Suspended soils in forest canopies are thought to harbor a substantial fraction of canopy biomass and many arboreal specialists, but do forest floor generalist predators with high vagility also use this habitat? We tested the hypothesis of no difference between forest floor and suspended-soil predatory mite faunas (Acari: Mesostigmata) in an Australian rain forest. Our results show that instead of being habitat generalists, many predatory mites partition soil into two main strata: soil suspended aboveground irrespective of height (0.5-20m) and soil on the ground. Of 53 species of Mesostigmata in suspended soil, 53 percent (28 species) were absent from or rarely found on the ground. This increased to 60 percent (15/25 species) if only common species are considered. Among these 15 'suspended-soil specialists', all but the three least abundant were found throughout the arboreal strata. Moreover, ten species also occurred in litter accumulated on the surface of decaying logs or boulders close to the forest floor. Thus, although the arboreal predatory mite fauna is distinct from that on the forest floor, it is not restricted to the high canopy: even slightly elevated substrate appears acceptable as habitat for these suspended-soil specialists. Our data suggest that a substantial portion of a rain forest's soil and litter fauna is held above the forest floor. © 2010 The Author(s). Journal compilation © 2010 by The Association for Tropical Biology and Conservation.

The Canopy Starts at 0.5 m: Predatory Mites (Acari: Mesostigmata) Differ between Rain Forest Floor Soil and Suspended Soil at any Height

We developed a novel protocol with superior quantitative analysis results for DNA metabarcoding of Collembola, a major soil microarthropod order. Degenerate PCR primers were designed for conserved regions in the mitochondrial cytochrome c oxidase subunit I (mtCOI) and 16S ribosomal RNA (mt16S) genes based on published collembolan mitogenomes. The best primer pair was selected based on its ability to amplify each gene, irrespective of the species. DNA was extracted from 10 natural communities sampled in a temperate forest (with typically 25–30 collembolan species per 10 soil samples) and 10 mock communities (with seven cultured collembolan species). The two gene regions were then amplified using the selected primers, ligated with adapters for 454 technology, and sequenced. Examination of the natural community samples showed that 32 and 36 operational taxonomic units (defined at a 90% sequence similarity threshold) were recovered from the mtCOI and mt16S data, respectively, which were comparable to the resu...

A quantitative protocol for DNA metabarcoding of springtails (Collembola).

Asplenium bird's nest ferns in rainforest canopies are climate-contingent refuges for frogs

In tropical forests, epiphytes increase habitat complexity and provision services rare to canopy environments, such as water retention, nutrient cycling, and microclimate refuge. These services facilitate species diversity and coexistence in terrestrial ecosystems, and while their utility in forest ecosystems is appreciated for the Bromeliaceae of the Neotropics, fewer studies have examined the role of Paleotropic epiphytes in ecological niche theory. Here, we compare herpetofaunal presence, abundance, and diversity of in bird’s nest fern (Asplenium nidus complex; BNF) to other microhabitats in Madagascar and the Philippines. We measure BNF fern microclimates, examine temporal use of canopy microhabitats, and test models of fern characteristics hypothesized to predict herpetofaunal use. In both countries, one in five BNFs were occupied by herpetofauna, mostly amphibians, and species using BNFs were highly dissimilar from those in other microhabitats. Herpetofaunal presence and abundance were greater in BNFs than in other canopy microhabitats and were most commonly used during the day when fern temperatures were highly buffered. Finally, BNF area was the best predictor of herpetofaunal presence and abundance, compared to canopy cover and BNF height. Importantly, these patterns remained consistent despite the distinct phylogenetic histories of our two communities (Asian versus African). Our results suggests that BNFs and their microclimate services play a critical role in the ecology of two Paleotropic forests, and facilitate the use of canopy habitats by climate-sensitive species. However, future studies are needed to assess the consistency of BNFs’ utility as a microclimate refuge across their large range.

Bird's nest fern epiphytes facilitate herpetofaunal arboreality and climate refuge in two paleotropic canopies.

Distributional data for the millipedes occurring in the Ryukyu Archipelago and adjacent islets (Senkaku and Daito Groups) are summarized based on an extensive literature survey. There are at least 58 species and one subspecies of millipedes known from the Ryukyu Archipelago (50 of these are native and 8 introduced), 5 species in the Senkaku Group, and 7 species in the Daito Group. Of these, the greatest diversity of indigenous millipede species (32 species) occurs in Okinawa-jima Island. Our results contribute to the knowledge of the millipede fauna in the region beyond the limited account presented in the previous reviews. The results also suggest that large portions of the Ryukyu Archipelago have been poorly sampled, and that further collections would considerably improve the present inventory.

Distribution and diversity of millipedes of the Ryukyu Archipelago, with the Senkaku and Daito Island Groups: A literature review (Arthropoda: Diplopoda)

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 100 g 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 12 Shigenori Karasawa et al. 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.

Yasuhiko Suma

Papers

Bird's nest ferns as reservoirs of soil arthropod biodiversity in a Japanese subtropical rainforest

Classification of the Suborder Neelipleona Massoud, 1971 and Symphypleona Borner, 1901 (Hexapoda: Entognatha: Collembola) from Japan