Trophic niche variation in springtails across soil depth

作者：Jing‐Zhong Lu, Melissa Jüds, Linlin Zhong, Johannes Lux, Stefan Scheu, Amandine Erktan · 发表于：European Journal of Soil Biology · 年份：2025 · DOI：10.1016/j.ejsobi.2025.103745 · 被引用次数：3 · 研究领域：Isotope Analysis in Ecology、Species Distribution and Climate Change、Rangeland and Wildlife Management

Soil invertebrates move vertically through the soil to forage and avoid environmental stress. However, how their diet shifts with depth remains poorly understood, limiting our understanding of their trophic plasticity. Trophic consistency across depths could result from similar trophic niches existing at the microscale within different soil layers (the micro-scale feeding hypothesis). To test this, we conducted a microcosm experiment incubating springtails ( Ceratophysella denticulata ) in six separate forest soil layers (O L , and O F/H , and 0–3, 3–6, 6–9 and 9–12 cm depth of the mineral soil) and analysed changes in Collembola stable isotope ratios ( 13 C/ 12 C, 15 N/ 14 N). As expected, 13 C/ 12 C and 15 N/ 14 N ratios in litter and soil organic matter increased with depth, whereas 13 C/ 12 C ratios of Collembola did not significantly differ across layers suggesting consistent basal resource use supporting the micro-scale feeding hypothesis. By contrast, 15 N/ 14 N ratios of Collembola increased with depth, following the trend of organic matter from O L to 0–3 cm soil, but not beyond. These results suggest that carbon and nitrogen nutrition of springtails is decoupled, and that the use of litter to calibrate 15 N/ 14 N values for estimating trophic positions of soil animals requires careful interpretation. Our results highlight the importance of soil depth as determinant of trophic positions of soil animals and point to principle differences in nitrogen resource acquisiti...