How climate change can affect the distribution range and conservation status of an endemic bird from the highlands of eastern Brazil: the case of the Gray-backed Tachuri, Polystictus superciliaris (Aves, Tyrannidae)

Abstract

The Gray-backed Tachuri (Polystictus superciliaris) is a Tyrannidae restricted to eastern Brazilian highlands. Its population and range are still thought to be declining mainly due to habitat loss, caused by land use. We evaluated the impacts on its range (increase or decrease, displacement in latitude and altitude), considering possible effects caused by inappropriate land use and climatic changes. For this purpose, we modeled its current range and estimated its overlap between the predicted area and future scenarios. We also analyzed the efficiency of the Brazilian reserves to the species’ protection. The range established by the Maxent model was 76.1% lower than that available in the literature and presented a decrease in the future. Range contraction for the periods under consideration ranged from 22.5% to 77.3%. The distribution center shifts to the southwest (from 102.5 km to 275.4 km) and to higher elevations (1,102 m to 1,428 m). From the predicted range, 20% are under some kind of human occupation. The Brazilian reserves partially protect the species, with only 12% of its range, from the 44.2% expected. Based on these predictions, and depending on the species’ dispersal ability and adaptation, it may become vulnerable in the period of 2080. This study demonstrates that the most important areas for maintaining populations ofP. superciliaris now and in the future are those located in the ‘Iron Quadrangle’, especially the Serra da Gandarela, where it was partially protected by the recently decreed Gandarela National Park. This region should receive special attention because it is strongly threatened by iron mining in areas relevant for conservation located outside this reserve.