Fig 1.
Spatial distribution of the study area and grassland types in China.
The blank areas mark the locations of the study areas on the map of China. Black stars indicate the locations of climate stations, and red triangles represent ground measurement points. Source: Land use and cover data is from the Land Processes Distributed Active Archive Center (LP DAAC, https://lpdaac.usgs.gov). The study areas and the map of China are from National Geomatics Center of China (https://www.ngcc.cn), and the meteorological data are from the China Meteorological Administration (CMA, http://www.nmic.cn).
Table 1.
Parameters for R/S, Ca, and Cb across different grassland types.
Fig 2.
Comparison of field-measured and estimated AGB (g/m2) for (a) 2001 and (b) 2010.
Fig 3.
(a) Spatial distribution of grassland AGB (g/m2); (b) Percentage of area covered by different AGB ranges. Source: Land use and cover data is from the Land Processes Distributed Active Archive Center (LP DAAC, https://lpdaac.usgs.gov). The study areas are from National Geomatics Center of China (https://www.ngcc.cn).
Fig 4.
Seasonal distributions of grassland AGB: (a) Spring, (b) Summer, (c) Autumn, and (d) Winter.
Source: Land use and cover data is from the Land Processes Distributed Active Archive Center (LP DAAC, https://lpdaac.usgs.gov). The study areas are from National Geomatics Center of China (https://www.ngcc.cn).
Fig 5.
Inter-annual variation in AGB for (a) all grassland types and (b) seven main grassland types.
Black, red and blue dotted lines represent changes in grassland AGB over the periods 1981–2015, 1981–2005, and 2005–2015, respectively. The black solid line indicates the mean AGB of 272.72 g/m2 for all grassland types.
Fig 6.
(a) Spatial trends and (b) coefficient of variation of grassland AGB from 1981 to 2015.
These trends highlight the temporal and spatial variability in grassland productivity over the study period. Source: Land use and cover data is from the Land Processes Distributed Active Archive Center (LP DAAC, https://lpdaac.usgs.gov). The study areas are from National Geomatics Center of China (https://www.ngcc.cn).
Fig 7.
Correlation between grassland AGB and key factors: (a) mean annual temperature (T), (b) mean annual precipitation (PPT), (c) vapor pressure deficit (VPD), (d) solar radiation (SR), (e) relative humidity (RH), (f) soil moisture (SM), and (g) grazing intensity (GI).
Categories are as follows: SN = Significant negative, NSN = Non-significant negative, NSP = Non-significant positive. Source: Land use and cover data is from the Land Processes Distributed Active Archive Center (LP DAAC, https://lpdaac.usgs.gov). The study areas are from National Geomatics Center of China (https://www.ngcc.cn).
Fig 8.
Relative importance of driving factors on grassland AGB as assessed by Random Forest analysis.
Fig 9.
Corrections (r values) between grassland AGB and driving factors: (a) air temperature (T), (b) precipitation (PPT), (c) vapor pressure deficit (VPD), (d) solar radiation (SR), (e) relative humidity (RH), (f) soil moisture (SM), and (g) grazing intensity (GI) across different grassland types.