Landscape type and area change from 2000 to 2020
(1)From 2000 to 2010, the change characteristics of landscape type area within the research scope are as follows: forest area decreases by 31.7260 km2, arable land area increases by 19.1651 km2, grassland area decreases by 7.2873 km2, wetland area decreases by 20.4536 km2, water area increases by 24.1112 km2 and artificial surface increases by 16.1907 km2. The changes of landscape types in the study area are as follows: the net area of forest conversion to arable land and grassland is 12.3014 km2 and 23.7927 km2 respectively; The net area of wetland, water area and artificial surface transform into forest is 3.0635 km2, 1.2445 km2 and 0.0602 km2 respectively; The net area of grassland and wetland transform into arable land is 8.7711 km2 and 7.2958 km2 respectively; The net area of arable land transforms into water area and artificial surface is 0.2014 km2 and 9.0019 km2 respectively. During this period, the study area is greatly affected by the urbanization process, the arable land area increases more, the forest area decreases relatively, the wetland area decreases, and the ecological function degrades slightly. (Table 2)
Area (km2 )
|
2010 Type
|
Total for 2000
|
Forest
|
Arable Land
|
Grassland
|
Wetlands
|
Water Area
|
Artificial Surface
|
2000 Type
|
Forest
|
4449.1960
|
82.2055
|
533.7474
|
1.8849
|
7.0716
|
4.6657
|
5078.7711
|
Arable Land
|
69.9041
|
6581.0981
|
73.2963
|
6.3123
|
8.4917
|
39.1253
|
6778.2279
|
Grassland
|
509.9547
|
82.0674
|
1018.4451
|
5.8876
|
19.8954
|
17.8357
|
1654.0860
|
Wetlands
|
4.9484
|
13.6082
|
3.9699
|
503.4648
|
29.8817
|
0.0101
|
555.8832
|
Water Area
|
8.3161
|
8.2903
|
7.2320
|
17.8797
|
292.1685
|
0.4614
|
334.3481
|
Artificial Surface
|
4.7259
|
30.1235
|
10.1079
|
-
|
0.9502
|
251.4090
|
297.3166
|
Total for 2000
|
5047.0453
|
6797.3931
|
1646.7986
|
535.4293
|
358.4592
|
313.5073
|
14698
|
Table 2. Area Transfer Matrix in Reserve from 2000 to 2010
From 2010 to 2020, the area changes of landscape types within the research scope are as follows: forest area decreases by 21.2294 km2, arable land area decreases by 217.543 km2, grassland area decreases by 21.9122 km2, wetland area increases by 237.4112 km2, water area increases by 9.0769 km2 and artificial surface increases by 12.1403 km2. The changes of landscape types in the study area are as follows: the net area of forest transformation to arable land, wetland, water area and artificial surface is 29.0640 km2, 10.0757 km2, 4.0841 km2 and 0.1960 km2 respectively; The net area from grassland to forest is 22.1904 km2; The net area of arable land transforms into grassland, wetland, water area and artificial surface is 8.1281 km2, 208.7429 km2, 2.0921 km2 and 27.6439 km2 respectively. During this period, the arable land area decreases significantly, about 213 km2 of the reduced arable land is transformed into wetland area, and the main increase area is the border Heilongjiang Basin area. (Table 3)
Area (km2 )
|
2020 Type
|
Total for 2010
|
Forest
|
Arable Land
|
Grassland
|
Wetlands
|
Water Area
|
Artificial Surface
|
2010 Type
|
Forest
|
4406.8893
|
94.8103
|
519.0942
|
11.6773
|
10.4644
|
4.3397
|
5047.2752
|
Arable Land
|
65.7464
|
6379.7236
|
79.8451
|
213.0910
|
7.3263
|
52.0560
|
6797.7884
|
Grassland
|
541.2846
|
71.7170
|
1010.2380
|
4.4787
|
9.4855
|
9.5112
|
1646.7150
|
Wetlands
|
1.6016
|
4.3481
|
3.5300
|
502.7510
|
23.3454
|
0.0090
|
535.5853
|
Water Area
|
6.3803
|
5.2342
|
5.9394
|
22.2166
|
317.0017
|
0.5908
|
357.3631
|
Artificial Surface
|
4.1437
|
24.4121
|
6.1560
|
18.9424
|
0.7121
|
259.2204
|
313.5868
|
Total for 2020
|
5026.0459
|
6580.2454
|
1624.8027
|
773.1571
|
368.3355
|
325.7271
|
14698
|
Table 3. Area transfer matrix in reserve from 2010 to 2020.
