[1]SONG Menglai,CHEN Haitao,DING Han,et al.Temporal and Spatial Variation Characteristic and Influencing Factors of Vegetation Coverage in Tianjin During 1990—2020[J].Research of Soil and Water Conservation,2023,30(01):154-163.[doi:10.13869/j.cnki.rswc.2023.01.015]
Copy
Research of Soil and Water Conservation[ISSN 1005-3409/CN 61-1272/P] Volume:
30
Number of periods:
2023 01
Page number:
154-163
Column:
Public date:
2023-01-10
- Title:
-
Temporal and Spatial Variation Characteristic and Influencing Factors of Vegetation Coverage in Tianjin During 1990—2020
- Author(s):
-
SONG Menglai1, CHEN Haitao1, DING Han1, CUI Naixin1, KANG Gelin2, WANG Yuqiu1
-
(1.College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China; 2.National Engineering Laboratory for Port Hydraulic Construction Technology, Key Laboratory of Engineering Sediment, Tianjin Research Institute for Water Transport Engineering, ministry of Transport, Tianjin 300456, China)
-
- Keywords:
-
fraction of vegetation coverage; Google Earth Engine; random forest; Tianjin City
- CLC:
-
Q948
- DOI:
-
10.13869/j.cnki.rswc.2023.01.015
- Abstract:
-
Fraction of vegetation coverage(FVC)is an important parameter for regional ecological environment quality. Revealing the temporal and spatial variation characteristic of long-term FVC and identifying the dominant influencing factor can provide a scientific reference for evaluating vegetation condition. Taking Tianjin as the research area, we extracted FVC by combining the pixel binary model based on Landsat images of the Google Earth Engine(GEE)during 1990—2020. The temporal and spatial variation trend of FVC was analyzed by linear regression and F test. Fluctuation change and future trend of FVC were analyzed by coefficient of variation and Hurst index. The order of feature importance and partial dependency plots of random forest(RF)were applied to quantify the non-linear response relationship between FVC and the same period of climate factors(mean annual temperature, annual precipitation)and human activity factors(land use, population density), then we further analyzed the spatial influencing magnitude of multi-factor coupling on FVC. The results showed that:(1)In terms of time, FVC presented the downward trend during 1990—2020 with a significant decrease of 0.001 5(p<0.05); FVC showed the significant decrease during 1990—2012(p<0.05); however, no significant change was observed after 2012(p>0.05); classifications of FVC displayed significant differences in time series; the proportions of low, medium-low and medium FVC showed significant increase(p<0.05), while the proportions of medium-high and high FVC showed significant decrease consistently(p<0.05);(2)spatially, FVC showed a spatial distribution pattern that gradually increased from six districts to outside and the types were mainly high(49.68%); FVC in about 32.62% of the research area showed a significant decrease trend which mainly distributed in four suburban districts and Binhai New Area; FVC in about 27.42% of the research area showed a significant increase trend which mainly distributed in outer suburban districts and six districts; In the past 30 years, the proportion of degraded area was larger than improved area and the future trend of FVC would be dominant degeneration;(3)the influence of human activities(57.27%)on FVC was much higher than the climate factors(42.73%), of which land use was the dominant factor; compared with the single climate factor, the interaction between temperature and precipitation could enhance the spatial influencing magnitude of FVC. This research can reveal the driving factors of FVC and provide a reference for policy-making on vegetation protection.