Most tree species rely on vertebrates for seed dispersal, and many vertebrates use fruits as food resources in tropical forests. Therefore, plant-frugivore interactions affect population dynamics and persistence in ecological communities. Plant-frugivore interactions often involve many species, forming networks of interacting plants and animals that play different roles in determining network organization. The network organization is the way interactions are structured in the community, which may have consequences for its ecological and evolutionary dynamics. Some species have greater influences on network organization and may be particularly important to species persistence. We identified the frugivores most important to the organization of networks of plants and frugivorous birds in three contiguous Atlantic forest sites in southeastern Brazil. We found that the species that contributed most to network organization were at higher risk of extinction. Among the main contributors to network organization were two cotingas and a toucan, large-bodied species that disperse seeds from many plants and are particularly vulnerable to habitat loss and hunting. As a consequence, ongoing extinctions may significantly affect the organization of plant-frugivore interactions in the studied system. We hypothesize that the crucial role of some threatened frugivores may occur in other seed dispersal systems in tropical communities, although the association between structural importance and degree of threat may be contingent on peculiarities of local communities and disturbances.

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Forest fragmentation and habitat loss are among the major current extinction causes. Remaining fragments are mostly small, isolated and showing poor quality. Being primarily arboreal, Neotropical primates are generally sensitive to fragmentation effects. Furthermore, primates are involved in complex ecological process. Thus, landscape changes that negatively interfere with primate population dynamic affect the structure, composition, and ultimately the viability of the whole community. We evaluated if fragment size, isolation and visibility and matrix permeability are important for explaining the occurrence of three Neotropical primate species. Employing playback, we verified the presence of Callicebus nigrifrons, Callithrix aurita and Sapajus nigritus at 45 forest fragments around the municipality of Alfenas, Brazil. We classified the landscape and evaluated the metrics through predictive models of occurrence. We selected the best models through Akaike Selection Criterion. Aiming at validating our results, we applied the plausible models to another region (20 fragments at the neighboring municipality of Poço Fundo, Brazil). Twelve models were plausible, and three were validated, two for Sapajus nigritus (Area and Area+Visibility) and one for Callicebus nigrifrons (Area+Matrix). Our results reinforce the contribution of fragment size to maintain biodiversity within highly degraded habitats. At the same time, they stress the importance of including novel, biologically relevant metrics in landscape studies, such as visibility and matrix permeability, which can provide invaluable help for similar studies in the future and on conservation practices in the long run.

General patterns of frugivory in two nearby communities, one suffering greater impact by humans (Sede) than the other (Barra Grande), in Sao Paulo, southeastern Brazil were quantified monthly from January 1999 to March 2000 to assign a conservation value to each species of plant and bird, under the assumption that the more interactions, which is a record of a fruit species eaten by a bird species, a species is part of, the more important it is in the community-wide maintenance of fruit frugivore interactions. Results showed that a total of 68 species of frugivores accounted for 397 interactions unevenly distributed between sites. A total of 103 plant species took part in 397 interactions with birds in both sites. Among other plant families, pioneer and second-growth species formed the bulk of interactions in Sede (Anacardiaceae, Flacourtiaceae, Euphorbiaceae, Rosaceae, Myrsinaceae, Solanaceae and Ulmaceae), whereas canopy and shade-tolerant tree species contributed the most interactions in Barra Grande (Lauraceae, Myrtaceae, Sapindaceae, Symplocaceae, and Loranthaceae). Twenty percent of all recorded bird and plant species in both communities were responsible for the majority of the interactions. The hooded berry-eater, Carpornis cucullatus, a canopy and mid-level species, had the highest number of interactions for both sites combined followed closely by an understorey species, the blue manakin, Chiroxiphia caudata. The same pattern of rank distribution was observed for plant species, except one melastome species, Miconia pusilliflora, in Barra Grande which had more than twice the number of interactions than any of its co-occurring species.

Abstract. South America holds 30% of the world's avifauna, with the Atlantic Forest representing one of the richest regions of the Neotropics. Here we have compiled a data set on Brazilian Atlantic Forest bird occurrence (150,423) and abundance samples (N = 832 bird species; 33,119 bird individuals) using multiple methods, including qualitative surveys, mist nets, point counts, and line transects). We used four main sources of data: museum collections, online databases, literature sources, and unpublished reports. The data set comprises 4,122 localities and data from 1815 to 2017. Most studies were conducted in the Florestas de Interior (1,510 localities) and Serra do Mar (1,280 localities) biogeographic sub-regions. Considering the three main quantitative methods (mist net, point count, and line transect), we compiled abundance data for 745 species in 576 communities. In the data set, the most frequent species were Basileuterus culicivorus, Cyclaris gujanensis, and Conophaga lineata. There were 71 singletons, such as Lipaugus conditus and Calyptura cristata. We suggest that this small number of records reinforces the critical situation of these taxa in the Atlantic Forest. The information provided in this data set can be used for macroecological studies and to foster conservation strategies in this biodiversity hotspot. No copyright restrictions are associated with the data set. Please cite this Data Paper if data are used in publications and teaching events.