Plant height and spatial context influence individual connectivity and specialization on seed dispersers in a tree population.

While network analyses have stimulated a renewed interest in understanding patterns and drivers of specialization within communities, few studies have explored specialization within populations. Thus, in plant populations, causes and consequences of individual variation in their interactions with mutualistic animals remain poorly understood. Studying a Brazilian pepper (Schinus terebinthifolia) population, we measured the extent of individual variation in interactions with seed dispersers and tested whether connectivity (number of seed dispersers) and specialization (exclusiveness of partners) are associated with phenotypic and phenological traits of individuals and their spatial context. We found that: (i) individuals varied broadly in their connectivity and specialization on seed dispersers; (ii) phenotypic traits and spatial context matter more than fruiting duration in determining how many and how exclusive are seed dispersers of an individual; (iii) the individual-based network was nested and indicated that the less connected individuals were shorter, occurred in neighborhoods with fewer fruits, and tended to interact with a subset of the partners of more generalist individuals which, in turn, were taller and inserted in higher fruit density neighborhoods; (iv) modularity indicated the existence of subsets of individuals that interacted disproportionately with distinct groups of partners, which may occur due to differences in bird habitat use across the landscape. Our study underlines a remarkable interindividual variation that is overlooked when interactions are compiled to describe species-level interactions. Traits and spatial contexts that define variation among individuals may have important implications not only for fitness but also for sampling and description of interactions at species level.

ATLANTIC BIRDS: a data set of bird species from the Brazilian Atlantic Forest.

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, on-line 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.