Data associated to the paper: Detritivory to microbivory shift in soil invertebrates with decreasing litter quality (Tsurikov et al.)

Soil fauna regulate litter decomposition and carbon redistribution in soil, acting as both litter and microbial feeders. However, whether these feeding roles shift along environmental gradients remains unclear. We tested whether microbivory increases in cold climates and with lower litter quality – both factors limiting detritus digestion by fauna. Using stable isotope composition (<i>δ</i>¹³C, <i>δ</i>¹⁵N) of 7,263 soil invertebrate samples across temperate and tropical forests, we found that litter carbon percentage positively correlated with trophic level, indicating higher microbivory in low litter quality systems. This effect was more evident in mesofauna, while macrofauna showed an ability to incorporate more recalcitrant plant carbon. Climate type had no general effect on feeding strategies. Our findings suggest low litter quality shifts soil animals from detritivory to microbivory, highlighting the importance of litter quality over climate in shaping soil food webs. Understanding these shifts is crucial for predicting litter decomposition and global carbon cycling

土壤动物群调控土壤枯落物分解与碳再分配过程，同时兼具枯落物取食者与微生物取食者的双重生态功能。然而，这类取食功能是否会随环境梯度发生转变，目前仍未明确。我们针对寒冷气候以及低品质枯落物环境下动物的微生物取食行为是否会增强这一假说开展验证——上述两类因素均会限制动物对腐殖质的消化效率。本研究依托温带与热带森林中7263份土壤无脊椎动物样本的稳定同位素组成（δ¹³C、δ¹⁵N）开展分析，结果显示枯落物碳含量与营养级呈显著正相关，表明在枯落物品质较低的生态系统中，动物的微生物取食比例更高。该效应在中型土壤动物（mesofauna）中表现更为显著，而大型土壤动物（macrofauna）则能够利用更多难降解植物碳源。气候类型对动物的取食策略未产生普遍影响。本研究结果表明，低品质枯落物会促使土壤动物从腐食性转向微生物取食性，凸显了枯落物品质相较于气候在塑造土壤食物网过程中的重要性。明晰这类取食功能的转变，对于预测枯落物分解过程与全球碳循环至关重要。