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

For the remaining quarter of the species, 135 species would move to the southwest, and the other 76 species would move to the southeast, both having short average shift distances (Fig 2A2). Whether the migratory group (Fig 2C1 and 2C2) or resident group (Fig 2E1 and 2E2), the number of species in the four quadrants of the polar chart is very similar to the pattern exhibited by all species (Fig 2A2), with no significant differences (P-value = 0.34 for the migra- tory species & all species pairs, P-value = 0.30 for the resident & all species pair). For RCP 8.5, the basic pattern of range shifts remains the same but the migration distances are longer and more variable than those in the previous scenario (Fig 2B1). Compared to those in the RCP 2.6 scenario, the directions of range shifts are more concentrated to the northeast (54.8% of species) in this scenario, with a longer average distance (Fig 2B2). For the migratory group (Fig 2D1 and 2D2), the proportion of species moving to the northeast decrease from 25.7% to 21.3%; for the resident group (Fig 2F1 and 2F2), there would be no significant change in the shift direction pattern, but the shift distances of species may be longer. It is worth noting that 50 species are predicted to move to the north under RCP 2.6 but to the south under RCP 8.5, i.e., in the opposite direction; and 38 species may move to the south under RCP 2.6 but move to the north under RCP 8.5. In both scenarios, most bird species would move to higher elevations by 2070 (Fig 3).

Therefore, the species diversity would increase in mountains and plateaus and decrease in lower elevations. We measured species diversity changes in elevation and found that, if put all Table 2. Statistics for the range shifts of bird species under different climate change scenarios. Group Scenario All (n = 1,042) Migratory (n = 526) Resident (n = 516) To the North To the South To the North To the South To the North To the South RCP 2.6 n = 831 n = 211 n = 459 n = 67 n = 372 n = 144 l = 103.5 l = 43.5 l = 110.6 l = 35.3 l = 94.8 l = 47.3 RCP 8.5 n = 819 n = 223 n = 440 n = 86 n = 379 n = 137 l = 187.0 l = 87.2 l = 202.5 l = 89.5 l = 169.1 l = 85.7 n: No. of species; l: Average shift distance (kilometers). https://doi.org/10.1371/journal.pone.0240225.t002 Fig 2. Range shifts of bird species in 2070. The first line and the second line show the patterns under RCP 2.6 and RCP 8.5, respectively. The three sets of charts arranged in columns show the “all species” group (A-B), “migratory” group (C-D), and “resident” group (E-F) separately. The boundaries are reprinted from Shan Shui Conservation Center under a CC BY 4.0 license, with permission from Xiangying Shi, original copyright 2020. https://doi.org/10.1371/journal.pone.0240225.g002 PLOS ONE Bird range changes call for innovative conservation in China PLOS ONE | https://doi.org/10.1371/journal.pone.0240225 October 8, 2020 8 / 20