Marcelo Magioli

Disruptions in fire regimes increasingly threaten biodiversity worldwide, yet the long‐term impacts of megafires on mammal assemblages in fire‐prone ecosystems remain poorly understood. The 2020 megafires in the Brazilian Pantanal, the world's largest tropical wetland, burned one‐third of its area, causing unprecedented biodiversity impacts and highlighting the need to understand ecological consequences. We assessed the effects of the 2020 megafires on mammal diversity and relative abundance in the Pantanal Matogrossense National Park using environmental DNA (eDNA) metabarcoding, camera trapping and Bayesian multispecies occupancy models. These methods allowed us to evaluate species, site and assemblage‐level responses to fire, accounting for imperfect detection and landscape heterogeneity. Despite the Pantanal being fire‐prone, we observed significant negative effects on mammals at multiple ecological levels, persisting 2 years post‐fire. Species richness declined from 84 species observed pre‐fire to 44 observed post‐fire. eDNA metabarcoding identified 38 species (23 exclusively), while camera traps recorded 21 species (6 exclusively). A significant negative correlation was found between burned area proportion and both species richness and aggregated relative abundance per site. Impacts were severe on large‐bodied, threatened species, such as the giant armadillo ( Priodontes maximus ), jaguar ( Panthera onca ) and lowland tapir ( Tapirus terrestris ). They experienced significant declines in relative abundance, highlighting the vulnerability of megafauna to severe wildfires. The combination of eDNA and camera trapping proved essential for capturing the full extent of biodiversity impacts in post‐fire landscapes. Synthesis and applications . Our findings highlight the severe and lasting consequences of the 2020 wildfires, observed 2 years after the event, with habitat loss and direct mortality leading to population declines for both forest‐dwelling and open‐habitat species. The complementary use of eDNA metabarcoding and camera trapping enhances biodiversity assessments, though gaps in reference databases remain. These results emphasize the urgent need for adaptive management strategies to mitigate fire impacts, restore habitats and bolster the Pantanal's resilience. Effective governance, stakeholder collaboration and integrated fire management policies are crucial for safeguarding this globally significant wetland.

Fragmentation and habitat loss driven by agricultural expansion have significantly affected bird ecology. Additionally, the growing use of agrochemicals impacts ecosystems and avian communities. Tools such as isotopic analysis provide reliable proxies for assessing organisms' habitat use and diet, and can also reflect environmental alterations, such as increased input of agrochemicals and shifts in baseline resources. By employing stable isotope analysis of carbon (δ¹³C) and nitrogen (δ¹⁵N) on bird feathers over an extensive timescale, we investigated whether human impacts have changed their habitat use, diet, and feather development in two key regions of the Brazilian Atlantic Forest: the Pernambuco and Serra do Mar areas of endemism. We analyzed feathers from 1778 museum specimens, categorized by region, trophic guild and temporal groups (historical and modern). Furthermore, we examined fault bars in the wing and tail feathers of 856 specimens to assess changes in feather development. In Serra do Mar, comparisons showed a significant decline in δ¹⁵N over time, while δ¹³C remained stable. These findings suggest that, in addition to habitat loss, agrochemical runoff may indirectly affect bird communities in this region, known for its high agricultural activity. In contrast, isotopic changes in Pernambuco were significant for only a few species, suggesting that habitat use and diet shifts in this region are primarily driven by fragmentation and forest loss. Moreover, we noted a decline in feather quality over time, underscoring the negative effects of human stressors on feather development across the Atlantic Forest birds.

Natural history data are essential for understanding species' ecological roles, supporting applied research and guiding conservation efforts. However, significant gaps in ecological knowledge limit our understanding, requiring complementary approaches to bridge them. Using an integrative analytical framework, we explored multiple niche dimensions of poorly known co‐occurring xenarthran insectivores, uncovering shared and unique roles within this guild. Our findings revealed divergences among most species' pairs across three niche dimensions while emphasising distinct ecological roles within a three‐tier trophic structure. Habitat use was strongly influenced by resource availability, with species exploiting both natural and anthropogenic habitats, reflecting a double‐edged trade‐off. Spatial and trophic patterns mirrored each other, demonstrating the interconnectedness of diet and habitat use, with activity patterns further aligning with these trends. These findings challenge assumptions of ecological redundancy and highlight the complexity of guild‐level interactions, emphasising critical knowledge gaps in biodiversity and its essential contributions to global ecosystem processes.

Land‐use changes and related anthropogenic pressures are responsible for biodiversity declines and threaten the provision of ecosystem services, especially in tropical forests. Seed dispersal and predation, for example, are especially important ecological processes for shaping plant diversity and composition; however, they can be strongly affected by such changes. Understanding factors that limit seed removal and, consequently, the final seed fate in human‐modified landscapes is vital to enhancing our knowledge of ecosystem functioning. By using structural equation models, we evaluated the direct and indirect effects of landscape structure, anthropogenic stressors, and the abundance of terrestrial mammals on seed removal patterns of Eschweilera ovata (Lecythidaceae), a common large‐seeded species, in 18 Atlantic Forest fragments in southern Bahia, Brazil. We used camera traps to record potential seed‐removing mammals and spool line experiments to assess the ultimate fate of the seeds. We reveal a direct effect of patch size on the percentage of seeds removed, with seed removal decreasing in larger forest fragments. Our results also demonstrated a negative effect of human population density on mammal abundance; although a direct effect of mammals on seed removal was not detected. We, therefore, recommend that anthropogenic pressures should be mitigated to enhance the recovery of mammals in fragmented forest landscapes and that further research incorporate other potential predictors to better elucidate the complex patterns of seed removal in tropical forests.

