Amazonian forests are extraordinarily diverse, but the estimated species richness is very much debated. Here, we apply an ensemble of parametric estimators and a novel technique that includes conspecific spatial aggregation to an extended database of forest plots with up-to-date taxonomy. We show that the species abundance distribution of Amazonia is best approximated by a logseries with aggregated individuals, where aggregation increases with rarity. By averaging several methods to estimate total richness, we confirm that over 15,000 tree species are expected to occur in Amazonia. We also show that using ten times the number of plots would result in an increase to just ~50% of those 15,000 estimated species. To get a more complete sample of all tree species, rigorous field campaigns may be needed but the number of trees in Amazonia will remain an estimate for years to come.

Mammalian carnivores are considered a key group in maintaining ecological health and can indicate potential ecological integrity in landscapes where they occur. Carnivores also hold high conservation value and their habitat requirements can guide management and conservation plans. The order Carnivora has 84 species from 8 families in the Neotropical region: Canidae; Felidae; Mephitidae; Mustelidae; Otariidae; Phocidae; Procyonidae; and Ursidae. Herein, we include published and unpublished data on native terrestrial Neotropical carnivores (Canidae; Felidae; Mephitidae; Mustelidae; Procyonidae; and Ursidae). NEOTROPICAL CARNIVORES is a publicly available data set that includes 99,605 data entries from 35,511 unique georeferenced coordinates. Detection/non‐detection and quantitative data were obtained from 1818 to 2018 by researchers, governmental agencies, non‐governmental organizations, and private consultants. Data were collected using several methods including camera trapping, museum collections, roadkill, line transect, and opportunistic records. Literature (peer‐reviewed and grey literature) from Portuguese, Spanish and English were incorporated in this compilation. Most of the data set consists of detection data entries (n = 79,343; 79.7%) but also includes non‐detection data (n = 20,262; 20.3%). Of those, 43.3% also include count data (n = 43,151). The information available in NEOTROPICAL CARNIVORES will contribute to macroecological, ecological, and conservation questions in multiple spatio‐temporal perspectives. As carnivores play key roles in trophic interactions, a better understanding of their distribution and habitat requirements are essential to establish conservation management plans and safeguard the future ecological health of Neotropical ecosystems. Our data paper, combined with other large‐scale data sets, has great potential to clarify species distribution and related ecological processes within the Neotropics. There are no copyright restrictions and no restriction for using data from this data paper, as long as the data paper is cited as the source of the information used. We also request that users inform us of how they intend to use the data.

Over a century after Wallace’s proposition of the riverine barrier hypothesis, the role of rivers in the diversification of species remains a matter of interest in Amazon biogeography. Amazonian rivers, in particular those large and fast flowing rivers, are widely recognized to act as barriers to the dispersal of some organisms. However, the extent to which primate species changes across interfluves (β-diversity) in response to river features remains to be explicitly tested. In this study, we examine how river characteristics affect the variation in taxonomic and phylogenetic β-diversity to elucidate the ecological processes behind the differences in primate assemblages between neighboring interfluves in the Brazilian Amazonia. We compiled International Union for Conservation of Nature (IUCN) distribution maps of 80 river-bounded primate species in 10 interfluves separated by major rivers throughout the Brazilian Amazonia. We assessed both the taxonomic (disregarding phylogenetic relationships between species) and phylogenetic β-diversities. We applied multiple linear models to evaluate whether annual discharge, sinuosity, and reflectance (as a proxy for amount of sediments) in each river or river section that separates neighboring interfluves make rivers effective barriers to primates. We found that mean discharge has a positive effect, while both sinuosity and amount of sediments have negative effects on primate β-diversity. These variables have significant effects on total taxonomic and phylogenetic β-diversity between neighboring interfluves, and their species turnover components. River features, however, have no effect on species richness differences. Genera are capable of traversing almost all interfluves, but species are replaced by others in opposite interfluves. Discharge affected both small- and large-sized primate total β-diversity, but sinuosity only affected large-sized primate assemblages in neighboring interfluves. Our results indicate that although Amazonian rivers act as barriers for many primate species, this barrier effect seems limited to the short/medium time scales, as primate lineages are able to cross them over long-time scales.