From the landscape pattern changes in the 20 years from 2000 to 2020, the arable land area has changed greatly, the total area has decreased by nearly 200 km2, the forest area is also decreasing, the wetland area is increasing more, and the area of artificial surface (i.e. construction land) is also increasing. In terms of spatial distribution, the change of agricultural and forestry land is mainly concentrated in the urban intensive areas in the central region. The reduction of forest area caused by human activities, especially the construction of urbanization; The implementation of the protection policy of basic farmland has led to the continuous increase of arable land after 2010. The increase of wetland area is mainly attributed to the implementation of relevant national policies. Planning for the Ecology Protection and Economic Transformation in Da Xing’anling and Xiao Xing’anling (2010-2020), prepared by National Development and Reform Commission and the State Forestry Administration in conjunction with relevant departments, was printed and issued for implementation in 2010 and clearly strengthened the protection and construction of forest ecology and wetlands. The implementation of relevant national policies has curbed the momentum of forest area reduction and increased the area of wetlands. (Fig 2)
Landscape pattern simulation forecast for 2020-2030
Accuracy test
According to the method described in 2.2, the driving factors relate to the change of landscape pattern in the study area are selected through correlation analysis, i.e. three phases of relevant data in 2000, 2010 and 2020, average annual temperature, precipitation, DEM image, road, river, construction land range, etc. The landscape pattern of the study area in 2020 is simulated and predicted, and the simulation and prediction map of landscape pattern in 2020 is obtained.
The accuracy test of landscape pattern simulation in 2020 is as follows: high similarity can be found through the visual interpretation of the 2020 simulation prediction map and the 2020 real map, and the visual interpretation of the images of the simulation results of three typical areas enlarged locally. (Fig 3) After calculation, Kappa coefficient is calculated to be 0.825, which is greater than 0.75, and the FOM index is 0.04, which is less than 0.1, and the reliability of the model simulation is high.
Simulation prediction results
It is verified that the simulation accuracy in 2020 is high, and the landscape pattern in 2030 can be simulated and predicted. The prediction results are shown in Fig 4 and Table 4. Among them, the area change of landscape types within the research scope is predicted as follows: the forest area decreases by 0.0648 km2, the arable land area increases by 1.0368 km2, the grassland area decreases by 0.0972 km2, the wetland area increases by 14.6448 km2, the water area increases by 6.1317 km2, and the artificial surface decreases by 21.6513 km2. The changes of landscape types in the study area are as follows: the net area of forest transformation to arable land, grassland and wetland is 0.0324 km2, 0.0243 km2 and 0.0081 km2 respectively; The net area of arable land transforms into wetland is 0.2025 km2; The net area of grassland, water area and artificial surface transform into arable land is, 0.081 km2, 0.0081 km2 and 1.1178 km2 respectively.
Area (km2 )
|
2030 Type
|
Total for 2020
|
Forest
|
Arable Land
|
Grassland
|
Wetlands
|
Water Area
|
Artificial Surface
|
|
Forest
|
5027.9056
|
0.0567
|
0.0243
|
0.0081
|
-
|
-
|
5027.9947
|
Arable Land
|
0.0243
|
6571.6064
|
-
|
0.0243
|
-
|
0.0081
|
6571.6631
|
Grassland
|
-
|
0.0812
|
1626.3909
|
0.0162
|
0.0081
|
0.0162
|
1626.5124
|
Wetlands
|
-
|
0.0243
|
-
|
775.1538
|
0.0814
|
0.0648
|
775.3243
|
Water Area
|
-
|
0.0081
|
-
|
0.0891
|
370.9071
|
0.0243
|
371.0286
|
Artificial Surface
|
-
|
1.1259
|
-
|
14.4747
|
6.1641
|
304.1145
|
325.8792
|
Total for 2030
|
5027.9299
|
6572.9026
|
1626.4152
|
789.7662
|
377.1607
|
304.2280
|
14698
|
Table 4. Area transfer matrix in reserve from 2020 to 2030.
