Vulnerability of bird species in highly fragmented forests of southern Brazil: implications for conservation

The seasonal semideciduous forest (SSF) is the most threatened vegetation type of Parana state. Protecting large extensions of pristine forest is essential to prevent biodiversity loss, but evaluating the potential of anthropogenic areas in maintaining biodiversity is important in highly fragmented landscapes. Here, we studied the avifauna of Parana SSF in several habitats (RE, pristine forest considered as reference sites; LF, large forest fragments; MF, middle-sized forest fragments; SF, small forest fragments; UF, urban forest fragments; AF, agricultural fields; RA, reforestation areas) aiming to investigate which are the most vulnerable species in this vegetation type. In order to do so, we categorized each species according to habitat specialization, level of threat, and level of sensitivity to forest fragmentation. We also measured the similarity in bird species composition among six habitat categories with different types of anthropogenic disturbance (LF, MF, SF, UF, AF, and RA). We recorded 368 terrestrial bird species, of which 41 were considered to be vulnerable due to being forest specialist birds that were also sensitive and/or threatened. Sensitive and/or threatened species were rarely found in UF, AF, and RA (1–3 species). Therefore, large forests such as RE are of vital importance to bird species conservation. The similarity in bird species composition among LF, MF, and SF indicates that general ecological functions of birds could be similar in these habitats, suggesting that the conservation of forest fragments is important for the maintenance of bird community functionality in the present Parana SSF.