Fragmentation, urbanization and conservation of birds in riparian forests

The objective of this study was to evaluate the influence of the fragmentation and urbanization on the structure and composition of bird communities in riparian forest in São Paulo, Brazil. The work was carried out in six fragments of the riparian forest in the months of June to August in 2016 and 2017. A fixed point method (15min) was used and the number of points varied according to fragment size. Each point was visited three times during each month. The explanatory variables were: (1) landscape scale: highways, urban area, and river distances and fragment size; (2) fragment scale, in an area of 5m radius: average height of trees, number of trees above 2m, number of shrubs <2m, and the percentage of canopy opening. The observations resulted in 87 species of birds belonging to 34 families, the most predominant trophic groups were insectivorous (54%), omnivorous (11.5%) and frugivorous (10.3%). The most representative families were Tyrannidae, Thraupidae and Picidae. The results obtained at the fragment scale showed that the number of trees explained the variation in abundance. The landscape characteristics analyses showed that the size of the area had a positive and linear relationship with total abundance and abundance of frugivorous species. Richness was inversely proportional to the distance from the river. In addition, distance from highways, urban areas, and from the river positively influenced species abundance. In conclusion, the bird community in riparian fragments was impacted by loss of trees above 2m and urbanization, mainly leading to loss of frugivorous species.