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This study evaluated the influence of vegetation structure on bird diversity, guilds, and the richness and composition of species in different successional stages of the subtropical Atlantic rain forest. Much of the land that was formerly agricultural in the Brazilian Atlantic rain forest region is now given over to secondary forests. The habitat structure of these successional forests vary and are influenced by time, historical use and local variables, all of which affect bird assemblies. Sampling of bird species was carried out through audio-visual point counts conducted in forests varying from six years after abandonment to old-growth areas. Forests in which the point counts were conducted were further classified into initial, intermediate and advanced stages according to 11 vegetation structural variables, through cluster analyses. The study found that bird richness and diversity were similar between initial and intermediate stages, but higher in advanced areas. Bird species composition differed between the initial and advanced stages, whereas the guild composition of initial forests differed in both intermediate and advanced stages. Late successional forests had more heterogeneous habitats, and some species and guilds were found only in this stage. However, bird diversity and species and guild composition were similar in intermediate and advanced forests, emphasizing the importance of successional forests for conservation efforts, especially when they are located near old-growth forests and conservation units. The recovery patterns of the successional forests studied indicate a great potential for the natural regeneration of the Atlantic rain forest, at least in areas where slash-and-burn agriculture was the previous landuse.Keywords: avifauna; habitat modification; secondary forests; vegetation structure. RESUMOEste estudo avaliou a influência da estrutura da vegetação sobre a diversidade, riqueza e composição de espécies e guildas de aves em florestas sucessionais na Mata Atlântica subtropical. Grande parte das áreas agrícolas que cobriam as regiões da Mata Atlântica são atualmente florestas secundárias, podendo variar em estrutura de habitat conforme o histórico de uso e variáveis locais, influenciando as assembleias de aves. A amostragem da avifauna foi realizada pelo método áudio-visual em pontos de escuta em florestas com seis anos de regeneração após o abandono a áreas antigas. Florestas em cada ponto de escuta foram posteriormente classificadas em estágios inicial, intermediário e avançado de acordo com 11 variáveis estruturais da vegetação, através da análise de agrupamento. A riqueza e diversidade de aves foram similares entre os estágios inicial e intermediário, mas maiores no estágio avançado. A composição de espécies diferiu somente entre os estágios inicial e avançado, enquanto a composição de guildas do estágio inicial diferiu dos estágios intermediário e avançado. Florestas tardias foram mais heterogêneas em termos de habitat, e algumas espécies de aves e guildas foram registradas so...

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Abstract. We report the rediscovery of the hummingbird Heliodoxa rubricauda (Boddaert, 1783) in the Brazilian state of Rio Grande do Sul after nearly 130 years without confirmed records. We captured 3 males and 1 female, and found 2 other birds (including an immature) at 3 sites in the municipalities of São Francisco de Paula and Cambará do Sul, in the northeast of the state. All records were at the top of the Southern Brazilian Plateau escarpment, at altitudes of about 900 m and near the southern limit of the Atlantic Forest.

Abstract:Sampling the full diversity of interactions in an ecological community is a highly intensive effort. Recent studies have demonstrated that many network metrics are sensitive to both sampling effort and network size. Here, we develop a statistical framework, based on bootstrap resampling, that aims to assess sampling sufficiency for some of the most widely used metrics in network ecology, namely connectance, nestedness (NODF-nested overlap and decreasing fill) and modularity (using the QuaBiMo algorithm). Our framework can generate confidence intervals for each network metric with increasing sample size (i.e., the number of sampled interaction events, or number of sampled individuals), which can be used to evaluate sampling sufficiency. The sample is considered sufficient when the confidence limits reach stability or lie within an acceptable level of precision for the aims of the study. We illustrate our framework with data from three quantitative networks of plant and frugivorous birds, varying in size from 16 to 115 species, and 17 to 2,745 interactions. These data sets illustrate that, for the same dataset, sampling sufficiency may be reached at different sample sizes depending on the metric of interest. The bootstrap confidence limits reached stability for the two largest networks, but were wide and unstable with increasing sample size for all three metrics estimated based on the smallest network. The bootstrap method is useful to empirical ecologists to indicate the minimum number of interactions necessary to reach sampling sufficiency for a specific network metric. It is also useful to compare sampling techniques of networks in their capacity to reach sampling sufficiency. Our method is general enough to be applied to different types of metrics and networks.

Aim We evaluated the predation interactions between Moenkhausia sanctaefilomenae and periphytic algae, in the presence or absence of an intermediate consumer (zooplankton). We tested the following hypotheses using a microcosms experiment: 1) fish consume zooplankton when available, therefore reducing algae consumption and increasing algal biomass; 2) fish consume the same algal species in the presence or absence of zooplankton; 3) species from the low-profile of the periphytic algal matrix are less consumed; 4) there is no difference in the nestedness of the networks between treatments, but the network in the treatment with zooplankton is modular; 5) the treatment with zooplankton shows higher interaction diversity, evenness and specialization degree. Methods The microcosms were separated in three treatments, control (no herbivores), T1 with periphytic algae and fish, and T2 with periphytic algae, fish and zooplankton. After seven days of experiment, the stomach contents were analyzed and quantified according to the algal profiles of the periphytic matrix. We also used the individual-resource network to investigate the differences in the individuals’ diet preferences between treatments. Results The fish diet did not differ between food webs with zooplankton presence or absence. They fed more on the algal medium profile, which also predominated in the control. The main food items were the diatoms Ulnaria ulna and Achnanthidium minutissimum. The interaction network results showed that the two treatments presented network modularity, and T2 (with zooplankton) presented nested network, in addition to showing greater interaction diversity and evenness, and less specialization of interactions. Conclusions Moenkhausia sanctaefilomenae can take advantage of a more abundant resource, and the presence or not of zooplankton did not alter the herbivory interaction. Considering the individual-resource network patterns, individuals of fish showed differences in how they share resources between treatments, with presence of opportunistic and selective individuals, and distinct distribution and diversity of interactions in the presence of zooplankton.