Replacement of native habitats by tree plantations has increased dramatically in Brazil, resulting in loss of structural components for birds, such as appropriate substrates for foraging and nesting. Tree plantations can also reduce faunal richness and change the composition of bird species. This study evaluated the structure of avian communities in eucalyptus plantations of different ages and in a native forest. We classified species as habitat specialists or generalists, and assessed if the species found in eucalyptus plantations are a subset of the species that occur in the native forest. Forty-one sampling sites were evaluated, with three point counts each, in a native forest and in eucalyptus plantations of four different ages. A total of 71 bird species were identified. Species richness and abundance were higher in the native forest, reflecting the greater heterogeneity of the habitat. The composition of bird species also differed between the native forest and plantations. The species recorded in the plantations represented a subset of the species of the native forest, with a predominance of generalist species. These species are more tolerant of habitat changes and are able to use the plantations. The commercial plantations studied here can serve as a main or occasional habitat for these generalists, especially for those that are semi-dependent on edge and forest. The bird species most affected by silviculture are those that are typical of open grasslands, and those that are highly dependent on well-preserved forests.Keywords: avian fauna, subsets, eucalyptus plantations, native forest. Estrutura de comunidades de aves em plantios de eucalipto:aninhamento como padrão de distribuição de espécies Resumo A substituição de ambientes nativos pela silvicultura está se tornando uma prática cada vez mais comum no Brasil, resultando na perda de componentes estruturais para as espécies de aves, como substratos específicos de forrageamento e nidificação. Esta prática pode reduzir a riqueza e alterar a composição das comunidades de aves. O objetivo deste estudo foi avaliar diferenças na estrutura de comunidades de aves em plantios de eucalipto de diferentes idades e em floresta nativa. Além disso, teve como objetivo classificar espécies em especialistas ou generalistas de habitat e avaliar se espécies encontradas nos plantios de eucalipto representam subconjuntos da floresta nativa. Quarenta e um sítios de amostragem foram avaliados, com três pontos de contagem cada, em uma floresta nativa e em plantios de eucalipto de quatro diferentes idades. Foi identificado um total de 71 espécies de aves. A riqueza de espécies e abundância foram maiores na floresta nativa refletindo a maior heterogeneidade desse habitat. A composição de espécies de aves também diferiu entre a floresta nativa e os plantios. As espécies registradas nos plantios representam um subconjunto das espécies da floresta nativa, o que é explicado pelo predomínio das espécies generalistas. Essas espécies são mais tolerantes às alterações de habitat e...
The present study assessed the variation in bird species composition, and in the proportion of frugivorous and migratory individuals between areas of continuous forest and patches of Araucaria forests in natural grassland areas of southern Brazil. In the grassland-forest mosaic, 703 individuals of 83 bird species were recorded. The proportion of frugivorous and migratory individuals was significantly higher in forest patches and in the interior of continuous forest, compared to forest edges. We suggest that migratory birds are important for the dispersal of seeds from forest interiors to forest patches within the grassland, highlighting the importance of regional processes for the maintenance of local processes, for ecosystem conservation.
Background: Raptor distributions and abundances are poorly known in southern Brazil. Given that raptors have low population densities, methods typically applied to census birds are usually inappropriate for surveying raptors. Roadside surveys allow large areas to be searched at a relatively low cost and are often applied to count raptors. We conducted eight paired roadside surveys (roadside point transects and roadside strip transects of 54.5~58.6 km long) to assess the species richness and abundance of raptors in two grassland landscapes of southern Brazil and to compare results of the two methods. −1 · h −1 ). No significant differences were found in relation to species richness, although five species were exclusively recorded with point transects versus one with strip transects. Conclusions: Roadside point transects may reduce bias due to differences in species detection caused by habitat features and in abundance estimates resulting from survey habitat being disproportional to their availability. Point counts may enhance the quality of the search for raptors in a surveyed area, increasing the detection probability. The choice of survey method depends on the objectives of the study, but our results favor the use of point transects rather than strip transects to survey raptors in open landscapes.
Abstract:Studies of functional diversity can help to understand processes that determine the presence of species in different habitats. Measurement of functional diversity in silviculture areas is important because different functional traits can show different responses to this landscape alteration, and therefore ecological functions can be affected. This study evaluated functional and taxonomic differences in bird assemblages in a native forest and eucalyptus plantations, and also assessed the functional nestedness of the bird species. We censused birds in eucalyptus plantations of four different ages, and also in a native forest. The results showed higher functional and taxonomic diversity of birds in the native forest than in plantations and higher similarity of functional traits between plantations of different ages. The high functional diversity in the native forest indicates a greater variety of functional traits, resulting in greater functional complementarity than in plantations. The association of some traits with the native forest, such as nectarivory and foraging in air, indicates the importance of native habitats in maintaining species and functions related to such traits. Already, species traits in eucalyptus plantations represent a subset of those that were recorded in the native forest, indicating that some functions are maintained in plantations. Our results demonstrate that the species occurrence in the plantations and native forest is determined by species traits. Thus, the maintenance of some functions in plantations is provided, although there is a higher functional diversity in native forest. Piacentini et al. (2015). Nomenclature:
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