Diversidade de aves em paisagem fragmentada de Mata Atlântica inserida em uma matriz urbana

Abstract

The forest fragmentation is happens when a large and continuous nature habitat area is reduced and divided into two or more fragments. Birds composed the taxonomic group better studied in the research of effects of tropical fragmentation and plays an important role in the ecosystem of rainforests. The urban forest fragments are increasingly common, making necessary a better understanding of their guidelines for care and maintenance as a natural reserve. This study aimed to evaluate generally the differences between in bird communities between Atlantic Forest fragments with urban matrix, with different environmental variables. Specifically aimed to estimate the diversity of birdlife in fragments, analyze the similarity between components of the bird community between areas and check the influence of the size and shape of fragments and their environmental parameters on the richness of birds. The study area was in four forest fragments of Atlantic Forest. To survey the birdlife censuses was conducted through listening points. Vegetation Data were taken along transects of 100 meters. In relation to the density of understory were accounted individuals with height between 50 cm and two meters in plots of 5 x 5 meters. Data related to canopy openness and height were taken into 11 points 10 meters equidistant. As regards the assessment of the similarity of richness between the fragments was done Sorensen Similarity Index. In order to rank the areas studied in relation to the similarity in the structure of the bird community, a dendrogram was made. To evaluate the influence of the vegetation data on the local richness of each area a PCA was undertaken. In this study were cataloged 14 orders, 38 families and 129 species of birds. The fragment Fr4 presented the greatest richness of birds, with 104 species, and Fr2 fragment was the one with the lowest richness, with 49 species. The trophic guild most represented was the insectivores with 62 species followed by thef omnivorous with 37. The Venn diagram indicated that 31 species were common to all areas and that showed the highest number of exclusive species. It was observed that the areas wich had a higher Sorensen Similarity Index were Fr2 x Fr3. In PCA, the axis I was explained by the parameters: canopy openness and understory density. Axis II was explained by canopy height parameter. Analyzing the results we can conclude that all studied areas have a high degree of similarity between them, with a highlight for Fr4. Frugivorous and foraging ground insectivorous birds are the first to be lost in the forest fragmentation, implying that specialist species are the first to be locally extinct. Studies like this, in which is made an analyzes of the structure of the bird community in accordance with the environmental variables and structural fragment are still missing and would greatly help to understand the dynamics of populations in these fragments and the colonization-extinction relation.