Understanding how birds use vegetation to obtain food resources has implications for habitat conservation and management. Restinga is a poorly known and threatened tropical habitat, associated to the Atlantic forest, that could benefit from this kind of information to know which plants can be used and dispersed by birds that can help on the maintenance of this habitat. Frugivorous and insectivorous birds are important components of tropical ecosystems, such as restinga. To provide more information regarding the ecology of restinga, we studied the feeding behavior and spatial use of this vegetation by birds at Restinga de Jurubatiba National Park, southeastern Brazil. We found that feeding behavior was similar to that recorded for the same species in other vegetation types. In addition, spatial use of the restinga vegetation by the most abundant species did not overlap greatly, except for two insectivorous species that used different foraging maneuvers and two frugivorous birds that foraged in flocks. The two most abundant species were generalists in their diet and were capable of feeding at the ground level on sand substrate. Resumo: O conhecimento das estratégias de uso da vegetação pela fauna para forrageio tem implicações para conservação e manejo de habitats. Restinga é um ambiente tropical, associado à Mata Atlântica, ameaçado e ainda pouco conhecido que poderia se beneficiar desse tipo de informação para conhecer quais espécies de plantas podem ser utilizadas e dispersas por aves que atuem na manutenção deste habitat. Aves frugívoras e insetívoras são importantes componentes de ecossistemas tropicais, como a restinga. Para fornecer mais informações sobre a ecologia da restinga, nós estudamos o comportamento de forrageio e o uso do espaço das aves no Parque Nacional da Restinga de Jurubatiba, sudeste do Brasil. Nós encontramos que os comportamentos de forrageio foram similares àqueles registrados para as mesmas espécies em outros ambientes. Além disso, o uso do espaço da vegetação de restinga pelas espécies mais abundantes não apresentou grande sobreposição, exceto por duas espécies insetívoras que usaram manobras de forrageio diferentes e duas aves frugívoras que forragearam em bando. As duas espécies mais abundantes foram generalistas em suas dietas e foram capazes de forragear no chão sobre areia nua. Palavras-chave: Mata Atlântica, comportamento, dieta, Mimus gilvus, Zonotrichia capensis.

Structural and floristic components of vegetation and fruit production were examined to evaluate the relative importance of each vegetation aspect on patterns of habitat use and to determine whether differences in degree of frugivory would affect sensitivity of birds to vegetation components. Abundances of 12 bird species were quantified in four different habitat types in the Southeastern Atlantic rain forest of Brazil using captures with mist nets. Structural and floristic traits and fruit production were sampled within plots along the mist net lines. Best explanations for the variation in species abundance were obtained by different combinations of the vegetation components (generalized linear models, Akaike information criterion; R2 mean values = 0.48, Δ AICc= 0). Although each species had a particular preference for some vegetation variables, floristic components stood out in those relationships, generating models with a stronger explanatory capacity (R2 > 0.40) and higher levels of empirical support (Δ AICc= minimum values). The variation in bird sensitivities to the floristic component was associated with bird dependence on a fruit diet: there was a correlation between the explanatory capacity of models built with only floristic composition and a species' degree of frugivory (Spearman rank correlation, r= 0.66, P= 0.04), indicating that floristics had a higher effect in more frugivorous birds. For the other vegetation components, there was no clear pattern with statistical support. These results indicate that sensitivities of bird species to vegetation aspects are associated with their dependence on a fruit diet.

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We studied the contribution of understory frugivorous birds to the seed inflow into a late successional Atlantic forest patch in southeastern Brazil. Five sampling units were established in the study site, each composed of a line of six mist nets and two adjacent plots containing six seed traps. Immigrant seed species were more frequent in seed traps during the rainy season, when fruit production was higher. On the other hand, the frequency of occurrence of immigrant seed species found in fecal samples of the understory frugivores was higher during the dry season. Although understory frugivorous birds were not responsible for the temporal pattern of the seed rain, they can play an important role in bringing edge plant species that will eventually colonize forest gaps, contributing to forest patch dynamics.

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ABSTRACT. Restinga occurs as a narrow band of coastal habitats throughout the Atlantic Forest, although it presents considerable variation in vegetation structure, which likely contributes to heterogeneity in species inhabiting this endangered ecosystem. The goal of this study is to examine how variation in vegetation and abiotic conditions in the restinga ecosystem may contribute to heterogeneity of bird communities in Restinga de Jurubatiba, Brazil. Temperature, relative humidity, and vegetation structure were sampled to characterize four sites (dry forest, flooded forest, open scrub and closed scrub). Birds were sampled using observations, mist-netting and voice recordings. Results indicate that major differences of all variables occur between forest and scrub in both vegetation and birds. In addition, differences also exist within forests and within scrub, resulting in considerable heterogeneity among sampled areas. Scrub sites were richer in bird species (n = 58) than forest sites (n = 41), while closed scrub had the most species (n = 49). Also, 64% (47 of 73) of bird species were exclusive to forest or scrub habitats. Scrub habitats were more similar to each other than forest habitats. Normalized Difference Vegetation Index (NDVI) calculated from satellite images distinguished scrub sites and may be useful to monitor changes in vegetation patches through time. The restinga ecosystem is quite heterogeneous with considerable turnover in bird species composition and differences in vegetation structure. Forest strips may serve as connectors on the landscape and to help maintain species diversity and conservation of forest species. Also, this highly dynamic ecosystem, which includes a mosaic of habitat types, likely promotes resilience of bird populations under changing conditions.

Restingas are considered stressful habitats associated with the Brazilian Atlantic forest, and their ecological interactions are poorly known. The goal of the present study was to determine the potential role of frugivorous birds as seed dispersers in a restinga habitat. Data were collected in Parque Nacional da Restinga de Jurubatiba, southeastern Brazil, where the main physiognomy (Open Clusia Formation) is characterized by the presence of patches of vegetation covering 20 to 48 % of the sandy soil and reaching a height of 5 m. Birds were captured with mist nets (12 x 2.5 m; 36 mm mesh; 1 680 net-hrs) and had their fecal and regurgitate samples inspected for seeds. Six plant species found in these bird samples were studied. The germination of seeds obtained from plants was compared to those from the birds. Both groups of seeds were set on Petri dishes at room temperature and washed when infected with fungi. In general, there was no effect on germination rate, and the effect on germination speed was negative. Germination of seeds from Pilosocereus arrabidae treated by the birds seemed to be influenced by storage of defecated seeds, while few Miconia cinnamomifolia seeds both from plants and from birds germinated. Ocotea notata presented a great variation in time to the onset of germination, perhaps an advantage against dissecation. Aechmea nudicaulis, Clusia hilariana and Erythroxylum subsessile probably take advantage of the arrival to favorable microhabitats, not by the gut effect on the seeds. All plant species studied are numerically important for the community and some of them are main actors in the succession of vegetation patches. Among the birds, Mimus gilvus is an important resident species, endemic to restingas in Brazil, while Turdus amaurochalinus is a visitor and may be important for plants that fructify during its passage by the study site. Although the effect of pulp removal was only tested for one species (Achmea nudicaulis) in the present study, we confirmed that the tested effect of restinga frugivorous birds on seed germination was generally null. Although there is a need for more detailed studies on specific animal-plant interactions on this habitat, the overall effect of the birds on seed dispersal in restinga is probably positive.