A Double Threat to Amazonian Amphibian Larvae: A Review of Toxic Contaminants and Their Interaction with Global Climate Change

Amazonia holds global significance due to its essential role in climate regulation and its high biological diversity. However, in recent decades, the region has faced serious threats to its forest structure and rich biodiversity. Human activities, including habitat alterations, pollution, introduction of invasive species, pathogens, and accelerated climate change, have been identified as primary factors contributing to the decline of various populations in these environments. Approximately 76% of amphibian species are estimated to occur in tropical forests, highlighting their significance and the potential for discovering new species. Conversely, knowledge about the effects of environmental contamination in the region remains scarce, which is particularly concerning given the current scenario of climate change. Contaminants such as pesticides and microplastics can induce a range of morphological, physiological, and behavioral alterations in frogs and toads, especially during larval stages. When coupled with climate change, where rising temperatures play a pivotal role, these factors pose intricate challenges for amphibians, intensifying adverse effects and contributing to population declines. Here, we provide a review of the impacts of environmental pollution on various aspects of anuran amphibians, providing insight into the current state of knowledge regarding Amazonia and highlighting knowledge gaps. Major categories of negative effects resulting from aquatic contamination in amphibians, with a particular focus on how climate change interacts with contaminants, amplifying their deleterious effects.