Soil fauna accelerate litter mixture decomposition globally, especially in dry environments. (25th January 2022)

• Record Type: Journal Article
• Authors: Njoroge, Denis Mburu; Chen, Si‐Chong; Zuo, Juan; Dossa, Gbadamassi G. O.; Cornelissen, Johannes H. C.
• Is Part Of: Journal of ecology. Volume 110:Number 3(2022)
• Page Start: 659
• Page End: 672
• Publication Date: 2022-01-25
• Subjects: biodiversity -- drought -- ecosystems functions -- global analysis -- litter decomposition -- litter mixture effect -- nutrient cycling -- soil fauna; Plant ecology -- Periodicals; 577.05
• DOI: 10.1111/1365-2745.13829
• Languages: English
• ISSNs: 0022-0477

Abstract

Abstract: More than half of the net primary production in terrestrial ecosystems returns to the soil through leaf litter fall and decomposition. In terrestrial ecosystems, litter constitutes a mixture of mainly senescent foliage from multiple species. Yet, the effect of litter mixing on litter decomposition rate remains ambiguous. Quantification of the soil fauna contribution and inclusion of their interaction with litter could remove the prevailing ambiguity, as soil fauna might influence the direction and magnitude of litter mixture effects on decomposition. We carried out a global meta‐analysis to elucidate how soil fauna influenced litter mixture decomposition rate based on 55 published studies with 873 fauna inclusion/exclusion observations in field litterbag experiments. We hypothesized that soil fauna inclusion in litter mixture experiments would cause a positive change in the magnitude of mixed litter decomposition. That is, the presence of soil fauna would lead to synergistic litter mixture effects while the absence of soil fauna would lead to antagonistic litter mixture effects. Furthermore, we hypothesized that soil fauna would have a greater positive impact on the litter mixture effect in environments with low precipitation. While litter mixture had a neutral effect on decomposition on average across studies, non‐additive mixture effects were common, with a key role for soil fauna, which generally enhanced decomposition rate compared to the component single‐species litters. In contrast, fauna exclusion resulted in diminished decomposition rate overall. The overall synergistic soil fauna effect on litter mixture decomposition increased under low precipitation. Under high precipitation, the litter mixture effect was positive in the absence of soil fauna but non‐significant in the presence of fauna. Climate imposes a great effect on litter mixture, with synergistic effects increasing towards the equator. Synthesis . These results highlight the importance of soil fauna in mixed litter decomposition, most strongly in dry environments. In this era of global climate change, where some regions are projected to become drier, soil fauna might compensate the expected slower decomposition of litter by increasingly enhancing litter mixture decomposition. Abstract : Our study results highlight the importance of soil fauna in mixed litter decomposition, most strongly in dry environments. In this era of global climate change, where some regions are projected to become drier, soil fauna might compensate the expected slower decomposition of litter by increasingly enhancing litter mixture decomposition. 摘要: 陆地生态系统中大部分净生产量通过凋落物分解过程返回土壤。生态系统中叶片凋落物来自不同物种并混合存在，但凋落物分解的混合效应仍不明确。土壤动物对凋落物分解具有调控作用，量化分解过程中土壤动物的作用及其与凋落物的交互作用对全面认识混合凋落物分解过程具有重要意义。 我们基于全球55篇已发表的研究开展整合分析（Meta‐analysis），探讨土壤动物如何影响混合凋落物的分解速率。我们假设有土壤动物参与分解会正向改变混合凋落物的分解速率，即土壤动物的参与会导致混合凋落物的协同效应，没有土壤动物参与则会导致混合凋落物的拮抗效应。我们提出进一步假设，土壤动物的作用会随环境改变，在降雨量较少的环境中土壤动物对凋落物混合效应的作用会增大。 凋落物混合效应总体上呈现加和效应，但在有土壤动物参与的情况下混合凋落物质量损失高于各组分凋落物质量损失。而在排除土壤动物影响的情况下，凋落物的质量损失总体上出现降低。土壤动物对混合凋落物分解的影响随着降雨量的减少而增强。在降雨量较大的情况下，排除土壤动物参与分解的凋落物具有正向的混合效应，有土壤动物参与的情况下凋落物混合效应不显著。气候可对混合凋落物分解产生影响，混合凋落物之间的协同效应在热带地区更高。 研究表明，土壤动物对混合凋落物分解具有重要作用，此作用在干旱环境中尤为明显。在全球气候变化下，土壤动物可能可以调节因干旱导致的混合凋落物分解的改变。