The expansion of large-scale agriculture has profoundly transformed natural ecosystems, particularly in tropical biomes like the Brazilian Cerrado. As one of Brazil’s most active agricultural frontiers, the Cerrado – especially in its northern portion – is rapidly shrinking. Although modified landscapes generally support lower biodiversity than pristine areas, small remnants of native vegetation remain vital for conservation. Using camera traps, we monitored medium and large-sized mammals across an agricultural mosaic in the Cerrado between Bahia and Tocantins, Brazil, in a landscape dominated by soybean crops. We surveyed seven sites over four campaigns (2020–2024), totaling 15,858 trap-days, and recorded 32 native mammals, four domestic, and one exotic species. Twelve species are threatened in Bahia, including Chrysocyon brachyurus, Panthera onca, Tapirus terrestris, and Tolypeutes tricinctus. Additionally, Leopardus braccatus and Blastocerus dichotomus are nationally threatened, indicating regional listings may increase. Cerdocyon thous, Subulo gouazoubira, and C. brachyurus were the most frequently recorded species, while exotic (Sus scrofa) and domestic (Canis lupus familiaris) species were also widespread. Assemblages shared only ~16% of species, with nine detected exclusively at four sites. Although sites with greater sampling effort had more similar compositions, species richness per campaign was not significantly correlated with effort (Adj-R2 = 0.004, p = 0.32) or the amount of native vegetation (Adj-R2 = 0.06, p = 0.08), suggesting other factors are shaping assemblage structure. Rarefaction curves did not reach an asymptote at any site; however, extrapolation suggests species accumulation will stabilize with modest additional effort at two sites, while others may yield more species. Overall, the study area harbors 74% of the mammal species expected in the Cerrado of Bahia, with total richness comparable to preserved and protected areas. Nonetheless, site-level richness was relatively low, despite a high proportion of threatened species (27–37%). These results underscore the conservation value of small vegetation remnants in human-modified landscapes, even under intensive agriculture. However, reconciling agricultural expansion with biodiversity conservation remains essential to ensuring long-term species persistence.

The environmental DNA (eDNA) metabarcoding is a methodology that, from environmental samples such as soil, water, air, and others, enables the simultaneous identification of multiple species, thus allowing for large-scale mapping of biological diversity in a specific study area. Due to its non-invasive sampling approach, where species are detected from the traces they leave in the environment, eliminating the need to isolate and capture organisms, eDNA metabarcoding emerges as a valuable tool in conservation strategies. This study aims to explore the use of eDNA methodology for biodiversity monitoring and environmental impact assessment caused by the 2020 megafire in the Pantanal of Brazil, focusing on vertebrates. Environmental samples were collected at two protected areas and their surrounding areas, Taiamã Ecological Station (TES) and Pantanal Matogrossense National Park (PMNP), Mato Grosso, Brazil. We identified in TES, 27 mammals, 56 fishes, 12 birds, 4 amphibians, and 4 reptiles, while in PMNP, 43 mammals, 45 fishes, 126 birds, 19 amphibians, and 11 reptiles. Soil sampling proved to be more efficient compared to water sampling: 26 species were exclusively identified in soil samples, while 9 were attributed to water samples. Here, we demonstrated that the primer 12SV5 only a superior efficacy in identifying mammal and herpetofauna species compared to the other markers used (16Smam and MiBird). Moreover, we confirmed the complementary role of eDNA alongside camera trapping, and its advantage to estimate species richness with a single field expedition. We stress the need to optimize sample collection methods for the target group and to reduce the influence of contamination and water flow. This study highlights the importance of eDNA methodology as a crucial tool for biodiversity monitoring and environmental impact assessment, enabling rapid access to biodiversity and long-term monitoring.

Habitat loss and fragmentation are pervasive processes driving the disappearance of populations and species in the Neotropical region. Since species loss may translate into functional loss, assessing changes in the composition of assemblages’ functional traits might improve our understanding of the ecological roles played by species and ecosystem functioning. Here, we investigate how landscape structure and composition impact the functional diversity of terrestrial mammals in 18 forest patches composing eight protected areas in Southern Brazil. We used functional diversity (FD) based on dietary, physical, and behavioral traits and species vulnerability to extinction. We determined which landscape variables (patch size, proportions of forest and sugarcane, and patch isolation) most influenced mammal FD values by using a both-direction stepwise model selection from a linear global model. Finally, we evaluated the role of trophic guilds in explaining the variation in the FD values using a Principal Component Analysis. Between 2012 and 2017, using camera traps, we recorded 26 native medium- and large-sized mammals throughout the protected areas, of which 6 are regionally threatened, and 5 domestic/exotic species. Richness among the forest patches varied from 4 to 24 species (9.05 ± 5.83), while the FD values varied from 1.29 to 6.59 (2.62 ± 1.51). FD variation was best explained by patch size, which exhibited a strong positive correlation (adjusted R² = 0.55, slope = 0.67, p < 0.001). Insectivores and frugivores presented the highest correlation with patch size, explaining most of the variation in the FD values. Our findings strengthen the paramount role of large protected areas in maintaining mammal diversity and their ecological functions in human-modified landscapes.