Long-term changes in populations of rainforest birds in the Australia Wet Tropics bioregion: A climate-driven biodiversity emergency

the rainforest bird assemblage in the Australian Wet Tropics bioregion is clearly, and consis- tently, moving uphill in a classic demonstration of the “escalator to extinction” [39]. Overall, we are on track for severe impacts on rainforest birds, particularly the upland spe- cialists. Many of these species are endemic to the region and/or include species that are evolu- tionarily distinct and/or ecologically specialised [43]. Upland bird populations have declined since 2000 by 33% within their core range and the more marginal populations in the midlands have crashed by almost 50% (Fig 3). Midland species, although stable in the cooler uplands at this stage, have declined by >20% within their core area and >40% in the hotter lowlands. Fig 2. Trends in local abundance from 2000 to 2016 based on multi-species indicators for A) lowland specialists, B) midland specialists and C) uplands specialists. Values represent multi-species index with SE (error bars). The overall smoothed trend is represented by the line with shaded area showing the 95% CI for the smoothed trend. https://doi.org/10.1371/journal.pone.0254307.g002 Fig 3. Elevational shifts in local abundance patterns in bird assemblages between 2000 to 2016. Baseline population set to 0 with values above the baseline representing an increase in local population abundance and values below the baseline representing a decline. Values represent the change in local abundance over the

full time period based on the mean multiplicative slope of the multi-species trend with its SE (error bars). See the full abundance trends over time for each combination of elevational band and species group in supplementary material. https://doi.org/10.1371/journal.pone.0254307.g003 PLOS ONE Rainforest birds on escalator to extinction PLOS ONE | https://doi.org/10.1371/journal.pone.0254307 December 22, 2021 7 / 16