Diversity, Phylogeny and Trophic Ecology of Arboreal Collembola Communities along a Lowland Rainforest Transformation Gradient
Collembola are micro‐arthropods which play a vital role in the leaf litter decomposer system and the formation of humus soil. In the Asian tropics, Collembola are unusually abundant on tree crowns. Dominated by the families Entomobryidae and Paronellidae, they are likely key elements to the formation of soil‐filled microhabitats on tree crowns, leaf axles and epiphytic ferns. Studying the arboreal Entomobryidae and the Paronellidae along a transformation gradient from rainforest via extensive jungle rubber to monocultures of rubber and oil palm, we aim to learn about the degree and the pathways in which agricultural systems retain the ability to form humus soil. Specifically, we plan three lines of work: morphological taxonomy, molecular phylogeny and biodiversity analysis, and food web analysis via stable isotopes and fatty acids. A collection of 39.691 specimen from the dry season 2013 collection has been assigned to 38 morphospecies, and taxon expert revision is currently taking place. Our preliminary analysis suggests that springtail species richness in forest and jungle rubber is significantly higher than in rubber or oil palm monocultures, while species diversity is similar (Figure 1). Simultaneously, community composition differs significantly between the land use systems (Figure 2), with rainforest and jungle rubber communities being much more similar in themselves and with each other, than communities inhabiting rubber and oil palm monocultures. We have a manuscript focusing on the effects of land use change on Collembola species richness, diversity and community composition in preparation, and photographic documentation of morphospecies is in progress (Fig. 2). Future analytical directions include molecular approaches to resolve arboreal collembola phylogeny and stable isotope measurements to detect dietary shift.
Figure 1. Community measures of arboreal springtails (Collembola) in rainforest (F), rungle rubber (J), rubber (R) and oil palm plantations (O) in Jambi Province. We calculated (a) average species richness Nsp and inverse Simpson diversity 1/D and compared averages with ANOVA followed by pairwise t-tests using Holm’s correction. Different letters indicate significant differences (all p<0.0001). We then used DFA ordination (b) to analyse community composition. P-values below α=0.05 indicate a significant discrimination between communities of different land use systems.