Distribution of Arboreal Acarofauna in Two Species of Tropical Trees

ABSTRACT We investigated vertical stratification of mite communities (Oribatida, Mesostigmata, and Prostigmata) along tropical tree architecture in Cát Tiên National Park, Vietnam. We examined two phylogenetically unrelated but architecturally similar tree species, Haldina cordifolia and Dipterocarpus alatus ; both are tall trees with straight cylindrical trunks, fissured bark, spreading crowns, and large leaves. To investigate potential interaction between sampling method and observed ecological patterns, we compared two methods—Tullgren–Berlese and substrate washing—for extraction of mites from tree bark. Across forest floor and arboreal samples, we identified 140 species of Oribatida, 70 species of Mesostigmata, and 57 species of Prostigmata. Numerically, arboreal acarofauna was dominated by Oribatida. Tree species identity did not influence total mite species richness, community composition of all Acari and Oribatida, or Oribatida abundance. Mesostigmata and Prostigmata were more abundant on H. cordifolia . Microhabitat had a significant effect on the abundance of arboreal Mesostigmata and Prostigmata but not Oribatida, and on species richness and community composition of arboreal acarofauna, with certain species restricted to specific tree zones irrespective of tree species. Assemblages formed three clusters: communities of (i) soil, litter, and trunk base, (ii) bark on upper trunk, and (iii) canopy branches and leaves. Substrate washing yielded higher abundances of Oribatida and Prostigmata and a higher number of detected species than Tullgren–Berlese extraction, with each method capturing a different species assemblage. To avoid bias, a complementary combination of methods is recommended for comprehensive assessment of arboreal mite biodiversity.