In the catchment of the River Segura (SE Spain), ongoing Eurasian otter (Lutra lutra) recovery and concurrent spread of human settlements are resulting in increasing otter records into urban areas. We analysed otter diet along a natural-to-urban gradient, with the main aim of assessing to which extent man-driven variation in food availability affects its feeding habits and how this secretive mustelid can thrive in apparently unsuitable habitats. From 2016 to 2019, we collected 521 spraints, monitoring 37 sampling stations (mean length ± SD = 0.5 ± 0.3 km). In natural areas, the percent cover of undisturbed banks was the highest, with the lowest number of water abstraction systems, whilst water pollution was the highest in urban areas. Introduced red swamp crayfish (Procambarus clarkii) and fish formed the bulk of otter diet. The two most preyed fish, Luciobarbus sclateri and Pseudochondrostoma polylepis, were among the most abundant species in the river, confirming the generalist feeding behaviour of the otter. The contribution of non-native fish was on average low, while invasive crayfish exceeded the overall importance of fish in all habitats except urban areas. Overall, diet data did not allow attesting food as a limiting resource for otters in urban areas. In contrast, marking intensity varied consistently with the natural-to-urban gradient (from 0.31 to 0.65 spraints/100 m in urban- and natural areas, respectively), suggesting that human disturbance (i.e. habitat modification and water pollution) may play a major role in shaping otter distribution.

在塞古拉河（西班牙东南部）的流域，欧亚水獭（Lutra lutra）的恢复和人类住区的同时传播正在导致水獭在城市地区的记录增加。我们按照自然-城市梯度对水獭饮食进行了分析，其主要目的是评估人为驱动的食物可获得性变化在多大程度上影响其摄食习惯，以及这种分泌性芥菜素如何在显然不合适的栖息地中繁衍生息。从2016年到2019年，我们收集了521个扭伤，监测了37个采样站（平均长度±SD = 0.5±0.3 km）。在自然地区，未受干扰的银行的覆盖率最高，取水系统的数量最少，而城市地区的水污染最高。引入红色沼泽小龙虾（Procambarus clarkii）和鱼形成了大部分的水獭饮食。两种最被捕食的鱼类，Luciobarbus sclateri和Pseudochondrostoma polylepis，是河中物种最丰富的鱼类，这证实了水獭的全食性。非本地鱼类的贡献平均较低，而侵入性小龙虾超出了除城市地区以外所有生境中鱼类的总体重要性。总体而言，饮食数据不允许将食物作为城市地区水獭的限制资源。相反，标记强度随自然-城市梯度变化而变化（在城市和自然区域，扭伤强度从0.31到0.65扭伤/ 100 m），这表明人为干扰（例如，栖息地的改变和水污染）可能起主要作用。在塑造水獭分布中的作用。