Soil Microbial Community and Litter Quality Controls on Decomposition Across a Tropical Forest Disturbance Gradient
Soil Microbial Community and Litter Quality Controls on Decomposition Across a Tropical Forest Disturbance Gradient
复制标题
热带森林干扰梯度下土壤微生物群落和凋落物质量对分解的控制
DOI：
10.3389/ffgc.2020.00081
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发表时间：
2020-07-16
影响因子：
3.2
通讯作者：
McNamara, Niall P.
中科院分区：
文献类型：
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作者：
Elias, Dafydd M. O.;Robinson, Samuel;McNamara, Niall P.
工业伐木和农业扩张正在推动热带生态系统的快速转变，改变地上植物和地下微生物群落的模式。然而，生物多样性的这些变化在多大程度上驱动了生态系统过程速率的改变，如凋落叶分解，人们知之甚少。为了确定凋落物化学质量的变化和微生物分解者的变化对凋落物分解速率的相对影响，我们在热带土地利用扰动梯度下进行了一个受控的、互惠移植的凋落物分解实验。从马来西亚沙巴的老生林、中度采伐林、重度采伐林和油棕种植园收集凋落物混合物和土壤，并在受控环境条件下进行全杂交、因子微观试验。研究发现，虽然凋落物质量是凋落物质量损失的最重要预测因子，但土壤来源对凋落物质量损失的影响也很显著，对总变异的贡献率在5.17% ~ 15.43%之间。与原生林和油棕人工林相比，原生林微生物分解器群落的功能广度更大，所有凋落物类型在与原生林土壤结合时分解速度更快。来自中度采伐森林的化学性质最顽固的凋落物（氮含量最低，木质素、木质素：氮和碳氮比最高）在与其“家乡”土壤结合时分解得更快（主场优势），而来自油棕的最不稳定的凋落物在与其“家乡”土壤结合时分解得最慢。这与较低的土壤微生物总量有关。综上所述，这些发现表明，虽然凋落物质量调节了凋落物分解率，但土壤微生物分解者群落在不同土地利用方式之间存在功能差异，并解释了很大比例的变化。在评估对分解等关键生态系统过程的影响时，应考虑扰动对土壤的影响，包括微生物群落结构，以及植物群落的变化。
Industrial logging and agricultural expansion are driving rapid transformations of tropical ecosystems, modifying patterns in above-ground plant and below-ground microbial communities. However, the extent to which these changes in biodiversity drive modifications of ecosystem process rates such as leaf litter decomposition is poorly understood. To determine the relative effects of changes to the chemical quality of litter and shifts in microbial decomposers on leaf litter decomposition rates, we performed a controlled, reciprocal transplant, litter decomposition experiment across a tropical land-use disturbance gradient. Litter mixtures and soils were collected from old growth forest, moderately logged forest, heavily logged forest, and oil palm plantation in Sabah, Malaysia, and combined in a fully crossed, factorial microcosm experiment maintained under controlled environmental conditions. We found that whilst litter quality was the most important predictor of litter mass loss, soil origin was also significant, explaining between 5.17 and 15.43% of total variation. Microbial decomposer communities from old growth forest had greater functional breadth relative to those from logged forests and oil palm plantation as all litter types decomposed faster when combined with old growth soil. The most chemically recalcitrant litter (lowest N, highest lignin, lignin:N, and C:N ratio) from moderate logged forest decomposed faster when combined with its "home" soil (Home-Field Advantage) whilst the most labile litter from oil palm decomposed slowest when combined with its "home" soil. This was correlated with lower total soil microbial biomass. Taken together, these findings demonstrate that whilst litter quality regulated rates of litter decomposition across the disturbance gradient, soil microbial decomposer communities were functionally dissimilar between land uses and explained a significant proportion of variation. The impact of disturbance on soil, including microbial community structure, should be considered alongside changes to plant communities when assessing effects on crucial ecosystem processes such as decomposition.