The Pampean region has become one of the most urbanised areas in South America with more than 91% of the Argentinean population. This region is ideal for human settlements that have historically chosen riverine grassland areas to settle. Consequently, urban streams are increasingly subjected to pressures affecting their functioning. The aim of this study was to assess urbanisation effects on two proxies of stream integrity: leaf litter decay and benthic invertebrate assemblage colonizing litter in streams draining urbanised versus reference grassland areas. We placed plastic coarse‐ and fine‐mesh bags containing Populus nigra leaf litter along three urban and three reference reaches, and these were retrieved periodically to determine the remaining leaf mass and the identity and quantity of detritivore assemblage colonizing bags. The decay rate was negatively affected by urbanisation, and it followed a negative relationship with increasing Nitrogen concentration (mostly ammonia) and a hump‐shape relationship against soluble reactive phosphorus. Urban invertebrate assemblages were significantly different from the reference reaches, and were species‐poorer and characterized by tolerant taxa belonging to Naididae, Glossiphoniidae, and Nematoda, whereas Hyalellidae, Aeglidae, Chironomidae, Caenidae, Baetidae, and Hydrobiidae represented the reference reaches. Our proxies of structural (i.e., invertebrate assemblages) and functional (i.e., leaf litter breakdown) stream integrity were mostly driven by a nutrient‐enrichment gradient and responded in a similar direction but with different magnitude to urban alterations.

中文翻译：

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城市化进程降低了凋落物分解率，并影响了潘邦溪流的底栖无脊椎动物结构

潘庞地区已成为南美城市化程度最高的地区之一，阿根廷人口超过91％。该地区是人类定居的理想之地，这些人类定居历来都选择沿河草原地区定居。因此，城市溪流日益承受影响其功能的压力。这项研究的目的是评估城市化对河流完整性的两个代理的影响：叶枯萎和底栖无脊椎动物组合定居在排水的城市化与参考草地地区的河流中。我们放置了装有黑杨的塑料粗网袋和细网袋沿三个市区和三个参考河段的凋落物，定期对其进行检索，以确定剩余的叶子质量以及有害生物组合定植袋的种类和数量。衰减速率受到城市化的负面影响，并且与氮浓度（主要是氨）的增加呈负相关，并且与可溶性活性磷呈驼峰形关系。城市无脊椎动物组合与参考范围显着不同，且物种较贫乏，其特征是耐科类群属于鹦鹉螺科，伞形科和线虫科，而鬣蜥科，A科，线虫科、,科，Ba科和水生科则是参考科。我们在结构（即无脊椎动物组合）和功能（即