Analyzing nonlinear variations in terrestrial vegetation in China during 1982–2012

Abstract

Quantifying the long-term trends of changes in terrestrial vegetation on a large scale is an effective method for detecting the effects of global environmental change. In view of the trend towards overall restoration and local degradation of terrestrial vegetation in China, it is necessary to pay attention to the spatial processes of vegetative restoration or degradation, as well as to clarify the temporal and spatial characteristics of vegetative growth in greater geographical detail. However, traditional linear regression analysis has some drawbacks when describing ecological processes. Combining nonparametric linear regression analysis with high-order nonlinear fitting, the temporal and spatial characteristics of terrestrial vegetative growth in China during 1982-2012 were detected using the third generation of Global Inventory Modeling and Mapping Studies (GIMMS3g) dataset. The results showed that high-order curves could be effective. The region joining Ordos City and Shaanxi Gansu Ningxia on the Loess Plateau may have experienced restoration-degradation-restoration processes of vegetative growth. In the Daloushan Mountains, degradation-restoration processes of vegetative growth may have occurred, and the occurrence of several hidden vegetative growth processes was located in different regions of eastern China. Changes in cultivated vegetation were inconsistent with changes in other vegetation types. In southern China and some high-altitude areas, temperature was the primary driver of vegetative growth on an interannual scale, while in the north, the effect of rainfall was more significant. Nevertheless, the influence of climate on vegetation activity in large urban areas was weak. The trend types of degradation-restoration processes in several regions were inconsistent with the implements of regional land development and protection strategy. Thus, the role of human activity cannot be ignored. In future studies, it will be still necessary to quantify the effects of human management on spatial patterns, develop trend-fitting methods, and explore more refined methods of analyzing the driving forces affecting large-scale changes in vegetative growth.

Impacts of Climate on Spatiotemporal Variations in Vegetation NDVI from 1982–2015 in Inner Mongolia, China

“…These results agree with those obtained by Yang et al [65]. This change rate is larger than the change rate in China (0.007/10 a from 1982 to 2011) [66,67], and it is also larger than the Loess Plateau (0.025/10 a, from 1982 to 2013) [66] and Tibetan Plateau (0.004/10 a from 1982 to 2012) [68]. The slope is the change rate of vegetation growth, and P represents the significance degree.…”

Effects of land use changes on the nonlinear trends of net primary productivity in arid and semiarid areas, China

“…Our study showed that the region joining Shaanxi, Gansu, and Ningxia on the Loess Plateau experienced a decrease to increase trend of NPP, while the high mountains in Xinjiang exhibited an increase to decrease trend (Figure 2c), which are inconsistent with the monotonic increase trend claimed by Wu, Yu, Zhang, Du, and Zhang (2018). The trend reversal from decrease to increase in the region joining Shaanxi, Gansu, and Ningxia on the Loess Plateau was predominantly attributed to land development and ecological protection efforts (Liu et al, 2015). The extensive cultivation and the rapid development of husbandry industries caused vegetation degradation during the early years of the study period, whereas the implementation of the Grain to Green Program promoted vegetation growth and led to the trend reversal from decrease to increase (Xue et al, 2019).…”

Spatial–Temporal Variation Characteristics of Multiple Meteorological Variables and Vegetation over the Loess Plateau Region

“…The statistical results reveal that the average trends over Loess Plateau during S, S1, and S2 were 0.022/10a, 0.013/10a, and 0.059/10a, respectively. After 2000, the growth rate of vegetation over Loess Plateau was 4.5 times that before 2000, In addition, [35] shows that the vegetation change rate of the whole China during 1982-2012 is 0.002/10a, and the vegetation growth rate of Loess Plateau during S and S2 is 11 and 29.5 times than that of the whole China. From the spatial distribution of NDVI, vegetation decreased in the southern and northern portions of Loess Plateau, especially in area I.…”