfall regimes could lead to the unexpected loss of the functional capacity of these important fern habitats