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

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.

Molecular detection of hemogregarines and haemosporidians in Brazilian free-living testudines.

Morphological and molecular techniques were used to investigate the presence of hemogregarines and haemosporidians in biological samples of free-living Geoffroy's side-necked turtles (Phrynops geoffroanus) and Giant Amazon turtles (Podocnemis expansa) from Brazil. No evolutionary form of haemosporidians or hemogregarines were observed in the blood smears of 83 P. geoffroanus samples, and there were no meronts in the histological sections of 31 necropsied P. geoffroanus samples. All DNA samples extracted from P. geoffroanus tissues and blood aliquots were negative in haemosporidian PCR assays (based on the mitochondrial cytochrome b gene) and hemogregarine PCR assays (based on the 18S rRNA gene). In the analysis of blood smears of all seven Podocnemis expansa evaluated, gametocytes of hemogregarines were observed. The seven P. expansa were negative in the haemosporidian PCR assays. Moreover, hemogregarine DNA was detected in blood samples from all of the sampled P. expansa. The phylogenetic maximum likelihood inference and probabilistic Bayesian inference revealed five closely related genotypes that formed a monophyletic group. There was also a sister group to the lineage that consisted of Haemogregarina spp. of freshwater turtles from Canada, Italy, Mozambique, Kenya, Gabon, Vietnam, and China. The findings suggest that free-living P. expansa were parasitized by a new genotype or even a possible new species of the genus Haemogregarina. Haemosporidians and hemogregarines are not frequently found in P. geoffroanus in the studied region under the local conditions of that period.