Abstract
Litter trapped in epiphytic ferns (Asplenium nidus L.) and their rootballs were sampled for arthropods and compared with the forest floor (soil and litter) in a Japanese subtropical forest. A total of ca 40,000 individuals were identified to species, representing 13 arthropod groups and 553 species. The densities (numbers per 100g dry wt of substrate) of the five most abundant taxa (Oribatida, Mesostigmata, Collembola, Coleoptera, Formicidae) were generally higher in the fern habitats (trapped litter and roots) than in the forest-floor habitats (soil and litter). From the 553 species, 267 were collected from bird's nest ferns and 403 from the forest floor. Rarefaction curves indicate that for a same number of individuals collected, species richness was at least twice higher on the forest floor than in the ferns for four of the five most diverse groups (Oribatida, Mesostigmata, Coleoptera, Collembola) whereas Araneae had slightly more species in ferns. Multivariate ordination showed that overall species composition clearly differed between fern habitats and the forest-floor habitats. Although species richness in bird's nest ferns may not be as high as for the forest floor, our study supports the hypothesis that these epiphytes are important reservoirs of arthropod biodiversity.
