Human activities have radically shaped the global landscape, affecting the structure and function of ecosystems. Habitat loss is one of the most visible changes to the landscape and a primary driver of species declines; however, anthropogenic environmental contamination also threatens population persistence, but is not as readily observed. Aquatic organisms are especially susceptible to chemical perturbations, which can negatively impact survival and fitness related traits. Some populations have evolved tolerance to chemical stressors, which could mitigate the consequences associated with contamination. Amphibians are experiencing global declines due to multiple stressors and are particularly at risk to aquatic chemical stressors due to their permeable skin and reliance on wetlands for reproduction and larval development. However, amphibians also have substantial plasticity in response to environmental variation. We designed our study to examine whether tolerance to heavy metals is greater in Southern toad (Anaxyrus terrestris) larvae from wetlands with a history of contamination. Considering many of the most common trace elements elicit acute toxicity by disrupting osmotic- and ionic-regulation, we hypothesized that alterations to these aspects of physiology resulting from multigenerational exposure to trace element mixtures would be the most likely routes by which tolerance would evolve. We used copper (Cu) as a proxy for heavy metal exposure because it is a widely distributed aquatic stressor known to cause osmotic stress that can also cause mortality at levels commonly encountered in the environment. We found considerable within and among population variation in Cu tolerance, as measured by time to death. Larvae from populations living in sites contaminated with mixtures of heavy metals associated with coal fly ash were no more tolerant to Cu than those from reference sites. However, larvae from a population inhabiting a constructed wetland complex with high Cu levels were significantly more tolerant; having half the risk of mortality as reference animals. This wetland complex was created < 20 years ago, thus if elevated Cu tolerance in this population is due to selection in the aquatic habitat, such adaptation may occur rapidly (i.e. ∼10 generation). Our results provide evidence that amphibians may be able to evolve tolerance in response to trace element contamination, though such tolerance may be specific to the combination of contaminants present.

人类活动从根本上改变了全球格局，影响了生态系统的结构和功能。栖息地的丧失是景观最明显的变化之一，也是物种减少的主要驱动力。然而，人为的环境污染也威胁着人口的持久性，但还不那么容易观察到。水生生物特别容易受到化学扰动的影响，这会对生存和健身相关性状产生负面影响。一些人群已经对化学应激源产生了耐受性，这可以减轻与污染有关的后果。由于多种压力源，两栖动物正在全球范围内下降，由于其渗透性强的皮肤以及对湿地繁殖和幼体发育的依赖，两栖动物尤其面临水生化学胁迫的风险。然而，对于环境变化，两栖动物也具有相当大的可塑性。我们设计了这项研究，以检验南部蟾蜍对重金属的耐受性是否更高（rest藜）具有污染史的湿地​​幼虫。考虑到许多最常见的微量元素会通过破坏渗透和离子调节而引起急性毒性，因此我们假设，多代暴露于微量元素混合物导致的生理学这些方面的改变将是耐受性发展的最可能途径。我们使用铜（Cu）作为重金属暴露的替代物，因为它是一种分布广泛的水生应激源，已知会引起渗透压，也可能导致环境中常见水平的死亡率。我们发现，通过死亡时间来衡量，在人群内和人群中对铜的耐受性差异很大。生活在被粉煤灰重金属混合物污染的地点的种群中的幼虫对铜的耐受性不比参考地点的耐受。然而，居住在人工建造的湿地复合体中且铜含量高的种群中的幼虫具有更强的耐受性。作为参考动物，死亡风险只有一半。这种湿地复合体是在20年前创建的，因此，如果该种群对铜的耐受性提高是由于在水生生境中的选择，那么这种适应可能会迅速发生（即约10代）。我们的结果提供了证据，表明两栖动物可能对痕量元素的污染产生耐受性，尽管这种耐受性可能是存在的污染物的组合所特有的。来自居住在高Cu水平的人工湿地的种群中的幼虫具有更强的耐受性；作为参考动物，死亡风险只有一半。这种湿地复合体是在20年前创建的，因此，如果该种群对铜的耐受性提高是由于在水生生境中的选择，那么这种适应可能会迅速发生（即约10代）。我们的结果提供了证据，表明两栖动物可能对痕量元素的污染产生耐受性，尽管这种耐受性可能是存在的污染物的组合所特有的。居住在高Cu含量的人工湿地的种群中的幼虫具有更高的耐受性；作为参考动物，死亡风险只有一半。这种湿地复合体是在20年前创建的，因此，如果该种群对铜的耐受性提高是由于在水生生境中的选择，那么这种适应可能会迅速发生（即约10代）。我们的结果提供了证据，表明两栖动物可能对痕量元素的污染产生耐受性，尽管这种耐受性可能是存在的污染物的组合所特有的。这种适应可能很快发生（即约10代）。我们的结果提供了证据，表明两栖动物可能对痕量元素的污染产生耐受性，尽管这种耐受性可能是存在的污染物的组合所特有的。这种适应可能很快发生（即约10代）。我们的结果提供了证据，表明两栖动物可能对痕量元素的污染产生耐受性，尽管这种耐受性可能是存在的污染物的组合所特有的。