DOI: 10.5061/dryad.5tb2rbp6b
title: Species matrix of Indonesian litter and soil Collembola with environmental factors

description: Collembola are among the most abundant and diverse microarthropods that
 affect litter decomposition, control microbial functioning and support
 invertebrate predators. Rainforest conversion and expansion of plantations
 in tropical regions are associated with changes in microclimate and
 biodiversity decline, but information on the impact of tropical land use
 on Collembola communities and their seasonal fluctuations is very limited.
 Here, we investigated seasonal fluctuations in density and community
 composition of Collembola in rainforest, and in rubber and oil palm
 plantations in Jambi province (Sumatra, Indonesia), a region with moderate
 seasonality (wet and dry seasons) that experienced one of the strongest
 deforestations globally during the last decades. Samples were taken at the
 end of the wet season (March), the beginning of the dry season (June), the
 end of the dry season (August) and the beginning of the wet season
 (November). Collembola density in the litter was at a maximum at the
 beginning of the wet season, whereas in soil it generally varied little.
 Densities of euedaphic (soil-adapted) and epedaphic species (upper
 litter-adapted) fluctuated less with season than hemiedaphic (lower
 litter-adapted) and atmobiotic species (aboveground-adapted). Collembola
 community composition changed with season in each of the land-use systems,
 with the differences being more pronounced in litter than in soil.
 Differences in community composition among all three land-use systems were
 most pronounced at the beginning of the dry season. Water content, pH,
 fungal and bacterial biomarkers, C/N ratio and root biomass were
 identified as factors related to seasonal variations in species
 composition of Collembola in different systems. Our results show that
 Collembola density and community composition often fluctuate in a similar
 way across land-use systems, indicating that they are driven by common
 environmental factors, with water content, pH and food availability being
 of prominent importance. Notably, differences in Collembola community
 composition between rainforest and plantation systems were most pronounced
 in the dry season (June, August), indicating that the conversion of
 rainforest into plantation systems aggravates detrimental effects of low
 moisture on soil animal communities. Fluctuations in Collembola
 communities were generally stronger in litter than in soil, reflecting
 that Collembola in litter are less buffered against climatic variations
 than those in soil. Overall, the results document the sensitivity of
 tropical soil animal communities to seasonal climatic variations, which
 intensifies the effects of the conversion of rainforest into plantation
 systems on soil biodiversity.
description: Samples were taken within 50 m x 50 m plots established at each
 study site with minimum distance of 500 m, but usually more than 1 km
 between plots. Each land-use system was replicated four times resulting in
 a total of 12 plots (3 land-use systems x 4 replicates). From each plot at
 each sampling date, one randomly positioned sample was taken resulting in
 48 soil cores in total. Each sample measured 16 cm x 16 cm taken to a
 depth of 5 cm of the mineral soil. Litter and soil were separated in the
 field and processed separately (96 samples in total). Then, samples were
 transported to the laboratory for extraction of soil animals. Animals were
 extracted by heat for 4–8 days until the substrates were completely dry 
 and stored in 70% ethanol until further processing. Environmental
 variables were measured in composite samples of each litter and soil (five
 cores per plot within a radius of ca. 2 m around the soil animal sample),
 including abiotic factors (pH, water content, C/N ratio) and biotic
 factors (microbial community composition in litter and soil as indicated
 by phospholipid fatty acids) including the sum of phospholipid fatty acid
 (PLFA) marker/relative marker lipids of Gram-positive bacteria (i15:0,
 a15:0, i16:0, i17:0), Gram-negative bacteria (2OH 12:0, 2OH 14:0,
 16:1ω7, cy17:0, 2OH 16:0,
 cy19:0, 2OH 10:0), fungi (18:2ω6,9), algae (20:5ω3), arbuscular mycorrhizal fungi
 based on the neutral lipid fatty acid (NLFA) 16:1ω5c and root biomass.
 Litter and soil pH (CaCl2) was measured using a digital pH meter
 (Greisinger GPHR 1400A, Regenstauf). Aliquots of litter and soil material
 were dried at 65°C for 72 h, milled and analyzed for total C and N
 concentrations using an elemental analyzer (Carlo Erba, Milan, Italy).
 Water content (Wet weight, proportion of dry weight) of litter and soil
 were determined gravimetrically. Collembola were sorted
 into morphological groups under a dissecting microscope (Stemi 508, Zeiss,
 Jena, Germany) at 50x magnification based on basic morphological
 characters (body shape, morphology of furca, antennae, number of eyes).
 Several individuals of each morphological group from each sample were
 subsequently cleared with Nesbitt solution on a heating plate
 (50<sup>⁰</sup>C) for 3-10 min. Then, the animals were mounted
 on slides with Hoyer’s solution. Collembola were identified to species
 level using a compound microscope (Axiovert 35, Zeiss) at maximum 400x
 magnification using the checklist for Indonesian Collembola  and
 additional articles containing keys for Collembola of southeast Asia,
 particularly Indonesia