Jochum Malte, Barnes Andrew D, Weigelt Patrick, Ott David, Rembold Katja, Farajallah Achmad, Brose Ulrich
J. F. Blumenbach Institute for Zoology & Anthropology, University of Goettingen, Goettingen, Germany.
German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany.
J Anim Ecol. 2017 Sep;86(5):1114-1123. doi: 10.1111/1365-2656.12695. Epub 2017 Jun 19.
High biodiversity and biomass of soil communities are crucial for litter decomposition in terrestrial ecosystems such as tropical forests. However, the leaf litter that these communities consume is of particularly poor quality as indicated by elemental stoichiometry. The impact of resource quantity, quality and other habitat parameters on species richness and biomass of consumer communities is often studied in isolation, although much can be learned from simultaneously studying both community characteristics. Using a dataset of 780 macro-invertebrate consumer species across 32 sites in tropical lowland rain forest and agricultural systems on Sumatra, Indonesia, we investigated the effects of basal resource stoichiometry (C:X ratios of N, P, K, Ca, Mg, Na, S in local leaf litter), litter mass (basal resource quantity and habitat space), plant species richness (surrogate for litter habitat heterogeneity), and soil pH (acidity) on consumer species richness and biomass across different consumer groups (i.e. 3 feeding guilds and 10 selected taxonomic groups). In order to distinguish the most important predictors of consumer species richness and biomass, we applied a standardised model averaging approach investigating the effects of basal resource stoichiometry, litter mass, plant species richness and soil pH on both consumer community characteristics. This standardised approach enabled us to identify differences and similarities in the magnitude and importance of such effects on consumer species richness and biomass. Across consumer groups, we found litter mass to be the most important predictor of both species richness and biomass. Resource stoichiometry had a more pronounced impact on consumer species richness than on their biomass. As expected, taxonomic groups differed in which resource and habitat parameters (basal resource stoichiometry, litter mass, plant species richness and pH) were most important for modulating their community characteristics. The importance of litter mass for both species richness and biomass indicates that these tropical consumers strongly depend on habitat space and resource availability. Our study supports previous theoretical work indicating that consumer species richness is jointly influenced by resource availability and the balanced supply of multiple chemical elements in their resources.
土壤群落的高生物多样性和生物量对于热带森林等陆地生态系统中的凋落物分解至关重要。然而，从元素化学计量学来看，这些群落所消耗的落叶质量特别差。资源数量、质量和其他栖息地参数对消费者群落物种丰富度和生物量的影响通常是单独研究的，尽管同时研究这两个群落特征可以学到很多东西。利用印度尼西亚苏门答腊岛热带低地雨林和农业系统中32个地点的780种大型无脊椎动物消费者物种的数据集，我们研究了基础资源化学计量（当地落叶中氮、磷、钾、钙、镁、钠、硫的碳：X比率）、凋落物质量（基础资源数量和栖息地空间）、植物物种丰富度（凋落物栖息地异质性的替代指标）和土壤pH值（酸度）对不同消费者群体（即3个取食类群和10个选定分类群）消费者物种丰富度和生物量的影响。为了区分消费者物种丰富度和生物量的最重要预测因子，我们应用了一种标准化模型平均方法，研究基础资源化学计量、凋落物质量、植物物种丰富度和土壤pH值对消费者群落特征的影响。这种标准化方法使我们能够确定这些影响在消费者物种丰富度和生物量方面的大小和重要性的差异和相似之处。在所有消费者群体中，我们发现凋落物质量是物种丰富度和生物量的最重要预测因子。资源化学计量对消费者物种丰富度的影响比对其生物量的影响更为显著。正如预期的那样，分类群在哪些资源和栖息地参数（基础资源化学计量、凋落物质量、植物物种丰富度和pH值）对调节其群落特征最为重要方面存在差异。凋落物质量对物种丰富度和生物量都很重要，这表明这些热带消费者强烈依赖栖息地空间和资源可用性。我们的研究支持了先前的理论工作，表明消费者物种丰富度受到资源可用性及其资源中多种化学元素平衡供应的共同影响。
