Erika M. Santana, Luis Cesar Schiesari, Fernando Ribeiro Gomes, Marcio Roberto Costa Martins

Industrial pollution is a significant global threat to biodiversity, but its consequences on rainforest ecosystems remains poorly understood. Amphibians are especially susceptible to pollutants released on natural environments due to their aquatic-terrestrial life cycle. Here, we explored the effects of severe historical air, water and soil industrial pollution of Cubatão Industrial Complex (São Paulo state, Brazil) on the physiological condition of Rhinella ornate individuals, an endemic toad species of Atlantic Forest, a world biodiversity hotspot. We hypothesized that individuals sampled at localities closer to the pollution source will present worse indicators of physiological health. As predicted, toads at decreasing distances from the pollution source presented enlargement of organs related with detoxification function (liver and kidneys) and with compensatory immunological function (spleen). Contrary to our predictions, however, we found only a weak negative effect of proximity to the pollution source on individuals’ body condition index, and no effects on fertility (testicles masses) or macroparasite infection (eosinophil counts). Surprisingly, proximity to the pollution source was associated with lower chronical stress levels (neutrophil/lymphocyte ratio) on individuals. We discuss which physiological process could promote the alterations found on the toads. We also discuss the possible evolution of a local resistance to contamination on toads from populations closer from pollution source, giving the more than 60 years of exposure to chemical contaminants in the area.