Distance sampling surveys reveal 17 million vertebrates directly killed by the 2020’s wildfires in the Pantanal, Brazil

Abstract

Anthropogenic factors have significantly influenced the frequency, duration, and intensity of meteorological drought in many regions of the globe, and the increased frequency of wildfires is among the most visible consequences of human-induced climate change. Despite the fire role in determining biodiversity outcomes in different ecosystems, wildfires can cause negative impacts on wildlife. We conducted ground surveys along line transects to estimate the first-order impact of the 2020 wildfires on vertebrates in the Pantanal wetland, Brazil. We adopted the distance sampling technique to estimate the densities and the number of dead vertebrates in the 39,030 square kilometers affected by fire. Our estimates indicate that at least 16.952 million vertebrates were killed immediately by the fires in the Pantanal, demonstrating the impact of such an event in wet savanna ecosystems. The Pantanal case also reminds us that the cumulative impact of widespread burning would be catastrophic, as fire recurrence may lead to the impoverishment of ecosystems and the disruption of their functioning. To overcome this unsustainable scenario, it is necessary to establish proper biomass fuel management to avoid cumulative impacts caused by fire over biodiversity and ecosystem services.

Assessing the role of compound drought and heatwave events on unprecedented 2020 wildfires in the Pantanal

“…More than 3.9 million hectares were burned, an area four times larger than the longterm average observed between 2001 and 2019 [3,4]. The Pantanal 2020 fire (hereafter P20F) season may have directly affected 17 million native vertebrates [5] and resulted in total national economic losses of ∼USD 3.6 billion [6].…”

A compound event-oriented framework to tropical fire risk assessment in a changing climate

“…It consists of a very complex and diverse ecosystem, sharing borders with the Amazonia, Cerrado and Chaco biomes and housing seven native indigenous populations (figures 1(e) and S1). The Pantanal's burned area between 1985 and 2020 exceeded all the other Brazilian biomes [37], and during the anomalous dry and warm year of 2020, nearly 30% of the Biome was burned, affecting at least 65 million vertebrates [38], directly killing 17 million of them [19]. In 2020, the fire season across the Pantanal has reached striking records of fire activity, with an increase of about six times the annual cumulative number of fires in relation to the 2012-2019 average [15][16][17].…”

“…Located in the ecotone between the Amazonia and Cerrado biomes, the Xingu region is hypothesized to become vulnerable to transitions from forest into drier environment with more sparse vegetation, and an intensification of the region's fire regimes due to climate change may already be underway [14]. In the same manner, the Pantanal has been increasingly degraded by fires [15,16] and abrupt changes in its fire regimes could drive large-scale vegetation degradation, with catastrophic consequences for biodiversity [15,[17][18][19]. In combination with the lack of sustainable environmental and conservation practices, climate change might exacerbate the decreasing resilience during extremely dry and warm years, resulting in many negative social and environmental consequences across these biocultural heritage sites.…”

Discovery of underground shelters occupied by the Chacoan Marsh Rat after massive wildfires in Pantanal, Brazil

“…In some anomalous years, the fires in Pantanal may cover larger areas, influenced by natural events associated with anthropogenic factors such as the opening of pastures and agricultural areas (Alho and Silva 2012; Garcia et al 2021;Marengo et al 2021;Marques et al 2021). This was the case in 2020, when wildfires burned approximately 26 % of the Brazilian Pantanal (Garcia et al 2021;Libonati et al 2021) and directly affected local flora and fauna (Garcia et al 2021;Tomas et al 2021).…”

“…4.4 -5.0 million mammals died directly by these wildfires, ca. 3.6 -3.8 were rodents (Tomas et al 2021).…”