Atlantic Forest: Brazilian biome with most endangered species
The Atlantic Forest is the Brazilian biome with the largest number of endangered plant and animal species in the country, according to a survey released on Wednesday (May 24), in Rio de Janeiro, by Brazil´s statistic agency IBGE. 
The survey is based on the lists of fauna - prepared by the Chico Mendes Institute for Biodiversity Conservation (ICMBio) - and flora, elaborated by the Botanical Garden of Rio de Janeiro (JBRJ), both released last year.
The study involved the assessment of 21,456 animal and plant species across all Brazilian biomes, which accounts for approximately 12 percent of the country's biodiversity. Through the data collected, experts categorized the species according to their threat situation, in ascending order of concern: vulnerable (VU), endangered (EN), and critically endangered (CR).
Species categorized as "Data Deficient (DD)", "Least Concern (LC)", and "Near Threatened (NT)" are not considered threatened. The NT category serves as the intermediary step before a species is classified as "Vulnerable (VU)".
Evaluation
Among the six Brazilian biomes, the Atlantic Forest stands out with the highest number of assessed species, reaching 11,811. It is also the region with the greatest concentration of threatened species, accounting for 2,845 individuals, equivalent to nearly a quarter (24.1%) of the total. According to IBGE, 43 percent of all threatened species find their home within the Atlantic Forest. Moreover, this biome has the highest number of declared extinct species, with eight documented cases. The most recent addition to this list is the bell-legged stilt (Boana cymbalum), as reported by IBGE.
IBGE researcher Leonardo Bergamini elucidates that the Atlantic Forest's threatened species prominence can be attributed to multiple factors. Firstly, it is linked to the intrinsic characteristics of the biome itself, encompassing numerous endemic and geographically restricted species. Additionally, the extensive history of human occupation and subsequent loss of native areas in the Atlantic Forest play a significant role. Furthermore, the concentration of institutions and research centers within this biome contributes to greater availability of information regarding its biodiversity, facilitating more accurate assessments of species' extinction risks.
Following the Atlantic Forest, the Cerrado emerges as the next significant biome, with 7,385 species evaluated. Among these, 1,199 species (16.2%) are classified as at risk. Other biomes also exhibit noteworthy percentages of threatened species among those assessed. In the Caatinga biome, 3,220 species (14.9%) fall under the threatened category, while the Pampas biome accounts for 229 species (13.7%) facing similar risks.
The Amazon biome stands out as having the lowest number of threatened species among those assessed, with only 503 species (6%). Similarly, the Pantanal biome exhibits a relatively low proportion of threatened species, with 1,825 species (4.1%) falling into this category.
Evaluated species
IBGE also reported that the total number of species assessed in 2022 increased compared to the list drawn up in 2014. Plants went from 9 percent of the total (4,304) to 15 percent (7,517), while animals rose from 10 percent (12,009) to 11 percent (13,939).
"This is a positive stride towards obtaining a more comprehensive understanding of the status of species in Brazil and, consequently, the condition of the ecosystems in which they thrive," stated Bergamini.
The number of endangered species has dropped both in flora and fauna. The plant species at risk of extinction went from 47.4 percent in 2014 to 42.7 percent in 2022. Threatened animals, on the other hand, fell from 9.8 percent to 9 percent in the period.
Both flora and fauna have witnessed a decline in the number of endangered species. The percentage of plant species at risk of extinction decreased from 47.4 percent in 2014 to 42.7 percent in 2022. Similarly, the proportion of threatened animal species decreased from 9.8 percent to 9 percent over the same period.
The drop, according to IBGE, can be explained by the increase in the number of species assessed.
Environments
In terms of environmental distribution, the majority of species examined in both fauna and flora belong to terrestrial habitats, accounting for 65 percent in 2014 and rising to 70 percent in 2022. Freshwater species experienced a slight decrease from 39 percent to 37 percent, while marine species also exhibited a minor decline from 16 percent to 15 percent.
