Several constituents of the current global change are usually deemed accountable for the worldwide declines of amphibian populations. Among these, water contamination poses a major threat, especially to larval stages, which are unable to escape a polluted water body. This problem is remarkable in agrosystems, one of the main sources of water pollution and whose area is forecasted to increase in the forthcoming decades. However, pollutants represent a selective pressure that may result in tolerance in affected areas. In this work, we tested whether chronic exposure to a sublethal concentration of ammonium (10 mg/L), one of the most frequent agrochemicals, affects differently hatching success, survivorship, morphology and swimming performance of Pelophylax perezi tadpoles from agrosystem and pine grove habitats. Ammonium diminished survivorship at the earliest stages after hatching. Thus, lower density was a by-product of exposure to ammonium. Higher density slowed down development, reduced snout-vent length, and had a sharper negative effect on body mass and tail length and depth of ammonium treated individuals with respect to the control. In turn, ammonium accelerated development and increased body mass, SVL, and tail length and depth. These effects did not depend on provenance habitat. However, only pine grove tadpoles’ swimming speed was negatively affected by ammonium, which supports the hypothesis that agrosystem tadpoles are more tolerant to ammonium. Finally, corroborating previous findings, tadpoles with larger bodies and tails were faster swimmers, whereas proportionally more massive individuals were slower, and tail depth was unrelated to swimming speed.

当前全球变化的几个组成部分通常被认为是全球两栖动物数量下降的原因。其中，水污染构成了主要威胁，特别是对无法逃离受污染水体的幼虫阶段。这个问题在农业系统中尤为突出，农业系统是水污染的主要来源之一，预计未来几十年其面积会增加。然而，污染物代表了一种选择压力，可能导致受影响地区的耐受性。在这项工作中，我们测试了长期暴露于亚致死浓度的铵 (10 mg/L)（最常见的农用化学品之一）是否会影响Pelophylax perezi 的孵化成功率、存活率、形态和游泳性能来自农业系统和松树林栖息地的蝌蚪。在孵化后的最早阶段，铵会降低存活率。因此，较低的密度是暴露于铵的副产品。与对照组相比，较高的密度减缓了发育速度，减少了口鼻部的长度，并且对接受铵处理的个体的体重、尾巴长度和深度有更明显的负面影响。反过来，铵盐会加速发育并增加体重、SVL 以及尾巴长度和深度。这些影响并不取决于原产地栖息地。然而，只有松树林蝌蚪的游泳速度受到铵的负面影响，这支持了农业系统蝌蚪对铵更耐受的假设。最后，证实了之前的发现，身体和尾巴较大的蝌蚪游泳速度更快，