Effects of Amazonian flying rivers on frog biodiversity and populations in the Atlantic rainforest

Brazil's Amazon Oxygen Crisis: How Lives and Health Were Sacrificed During the Peak of COVID-19 to Promote an Agenda with Long-Term Consequences for the Environment, Indigenous Peoples, and Health

In January 2021, oxygen supplies in the Amazon region's largest city were allowed to run out at the peak of the second wave of the COVID-19 epidemic, shocking the world as hospital patients expired for lack of this basic medical resource in Manaus, which during the first COVID-19 wave had become the world's first city to bury its dead in mass graves. Brazil's authorities used this tragedy to further a political agenda that implies enormous environmental and human-rights consequences. Transport of oxygen was used to promote building a road that, together with its planned side roads, would give deforesters access to much of what remains of Brazil's Amazon Forest. Here, we demonstrate that the logistical strategy adopted by the Jair Bolsonaro administration's Ministries of Health and Infrastructure to bring oxygen to Manaus was the worst possible choice, and the foreseeable delay in the arrival of oxygen cost hundreds of lives. Rather than sending trucks to carry oxygen on the nearly impassible Highway BR-319 during the rainy season, the most appropriate transport option was barges on the Madeira River. As oxygen supplies dwindled in Manaus, the families of wealthier COVID-19 victims scrambled to buy the few remaining cylinders at prices out of reach for those in poorer (and often ethnically distinct) economic strata. Ethnic health disparities are aggravated by both the direct consequences of the oxygen crisis and, on the longer term, by the consequences of the highway project that political use of the crisis materially advanced.

Skin microbiome disturbance linked to drought-associated amphibian disease

The onset of global climate change has led to abnormal rainfall patterns, disrupting associations between wildlife and their symbiotic microorganisms. We monitored a population of pumpkin toadlets and their skin bacteria in the Brazilian Atlantic Forest during a drought. Given the recognized ability of some amphibian skin bacteria to inhibit the widespread fungal pathogen Batrachochytrium dendrobatidis (Bd), we investigated links between skin microbiome health, susceptibility to Bd and host mortality during a die-off event. We found that rainfall deficit was an indirect predictor of Bd loads through microbiome disruption, while its direct effect on Bd was weak. The microbiome was characterized by fewer putative Bd-inhibitory bacteria following the drought, which points to a one-month lagged effect of drought on the microbiome that may have increased toadlet susceptibility to Bd. Our study underscores the capacity of rainfall variability to disturb complex host-microbiome interactions and alter wildlife disease dynamics.

Climate change in the Central Amazon and its impacts on frog populations

Frog population declines have already been observed in the central Amazon even for common species that are considered not to be in danger of extinction. The Amazon is close to its limit of tolerated deforestation, and parts of the forest have already been modified by climate change, which raises questions about how the fauna in these areas would adapt to climate changes by the middle and the end of this century. In this study we used population density data on seven species of Amazonian frogs and analyzed the relationship between the activity of these species and temperature, precipitation, and relative humidity. We also used the least-squares method with logarithmic models to assess whether climate change projected by the Intergovernmental Panel on Climate Change (IPCC) would be an indicator of the population dynamics of these species. Our results suggest that even common species may be may experience population declines and extinction in the next decades due to climate changes.