1985 to 28.1 × 10
3
km
2
in 2015 (Figure 7g), which is signifi-
cantly negatively correlated (
P
<0.01) with the area changes in
lakes. The loss of lake area in the
EPL
, especially in the middle
and lower Yangtze floodplain, can thus be largely attributed to
intensive land reclamation for cultivation and human settle-
ment (Ma
et al.
, 2010, Xie
et al.
, 2017). Additionally, strong
inverse correlations are found between the number of flood-
gates and the relative water area of lakes in the
NPML
,
EPL
, and
YGPL
zones (
P
<0.01). The excessive construction of floodgates
or dams on river systems has greatly altered the natural flow
regimes of rivers through the artificial water regulation, and
subsequently reduced the water discharged into lakes. For
Table 4. Correlation analysis on the relationship between overall changes in relative water area of lakes (
≥
10 km
2
) and climatic and
human factors in the five lake zones from 1985 to 2015. Significant relationship was notated by asterisk signs (*
P
<0.05, **
P
<0.01).
Method Variable
NPML EPL YGPL TPL
IMXL
Xinjiang Inner Mongolia
r
r
r
r
r
r
Correlation analysis
AMT
-0.45 -0.65 -0.68 0.98** 0.66
-0.31
AMP
0.07 -0.35 0.00 0.81* 0.92**
0.24
Irrigation -0.86* -0.98** -0.85* 0.79
0.70
-0.82*
Coal
production
-0.66 -0.80* -0.85* 0.60
0.63
-0.84*
Grazing
-0.85* -0.27 -0.63 -0.13
0.73
-0.94**
Built-up area -0.90** -0.92** -0.81* 0.18
0.20
-0.70
Floodgate -0.88** -0.89** -0.96** 0.75
0.53
-0.41
Figure 7. Changes in climate and human activities in the five lake zones (i.e.,
NPML
,
IMXL
,
TPL
,
EPL
, and
YGPL
) during the past
decades: (a) Annual mean temperature (
AMT
) anomaly, (b) annual mean precipitation (
AMP
) anomaly, (c) human population,
(d) irrigated area, (e) coal production, (f) number of sheep and goats, (g) built-up area, and (h) number of floodgates.
PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING
October 2018
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