Appendix S2. Climate change in China over the past 50 years
To analyze the correlation between change in the distribution of birds and climatic factors, we
analyze the climate change trends in China over the past 50 years. The climate change trends from
1961 to 2013 in China have been reported (China climate change bulletin, Chinese Administration
of Meteorology 2014). However, some climate factors related to change in distribution of birds
have not been analyzed.
Table S1 The climatic factors
No
Climatic factors
unit
1
mean annual air temperature
℃
2
mean air temperature in January
℃
3
mean air temperature in July
℃
4
maximum temperature in warmest month
℃
5
minimum temperature in coldest month
℃
6
sums of cumulative temperature above 0℃
℃
7
the annual mean bio-temperature
℃
8
annual precipitation
mm
9
annual potential evapotranspiration rate
Because bird distributions are likely to have direct or indirect relationships with the macroclimate
and microclimate, the mean annual temperature, mean temperatures in January and July, sum of the
cumulative temperatures above 0°C, minimum temperature in the coldest month and maximum
temperature in the warmest month were calculated. In addition, annual precipitation and the
Holdridge index (Holdridge 1967; Zhange 1993), including the mean annual bio-temperature (BT)
and the annual potential evapotranspiration rate (PER), were selected (See Table S1).
Climatic data for the last 50 years in China were provided by the climate center of the Chinese
Administration of Meteorology as 17,625 grid cells with a resolution of 0.5°×0.5°. These data
included daily air temperature, maximum and minimum temperatures, and daily precipitation. The
climate indices(Table S1) in every grid cells were calculated from 1961 to 2010 using Visual
Fortran (Compaq Visual Fortran Professional Edition 6.5, Compaq Computer Corporation (2000),
Harris County, Texas, US).
y = 0.0313x - 55.957
R2 = 0.7026
a
7.0
6.5
6.0
5.5
21.0
20.5
c
20.0
19.5
19.0
18.5
18.0
17.5
1960
Air temperature
in July(℃)
b y = 0.038x - 84.62
R2 = 0.3016
-8.0
-9.5
1980 1990
year
2000
y = 0.0213x - 23.172
R2 = 0.3544
1970
1980 1990
year
-12.5
1960
2010
Lowest air
temperature( ℃)
1970
2000
2010
26.0
-12.5
1970
1980 1990
year
2000
2010
2000
2010
d y = 0.0456x - 106.1
R2 = 0.3316
-14.0
-15.5
-17.0
-18.5
1960
1970
1980 1990
year
3700
24.0
23.0
y = 0.0254x - 27.423
R2 = 0.3972
CT above 0(℃)
e
25.0
22.0
21.0
1960
1970
1980
year
1990
2000
2010
750
g
700
f
y = 6.0786x - 8705.3
R2 = 0.5731
3500
3300
3100
1960
1970
1980
1990
year
2000
2010
10.3
y = 0.3091x - 1.5455
R2 = 0.0198
h
9.8
BT( ℃)
Preciptation
(mm)
-6.5
-11.0
5.0
1960
Highest air
temperature( ℃)
Air temperature
in January(℃)
Mean air
temperature( ℃)
7.5
650
y = 0.0167x - 23.956
R2 = 0.5761
9.3
8.8
600
550
1960
1970
1980 1990
year
2000
2010
8.3
1960
1970
1980
1990
year
2000
2010
3.0
PER
i
y = -0.0087x + 19.302
R2 = 0.1793
2.5
2.0
1.5
1960
1970
1980
1990
year
2000
2010
Fig S1. Climate change trend over the past 50 years in China
Note: a, b, c, d, e, f, g, h, and i represent the mean annual air temperature, mean air temperature in January, mean air temperature in July,
the highest temperature in the warmest month, the lowest temperature in the coldest month, sums of cumulative temperature above 0°C,
annual precipitation, BT and PER, respectively.
To analyze the relationship between climate change and the changes in bird distributions, the
climate data over the last 50 years were analyzed for each decade from 1961 to 2010. We used
ordinary kriging methods to convert the climate variables into records of bird distributions based on
a digital elevation model (DEM) and produced gridded data for China that were used to overlay the
distribution of birds and climate factors in ARCGIS (Vers. 9.2 for Windows, Esri Corp. (2008),
Redlands, CA, US). Climatic variables were generated for each distribution point for each bird in
each decade.
Over the last 50 years, the mean air temperature in China has generally increased from 5.62°C in
the 1960s to 6.89°C in the 2000s. The air temperature in January showed a similar trend,
increasing by approximately 1.6°C. Similarly, the air temperature in July increased by
approximately 0.82°C. The annual minimum air temperature increased by 1.73°C, and the annual
maximum air temperature increased by 1.05°C. In addition, the cumulative temperatures above
0°C increased from 3289.4°C in the 1960s to 3533.9°C in the 2000s. The annual precipitation in
China has become increasingly variable, showing a decrease from 603.41 mm in the 1960s to
597.64 mm in the 1970s, an increase to 627.52 mm in the 1990s, and then a decrease to 605.09
mm in the 2000s. The BT tracked the cumulative temperature above 0°C from 8.96°C in the 1960s
to 9.62°C in the 2000s. The PER declined from 2.36 in the 1960s to 1.87 in the 1980s and then
increased to 2.06 in the 2000s (Fig. S1).
Our results demonstrate that regional climate change in China displays a trend that is similar to the
changes in the global climate. Over the period from 1880 to 2012, the global average surface
temperatures warmed by 0.85°C [0.65 to 1.06°C] (IPCC 2013). Our results show that over the past
50 years, the annual precipitation in China fluctuated considerably (Fig. S1). The precipitation
averaged over the mid-latitude land areas of the Northern Hemisphere has increased since 1901,
whereas at other latitudes, there is low confidence in the area-averaged long-term positive or
negative trends (IPCC 2013). Our results also indicate that increases in the extreme low and high
temperatures are consistent with global warming (IPCC 2013).
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