Landscape pattern change and forecast analysis
Landscape type area change characteristics
From 2010 to 2020 and the forecast for the next 10 years (Fig 5), it can be seen that the forest area is slowly decreasing, and the decreasing momentum will be effectively curbed in the next 10 years; The arable land area shows an increase followed by a decrease and remains stable in the next 10 years; Among other landscape types, wetlands have continued to increase since 2010 and will continue to increase in the next 10 years, while the area of artificial surface shows a decreasing trend.
Landscape pattern change characteristics
(1) Characteristics of the changing landscape pattern in Hegang City
The 20-year time span of the study area and the overall changes of landscape pattern in the next 10 years are shown in Table 5. Among them, the number of patches (NP) shows a significant downward trend in the first 10 years of the study period, then begins to increase and remained basically stable in the next 10 years; Patch density (PD) first decreases and then increases, and the overall patch density will increase slowly in the future; Shannon evenness index (SHEI) has a negative correlation with the changes of patch number and density, that is, it increases first and then decreases, and will basically maintain a relatively stable trend in the future. The results show that from 2000 to 2010, the landscape richness and heterogeneity of Hegang City decreases, and the degree of fragmentation is low; From 2010 to 2030, landscape richness and heterogeneity increases, and the degree of fragmentation is high.
Year
LID
|
Landscape Area
TA
|
Number of Patches
NP
|
Patch Density
PD
|
Largest Patch Index
LPI
|
Landscape Richness
PR
|
Shannon Evenness Index
SHEI
|
2000
|
1474215
|
157292
|
10.6695
|
35.3449
|
6
|
0.6477
|
2010
|
1471269
|
147946
|
10.0557
|
28.1412
|
6
|
0.7021
|
2020
|
1465767
|
155255
|
10.5921
|
34.3237
|
6
|
0.6708
|
2030
|
1465782
|
155285
|
10.5966
|
34.3598
|
6
|
0.6728
|
Table 5. Evolution of landscape patterns in landscape level from 2000 to 2030.
(2) Characteristics of changes in the pattern of agricultural and forestry land and other landscape types
The landscape pattern index of agricultural and forestry land types in Hegang City from 2000 to 2030 is shown in Fig 6.
① Patch density: the smallest is arable land(0.0341), followed by forest, and the maximum is artificial surface(1.2352). This indicates that the fragmentation degree of arable land and forest is low, especially the patch density of forest continues to decrease, and the fragmentation process of forest has been improved. In other landscape types, the patch density of grassland and water area decrease first and then increase, and the grassland increases more, and the degree of fragmentation deepens; Wetlands and artificial surfaces have been gradually decreasing, indicating that the overall fragmentation degree is gradually decreasing.
② Largest patch index: The largest patch index of arable land and forest is similar and significantly larger than that of other landscape types, showing a fluctuating trend of first increasing and then decreasing, which shows that arable land and forest are the dominant landscape types in the study area to a certain extent. In other landscape types, the largest patch index of water area shows a continuous decreasing trend, and the decreasing is very obvious, indicating that its integrity decreases and the degree of fragmentation deepens; Grassland, wetland and artificial surface have been increasing gradually, and the increase of wetland is large, which is consistent with the large increase of its area. Grassland, wetland and artificial surface have been increasing gradually, and the increase of wetland is large, which is consistent with the large increase of its area.
③ Landscape shape index: the landscape shape index of arable land and forest decreases slightly and then increases significantly, and the maximum value appeared in 2030 (17.3426 and 32.7912), indicating that the shape of these two landscape types is relatively complex and the intensity of various disturbances (such as natural conditions and human factors) is large. Other landscape types increase slightly and then decrease, indicating that these landscape types are relatively less affected by external interference.