Study quantifies animal deaths in mega-fire in the Pantanal in 2020

Gathered together in the Wildlife Studies Group (GEVS), researchers from various institutions published, at late September, an article in the British Ecological Society which points out that extreme environmental fires, such as those in the Pantanal in 2020, are likely to become increasingly common, driven by climate change. Carried out in collaboration with Sesc Pantanal employees who have been working in the area for more than 20 years, the study is led by José Luis Cordeiro, a researcher at Fiocruz Ceará, and Luiz Flamarion Barbosa de Oliveira, a professor at the National Museum of the Federal University of Rio de Janeiro (UFRJ), who are working on participatory environmental monitoring. The article, entitled Modelagem espacial e estimativa da mortalidade de mamíferos pelos mega incêndios do Pantanal em 2020 [Spatial modelling and estimation of mammals' mortalities by Pantanal 2020 megafires], is primarily signed by Ismael Brack, a researcher at the Federal University of Rio Grande do Sul (UFRGS).

The data show that, of the nine mammal species most impacted, three are considered endangered (photo: Marcelo Camargo/Agência Brasil)

"The data shows that 26 of the 27 species of medium and large mammals found in the region died directly as a result of the fires, with an average estimate of around 49,000 individuals," says Cordeiro, one of the article's organizers. The Fiocruz Ceará researcher believes that assessing the impacts of this type of extreme event on wild animals is important for conservation planning and can provide valuable information on how these impacts relate to the landscape.

The researcher explains that carcass sampling with a double observer protocol was used to estimate the numbers and assess the spatial patterns of direct mortality of medium and large mammals in a 1,080 km2 reserve in northern Pantanal, the Sesc Pantanal RPPN. Among the species most affected are capuchin monkeys, agoutis, collared peccaries, tapirs, roe deer, giant anteaters, coatis and capybaras.

The data also shows that of the nine mammal species most impacted, three are considered endangered (capuchin monkeys, collared peccaries and tapirs). If information on the density and size of populations in the Pantanal is taken into account, tapirs, anteaters and agoutis would be the species most affected.

According to the authors, the direct mortality of mammals by fire was influenced by aspects of the landscape related to their habitat, by characteristics of the species probably related to escape or refuge strategies and by the intensity of the fires. "Mortalities showed a generally positive relationship with non-flooded forests (a fire-sensitive habitat in the Pantanal) and with the severity of fires," the article points out. Ponds, small artificial lakes, a common structure in the Pantanal landscape, had 7.5 times more deaths than in other areas.

As to the study, the Fiocruz Ceará researcher says that it was possible to identify critical areas of mortality concentration associated with aspects of the landscape; to identify the species most affected and to assess the average ratios for the entire group of medium and large mammals. "We discussed management and conservation actions in two contexts: prioritization of species for rescue and monitoring; and territorial prioritization for fighting and preventing fires," he adds. "As far as we know, this study is the first attempt to model and identify the factors that influence locations with higher or lower animal mortalities as a direct result of environmental fires based on carcass counts."

The article points out the influence of species' behavior and the characteristics of environmental fires, such as their intensity, on the occurrence and number of deaths by fire. "We estimate that tens of thousands (49,000 individuals) of medium and large mammals of 26 different species have died due to these catastrophic fires in the Sesc Pantanal Reserve, which burned more than 90% of its area in 2020. If we consider subsequent deaths due to hunger, thirst, infections, lung diseases and exposure to predators, the total mortality estimates could be much higher," he says.

According to the study, the research could help prevent fires in key areas. "The impacts of fire can be minimized by reducing its speed and severity with direct firefighting or prescribed burning in buffer zones, preventing the flames from reaching these areas. Forest habitats, particularly in non-flooded areas, need special attention as they are fire-sensitive vegetation and a crucial source of food (fruit and seeds) for several species," Cordeiro argues.

Post-fire actions can prioritize the implementation of emergency actions, providing food, water and shelter in key locations and promoting the restoration of fire-sensitive vegetation (e.g. forests). Finally, these most affected species should be prioritized in monitoring plans to assess their recovery and future population trends.