Abstract

Litter decomposition in most terrestrial ecosystems is regulated by moisture-dependent microorganism activity, among other things. Decomposition models typically underestimate rates of plant litter decomposition in drylands, suggesting the existence of additional drivers of decomposition. Attempts to reveal these drivers have predominantly focused on abiotic degradation agents, alternative moisture sources, and soil–litter mixing. The role of burrowing animals in promoting decomposition has received less attention despite greatly contributing to plant litter transfer from the harsh desert surface to the moister and nutrient-rich environment belowground. Our goal was to explore how macro-detritivore burrows affect plant litter mineralization dynamics. We introduced ¹³C-labeled litter belowground into (1) desert isopod (Hemilepistus reaumuri) burrows and (2) artificial burrows, and aboveground on top of (3) isopod fecal pellet mounds and (4) bare soil crust. We compared the litter mass loss between the four treatments and used cavity ring-down spectroscopy to reveal the in situ mineralization dynamics. No litter mineralization was evident during the dry summer months both above- and belowground. Following rain events, mineralization rates spiked in all four micro-environments, quickly diminishing aboveground while slowly waning belowground. Total litter mass loss was twofold higher below than aboveground and was significantly higher in isopod burrows compared to artificial burrows. Our findings demonstrate that burrowing macro-detritivores promote litter decomposition in deserts by transferring organic matter to their burrows where favorable climatic conditions and a nutrient-enriched environment foster microbial activity. Thus, attempts to resolve the dryland decomposition conundrum should not be limited to exploring factors that allow decomposition under harsh desert surface climatic conditions, but focus on the role that animals play in facilitating decomposer-friendly environments to which they translocate plant litter.

Graphical abstract

中文翻译：

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宏观破坏者通过为分解者设计地下天堂来协助解决旱地分解难题

摘要

除其他事项外，大多数陆地生态系统中的凋落物分解受水分依赖性微生物活动的调节。分解模型通常会低估干旱地区植物凋落物分解的速率，表明存在分解的其他驱动因素。揭示这些驱动因素的尝试主要集中在非生物降解剂，替代水分源和土壤-废弃物混合方面。尽管穴居动物在促进分解中的作用尽管引起植物凋落物从恶劣的沙漠表面转移到地下潮湿和养分丰富的环境中，却很少受到关注。我们的目标是探索宏观破坏洞穴如何影响植物凋落物矿化动力学。我们介绍了¹³地下有C标签的垃圾进入（1）沙漠等足动物（Hemilepistus reaumuri）洞穴和（2）人工洞穴，并在（3）等足类粪便土堆和（4）裸露的土壤地壳之上。我们比较了四种处理之间的垫料质量损失，并使用腔衰荡光谱法揭示了原位矿化动力学。在地下和地下的干燥夏季，没有明显的垃圾矿化现象。降雨后，四个微环境中的矿化率均达到峰值，在地上迅速减小，而在地下则逐渐减弱。与人工洞穴相比，等足类洞穴的总凋落物质量损失低于地下的两倍，并且显着更高。我们的研究结果表明，穴居大型杀虫剂通过将有机质转移到其有利于气候条件和营养丰富的环境促进微生物活动的洞穴中来促进沙漠中的凋落物分解。因此，解决旱地分解难题的尝试不仅限于探索在恶劣的沙漠表面气候条件下允许分解的因素，而应侧重于动物在促进易分解者的环境中所发挥的作用，使植物凋落物易位。

图形概要