Foundation species has the significant effect of increasing the complexity of structure within the ecosystem. In forest ecosystems, epiphytes are the secondary foundation species that establish on the primary foundation species (trees), and provide diverse and abundant habitats for forest inhabitants on trees. Therefore, arthropods on trees would be predicted to differ in species and abundance depending on epiphyte density within forests, and to benefit strongly from epiphytes in forests with lower forest floor availability. In this study, we used ants to examine whether the effects of epiphytes on arthropods in wetland forests extend to the forest scale. We collected ants using bait traps on tree trunks and on the forest floor in subtropical wetland forests with varying densities of bird’s nest ferns. We, also collected them on epiphytes at sites with high epiphyte densities. Our results showed that 12 ant species were collected throughout the wetland forests. Ants appeared more frequently on epiphytes than on tree trunks, and more frequently with increasing epiphyte size. The frequency of ant occurrence did not vary with the epiphyte density between stands. However, the indicator ant species differed depending on the density of epiphytic plants, and the frequency of occurrence of each species differed.Our results suggests a local effect of epiphytes on ant activity. Higher epiphyte densities influenced species assemblage, although there was no detectable effect on ant activity.