Data for the article: Trophic positions of soil microarthropods in forests increase with elevation, but energy channels remain unchanged

<p><span>Mountain forests are at risk as the consequences of climate change will likely lead to altered tree species boundaries. Characterizing food webs along elevational gradients in primary forests may help to predict potential consequences of such changes. The soil food web provides nutrients to plants through decomposition of dead organic matter. Changes in the soil food web with elevation are poorly characterized and most studies focus on community composition of microbes and individual arthropod taxa. </span><span><span> </span></span><span>Here, for the first time we studied trophic variations in two of the species rich microarthropod taxa, Collembola and Oribatida, along an elevational gradient of primary forest in Northeast China, Changbai Mountain. </span><span>Samples were taken at seven elevations of 150 m elevational difference between 800 and 1700 m. At each elevation eight subplots were established and Collembola and Oribatida were extracted from litter samples. </span><span><span> </span></span><span>We applied three state-of-the-art methods to elucidate trophic positions and basal resource use of both taxa at community level: b<span>ulk stable isotope analysis of nitrogen and carbon (SI_bulk), compound-specific stable isotope analysis of amino acids (CSSIA-AA) and dietary routing through neutral lipid fatty acids (NLFA).</span></span><span><span> </span></span><span>Δ</span>^{<span>15</span>}<span>N_bulk and trophic position calculated using CSSIA-AA (TP_CSSIA) both increased with elevation in both taxa. Stable isotope mixing models</span><span> using δ¹³C of essential amino acids indicated saprotrophic fungi as most important resource at most elevations for both taxa. Also, proportions of marker NLFAs changed little across elevations in both taxa, however, in Collembola the contribution of bacterial markers was generally higher than in Oribatida. Δ</span>^{<span>13</span>}<span>C_bulkdid not respond linearly to the elevational gradient; however, changes with elevations differed between Collembola and Oribatida. A strong linear relationship between </span><span>δ</span>^{<span>15</span>}<span>N of phenylalanine in consumers and</span><span> δ</span>^{<span>15</span>}<span>N of litter indicated litter as basal resource of both taxa. </span><span>Overall, the results suggest that food web functioning likely changes with changing forest types along elevational gradients with microarthropods switching from feeding at the base of the food web to feeding at higher trophic levels potentially compromising their role in litter decomposition and nutrient cycling.</span></p>