Shifts in bird ranges and conservation priorities in China under climate change

species with reduced ranges are threatened birds, with an average of 19.41% range loss. In the meantime, 31 threatened species may experience an average range expansion of 39.24%. For RCP 8.5, we found that 30 threatened species are projected to experience an average range loss of 33.55% (nine of them would lose more than half of their range), and 31 threatened species would potentially experience an average range expansion of 98.89%. We also found that cli- mate change has more significant effects on the range changes of threatened species than other species, whether for RCP 2.6 (P-value = 0.019) or RCP 8.5 (P-value = 0.046). We divided the studied species into migratory (n = 526) and resident (n = 516) birds, and counted their range changes separately (Table 1). The statistics showed that the impact of climate change on the range of resident species is more intense than that for migratory species, whether under the RCP 2.6 scenario (P-value = 0.0001) or the RCP 8.5 scenario (P-value = 0.026), indicating that the ranges of resident species will experience relatively broad range expansion. For the 190 sample breeding species, the breeding range may change less than the total distribution range, regardless of the climate scenarios (P-value = 0.005 for RCP 2.6, P-value = 0.003 for RCP 8.5; for details, see S1 Fig). We listed the top ten species with the largest range changes, as shown in S2 Fig. More than half of the species with reduced ranges are migratory birds (60% of the species in both RCPs).

It is worth noting that many of them are threatened or endemic to China; notably, Przevalski’s Rosefinch (Urocynchramus pylzowi), Taiwan Blue Magpie (Urocissa caerulea) are endemic spe- cies of China; the Red-crowned Crane (Grus japonensis) is endangered bird species. All of these species would lose more than half of their distribution ranges under RCP 2.6 or more than 80% of their range areas under RCP 8.5. Among them, Short-tailed Parrotbill (Paradoxor- nis davidianus) may go extinct in China (may lose 99.98% range under RCP 8.5). We found that none of the ten species with expanded ranges are threatened or endemic, and all of these species are mainly distributed in southern and southwestern China (see S2 Fig). The distribu- tion ranges of these species were projected to be at least doubled (RCP 2.6) or quadrupled (RCP 8.5). Notably, the range of the Pied Falconet (Microhierax melanoleucus) was projected to increase ten-fold under the RCP8.5 scenario. 3.2 Multidimensional shifts in bird ranges The statistics for the range shifts of different species groups show that under climate change in 2070, more species would move to the north than to the south (P-value = 0.034 for RCP 2.6, P- value = 0.031 for RCP 8.5), with longer average shift distances (P-value = 0.008 for RCP 2.6, P- value = 0.004 for RCP 8.5) across different species groups (Table 2). This result shows that the northward shift of the distribution range may be a holistic trend. The displacement vectors of each bird species range are mapped over the geographical

scope of China and represented in polar form to understand the detailed spatial patterns of range shifts under both the RCP 2.6 and RCP 8.5 scenarios in 2070. For RCP 2.6, the birds Table 1. Statistics of range area changes for bird species in different climate change scenarios. Group Scenario All (n = 1,042) Migratory (n = 526) Resident (n = 516) Range reduce Range expand Range reduce Range expand Range reduce Range expand RCP 2.6 n = 241 n = 801 n = 149 n = 377 n = 92 n = 424 r = -15.7 r = 32.6 r = -16.3 r = 30.4 r = -14.8 r = 34.7 RCP 8.5 n = 244 n = 798 n = 139 n = 387 n = 105 n = 411 r = -27.5 r = 79.8 r = 30.2 r = 76.7 r = -23.8 r = 82.7 n: No. of species; r: Average percentage change in the range. https://doi.org/10.1371/journal.pone.0240225.t001 PLOS ONE Bird range changes call for innovative conservation in China PLOS ONE | https://doi.org/10.1371/journal.pone.0240225 October 8, 2020 6 / 20