Response of vegetation coverage to hydro-thermal change in Inner Mongolia of northern China

ObjectiveOur specific objectives were to track the dynamic changes of vegetation NDVI and its response to climatic factors for different growth stages during recent 32 years (1982-2013) in Inner Mongolia of northern China, which would provide a reference for improving regional ecological environment.

MethodIn this study, with GIMMS3g NDVI (1982-2013) datasets and meteorological data in Inner Mongolia, the spatio-temporal patterns of changes in seasonly NDVI and their linkages with temperature and precipitation were analyzed at regional and pixel scales. Spatial interpolation of meteorological data was achieved using the thin-plate smoothing spline method of Hutchinson.To detect the trends of NDVI and climatic factors, Theil-Sen linear regression was applied. To further explore the climatic factors driving NDVI change during a given period, correlations between NDVI and climatic variables were calculated using Pearson correlation analysis.

ResultThe results showed that the vegetation in Inner Mongolia continuously increased from 1982 to 2013, and correlations were different between NDVI and climatic factors in Inner Mongolia, NDVI mostly had a positive correlation with precipitation, but it was more closely related to pre-precipitation. The correlation between NDVI and temperature was mostly negative correlation. The correlation between NDVI and precipitation was higher than temperature.

ConclusionThe results indicated that the vegetation in Inner Mongolia was continuously improved, and the response of vegetation NDVI to hydro-thermal change for different periods was different in Inner Mongolia. The effect of temperature on vegetation growth was more significant in the northeast region in spring, such as in the eastern and northeastern Hulun beler and the southeast edge of Xilin Gol. The response of NDVI in the central region (e.g. the southwestern Hulun Buir, the most areas of Xilin Gol, the northern Ulanchabu, the most areas of Ordos) was more sensitive to precipitation in summer and autumn, especially lagged effect of vegetation growth on precipitation. Our study suggested that, in ecological restoration and reconstruction project in the future, we should make full use of natural remediation to restore more sustainable vegetation ecosystems; at the same time, in order to avoid land degradation caused by blind large-scale artificial afforestation, it is necessary to consider the current water resources carrying capacity and water supply capacity in the future.