Aim To investigate the geographic patterns and ecological correlates in the geographic distribution of the most common tree dispersal modes in Amazonia (endozoochory, synzoochory, anemochory and hydrochory). We examined if the proportional abundance of these dispersal modes could be explained by the availability of dispersal agents (disperser‐availability hypothesis) and/or the availability of resources for constructing zoochorous fruits (resource‐availability hypothesis). Time period Tree‐inventory plots established between 1934 and 2019. Major taxa studied Trees with a diameter at breast height (DBH) ≥ 9.55 cm. Location Amazonia, here defined as the lowland rain forests of the Amazon River basin and the Guiana Shield. Methods We assigned dispersal modes to a total of 5433 species and morphospecies within 1877 tree‐inventory plots across terra‐firme, seasonally flooded, and permanently flooded forests. We investigated geographic patterns in the proportional abundance of dispersal modes. We performed an abundance‐weighted mean pairwise distance (MPD) test and fit generalized linear models (GLMs) to explain the geographic distribution of dispersal modes. Results Anemochory was significantly, positively associated with mean annual wind speed, and hydrochory was significantly higher in flooded forests. Dispersal modes did not consistently show significant associations with the availability of resources for constructing zoochorous fruits. A lower dissimilarity in dispersal modes, resulting from a higher dominance of endozoochory, occurred in terra‐firme forests (excluding podzols) compared to flooded forests. Main conclusions The disperser‐availability hypothesis was well supported for abiotic dispersal modes (anemochory and hydrochory). The availability of resources for constructing zoochorous fruits seems an unlikely explanation for the distribution of dispersal modes in Amazonia. The association between frugivores and the proportional abundance of zoochory requires further research, as tree recruitment not only depends on dispersal vectors but also on conditions that favour or limit seedling recruitment across forest types.

ABSTRACT. Density, population size and primate conservation in Atlantic forest fragments in the south region of Minas Gerais, Brazil. The purpose of this work is to estimate the density and the population size of four primate species [Alouatta clamitans Cabrera, 1940; Callicebus nigrifrons (Spix, 1823); Callithrix aurita (É. Geoffroy, 1812); Cebus nigritus (Goldfuss, 1809)] which occur in a fragment of Atlantic forest of approximately 350 hectares located in Pouso Alegre, state of Minas Gerais, as well as to give subsidies for the conservation of those species in the area. The population surveying was carried out through the distance sampling method in linear transects (Distance Sampling). Data were collected between April and August 2008 from four transects deployed in the study area. The density and population size were calculated using the software Distance 5.0 and were estimated in 23,83 ± 9,78 ind./km² for Callicebus nigrifrons, 14,76 ± 5,92 ind./km² for Callithrix aurita and 7,71 ± 2,13 ind./km² for Cebus nigritus. The population size was estimated in 83,0 ± 34,0 individuals for C. nigrifrons, 52,0 ± 20,8 individuals for Callithrix aurita and 27,0 ± 7,4 individuals for Cebus nigritus. With regard to the howler monkey (A. clamitans), it was stated out that just a group with six individuals survive in the area. In conclusion, the chances for these isolated populations to survive are slim due to the risk of stochastic events. The creation of ecological corridors connecting the study area to the other fragments, besides the translocation of individuals from other areas of the Atlantic forest to this region, could provide alternatives to ensure the viability of these populations in a long-term. Therefore, it is necessary to consolidate public policies in Pouso Alegre that lead to the creation, enlargement and management of conservation units and incentives for the adoption of productive practices based on sustainability in these areas of ecological interest. Cabrera, 1940; Callicebus nigrifrons (Spix, 1823); Callithrix aurita (É. Geoffroy, 1812); Cebus nigritus (Goldfuss, 1809)] que ocorrem em um fragmento de Mata Atlântica de aproximadamente 350 ha, localizado no município de Pouso Alegre, estado de Minas Gerais e reunir subsídios para a conservação dessas espécies na região. O levantamento populacional foi realizado através do método de amostragem de distâncias em transecções lineares (Distance Sampling). Os dados foram coletados entre os meses de abril e agosto de 2008 a partir de quatro transecções implantadas na área de estudo. Os cálculos de densidade e tamanho populacional foram realizados empregando-se o programa Distance 5.0. As densidades foram estimadas em 23,83 ± 9,78 ind./km² para Callicebus nigrifrons, 14,76 ± 5,92 ind./km² para Callithrix aurita e 7,71 ± 2,13 ind./km² para Cebus nigritus. O tamanho populacional foi estimado em 83,0 ± 34,0 indivíduos para C. nigrifrons, 52,0 ± 20,8 indivíduos para Callithrix aurita e 27,0 ± 7,4 indivíduos para Cebus nigritus. Com relação ao bugio (A. guariba clam...