Židišinová Emília, Novikmec Milan, Svitok Marek
Department of Biology and General Ecology, Faculty of Ecology and Environmental Sciences, Technical University in Zvolen, Zvolen, Slovakia.
Department of Forest Ecology, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences Prague, Prague, Czech Republic.
PLoS One. 2025 Aug 14;20(8):e0327999. doi: 10.1371/journal.pone.0327999. eCollection 2025.
Many freshwater ecosystems rely on the decomposition of organic matter as a key process for nutrient cycling and energy flow. Small lentic freshwater ecosystems, such as ponds, often derive a large amount of energy from allochthonous detritus due to their close connection with the terrestrial environment. However, the process of leaf litter decomposition in ponds remains poorly understood. We conducted a microcosm experiment in a pond environment to investigate intra- and inter-specific variation in organic matter processing by three shredders (Tipula sp., Sericostoma sp. and Gammarus fossarum) and to assess the effects of shredder community characteristics on the mass loss of black alder (Alnus glutinosa) leaf litter. We developed a novel approach to quantify functional traits directly related to litter processing. Detailed gut content analysis revealed significant inter- and intra-specific variation in the organic matter particles ingested by individual shredder taxa. Our results showed that neither taxonomic nor functional diversity reliably predicts leaf litter decomposition rates in ponds. Instead, the keystone shredder Sericostoma showed a pronounced effect on decomposition rates driven by their unique feeding behaviour and density-dependent shifts in particle size preferences. These findings highlight the importance of a detailed understanding of species-specific functional traits and behaviour in shaping ecosystem processes, as the role of keystone species can outweigh the contributions of overall diversity measures in driving ecosystem processes.
许多淡水生态系统依赖有机物分解作为养分循环和能量流动的关键过程。小型静水淡水生态系统，如池塘，由于与陆地环境紧密相连，常常从异地碎屑中获取大量能量。然而，池塘中落叶分解的过程仍知之甚少。我们在池塘环境中进行了一项微观实验，以研究三种碎食者（大蚊属、丝角石蛾属和河蚋）在有机物处理方面的种内和种间差异，并评估碎食者群落特征对黑桤木（Alnus glutinosa）落叶质量损失的影响。我们开发了一种新方法来直接量化与落叶处理直接相关的功能性状。详细的肠道内容物分析揭示了各个碎食者类群摄入的有机物质颗粒存在显著的种间和种内差异。我们的结果表明，分类多样性和功能多样性都不能可靠地预测池塘中落叶的分解速率。相反，关键碎食者丝角石蛾通过其独特的摄食行为和粒径偏好的密度依赖性变化，对分解速率产生了显著影响。这些发现凸显了详细了解物种特异性功能性状和行为对塑造生态系统过程的重要性，因为关键物种在驱动生态系统过程中的作用可能超过整体多样性指标的贡献。
