On the use of the sensitivity levels of birds to forest fragmentation in the evaluation of the Biotic Integrity: a study case in the north of State of Parana, southern Brazil.

On the use of the sensitivity levels of birds to forest fragmentation in the evaluation of the Biotic Integrity: a study case in the north of State of Parana, southern Brazil. A Index of Biotic Integrity (IBI) is presented based on levels of bird sensitivity to forest fragmentation. Three levels of sensitivity were considered: high, medium, and low. In the present study, 30 bird species were selected, 10 in each level, and the presence/absence of them were verified in 39 forest fragments in the north of the State of Parana, southern Brazil. Based on occurrence data of those selected species, the IBI was calculated in each fragment. The IBI values were influenced by the area of forests fragments (r(2) = 0,34; P < 0,01; F = 18,02). The IBI was also correlated with the species number occurring in the forest fragments (Pearson; r = 0,829, P < 0,01). The largest and more preserved forest fragment presented the highest IBI value (0.85). Therefore, the smaller, isolated and more disturbed forest fragments had the smallest IBI values. It is important to consider that the sensitivity levels of bird species are variable according to different fragmented landscapes; it means that, a previous study to determine the sensitivity levels of bird species is a key factor to an useful IBI. Such procedure can make the IBI an interesting tool for environmental evaluation.