The Atlantic Forest is one of the most threatened tropical forests in the world. Many species have declined and become isolated because of pervasive forest loss and degradation. Here we assess the current population status of Atlantic Forest tree species from Santa Catarina state in southern Brazil to inform conservation policies and future management and protection. We used a novel methodology to generate automated conservation assessments from forest surveys and herbaria data, based on IUCN criteria A, B, C and D. We assessed more than 500 tree species whose populations are considered threatened. Population size reduction (i.e. IUCN criterion A) was the main indicator of threat, followed by restricted geographical range (criterion B). We observed population reductions of over 50% over three generations in more than 60% of the assessments. We recommend including taxonomically verified herbaria data to improve the accuracy of conservation assessments. The results obtained here can be used to identify important and potential regions for creating protected areas and implementing forest restoration programmes.

Despite significant efforts to assess conservation status, many endemic plants in Brazil remain largely unstudied, including Stachytarpheta, a genus of Verbenaceae with 90 species in the country, of which 82 are endemic. Working with the Brazilian National Center for Plant Conservation, we evaluated all endemic Stachytarpheta for the IUCN Red List. We concluded that 57% of endemic species are threatened (Critically Endangered, Endangered, Vulnerable), 6% are Near Threatened, 22% are Least Concern and 10% are Data Deficient. Threatened species are found exclusively in the Cerrado, Caatinga and Atlantic Forest biomes, where they face threats from livestock farming and ranching, agroindustry, mining and an increased frequency and intensity of wildfires. These species predominantly grow in campos rupestres and savannahs, especially in the Espinhaço Range in Bahia and Minas Gerais states and Chapada dos Veadeiros in Goiás state. At least 68% of the threatened species have one record within a protected area. We highlight the importance of Chapada Diamantina in Bahia and the Diamantina Plateau in Minas Gerais within the Espinhaço Range for the conservation of threatened and unprotected species. This study underscores the important role of taxonomists in the assessment of threatened species, emphasizes the need for further field surveys to gather key information about Data Deficient species and highlights the restricted distribution of several Stachytarpheta species in Brazil.

We report the rediscovery of two endemic tree species of the genus Myrcia (Myrtaceae) in the Brazilian Atlantic Forest in 2021–2022. Both Myrcia colpodes and Myrcia rubiginosa were previously known from a small number of specimens collected mostly in the 19th century in the Metropolitan Region of Rio de Janeiro state in Brazil. Living specimens had not been recorded since 1958 and 2005, respectively. We provide here photographic documentation and updated risk assessments for both species, which will be submitted to IUCN for a formal assessment. Our findings illustrate that rare species that have not been collected for long periods can sometimes be found in plain sight in urban forest fragments. We also highlight the importance of protected areas for the conservation of forest trees, in particular rediscovered species. We recommend a number of conservation actions and encourage the Brazilian government, scientific institutions and civil society to acknowledge the importance of these species and to act to safeguard their future.

Biological invasions can impact the dynamics of ecological processes. For primates of the genus Callithrix, congeneric introductions and hybridization are one of the greatest threats to native species. Three species of Callithrix have been recorded in Rio Doce State Park in south-east Brazil: the Endangered native buffy-tufted-ear marmoset Callithrix aurita and two introduced marmosets, the Geoffroy’s tufted-ear marmoset Callithrix geoffroyi and the black-pencilled marmoset Callithrix penicillata, but their relative abundance was unknown. We used the call playback method and adapted N-mixture models to estimate the abundance and of these marmosets in relation to canopy cover, tree circumference, tree density, number of lianas and epiphytes per tree, distances to nearest forest edge, road, tourist area and urban area, and detection probability in relation to survey effort, mean daily precipitation and temperature. We recorded 139 individuals (0.12 individuals/ha), all hybrids except for one C. aurita. Marmoset abundance was higher close to the forest edge, possibly as a result of the greater availability of food and shelter there. Detection probability was positively correlated with daily precipitation, most probably because marmosets foraged more actively when humidity was high. The situation in Rio Doce State Park is critical, with high hybridization levels and potential local extinction of C. aurita. We recommend that a management plan to conserve the remaining C. aurita is implemented urgently.

Begonia larorum is a threatened plant species endemic to Alcatrazes Island, south-east Brazil, which had not been recorded since its discovery in the 1920s. Here we report its rediscovery after more than a century since the first and only collection. In February 2024, we found a single individual in the forest understorey and successfully propagated it ex situ. Later that year we located a population of 19 individuals in an open area of vegetation prone to fires and invasive grasses and we obtained the first colour photographs of the species. Given its restricted range and the threats to its survival, we recommend the species be assessed for inclusion on the global IUCN Red List in addition to maintaining its Critically Endangered status at national level on the Red List of Brazilian Flora. We also propose in situ and ex situ conservation actions.

The bush dog Speothos venaticus, a short-legged, medium-sized Neotropical canid, remains elusive despite its wide geographical range. We present the first documented occurrence of this species within Rio Doce State Park, Minas Gerais state, Brazil. This Park is a unique, well-preserved area with a diverse array of mammal species, a rarity in the fragmented Atlantic Forest. We recorded the bush dog after 7,744 camera-trap days near Lagoa dos Patos, one of the Park’s lakes. This new record is a significant range extension for the species within the Atlantic Forest of Minas Gerais state, as the nearest known record is c. 420 km to the south. The new record is the northernmost documented occurrence of the bush dog in the Brazilian Atlantic Forest. This finding is a significant addition to the Park’s mammalian carnivore community, and underscores its importance as high-quality habitat for rare species such as the bush dog, and its value for scientific research and biodiversity conservation.