The decomposition of plant litter is a fundamental ecological process in small forest streams. Litter decomposition is mostly controlled by litter characteristics and environmental conditions, with shredders playing a critical role. The aim of this study was to evaluate the effect of leaf species (Maprounea guianensis and Inga laurina, which have contrasting physical and chemical characteristics) and water nutrient enrichment (three levels) on leaf litter chemical characteristics and fungal biomass, and subsequent litter preference and consumption by Phylloicus sp. (a typical shredder in tropical streams). Maprounea guianensis leaves had lower lignin and nitrogen (N) concentrations, higher polyphenols concentration and lower lignin:N ratio than I. laurina leaves. Phosphorus concentrations were higher for both leaf species incubated at the highest water nutrient level. Fungal biomass was higher on M. guianensis than on I. laurina leaves, but it did not differ among nutrient levels. Relative consumption rates were higher when shredders fed on M. guianensis than on I. laurina leaves, due to the lower lignin:N ratio and higher fungal biomass of M. guianensis. Consumption rates on M. guianensis leaves were higher for those exposed to low water nutrient levels than for those exposed to moderate water nutrient levels. Feeding preferences by shredders were not affected by leaf species or nutrient level. The low carbon quality on I. laurina leaves makes it a less attractive substrate for microbial decomposers and a less palatable resource for shredders. Changes in litter input characteristics may be more important than short-term nutrient enrichment of stream water on shredder performance and ecosystem functioning.

植物凋落物的分解是小森林溪流中的基本生态过程。垃圾的分解主要由垃圾的特性和环境条件控制，而碎纸机起着至关重要的作用。这项研究的目的是评估叶片物种（Maprounea guianensis和Inga laurina，具有相反的物理和化学特性）和水分营养富集（三个水平）对叶片凋落物化学特性和真菌生物量的影响，以及随后的凋落物偏好和Phylloicus sp。的消费。（热带溪流中的典型碎纸机）。桂麻与月桂叶相比，叶片的木质素和氮（N）浓度较低，多酚浓度较高，木质素：N比例较低。在最高水养分水平下孵育的两种叶片的磷浓度都较高。M. guianensis上的真菌生物量高于月桂I.叶片，但营养水平之间没有差异。当送入粉碎机上相对消费率较高M.花草比I.牛奶树的信噪比和更高的真菌类生物质：叶，由于较低的木质素M.花草。圭亚那花的消费率暴露于低水养分水平的叶片比暴露于中等水养分水平的叶片高。切碎机的进食偏好不受叶片种类或营养水平的影响。月桂I.叶片的低碳质量使其成为微生物分解剂的吸引力较差的基质，而粉碎机的味蕾也较差。垃圾输入特性的变化可能比溪水的短期养分富集对切碎机性能和生态系统功能更重要。