RESTREND-based assessment of factors affecting vegetation dynamics on the Mongolian Plateau

Abstract

The landscape of the Mongolian Plateau (MP) is shaped by both climatic change and human activities. It is noteworthy to monitor regional vegetation dynamics and to discriminate the impacts of climatic and anthropogenic factors on vegetation productivity and diversity. To investigate human- and climate-driven changes in vegetation cover across the MP during 2000−2014, the residual trend analysis (RESTREND) method was applied to analyze the residuals of potential and actual net primary productivity (NPP) and further identify non-climatic effects on vegetation dynamics. Results suggested that the normalized difference vegetation index (NDVI) in growing seasons had been increasing at the rate of 0.002/a in the whole MP during 2000–2015. And potential NPP increased across 71% of the study area, revealed that climate change displayed a generally positive effect on vegetation recovery across the plateau; However, the 53% of the total study area exhibited an decreasing residuals trend, indicated that human activity played a negative role in vegetation recovery. Analysis of the combined effects of climate change and human activities indicated that vegetation recovered in 74% but degraded in 22% of area of the MP. Anthropogenic activity could thus be considered as the main influencing factor of vegetation degradation, while climate change was the main controlling factor of vegetation restoration. Besides, Climatic factors had a similar effect on vegetation dynamics in inner and outer Mongolia, but human activities showed a different pattern with a lesser (greater) effect on vegetation degradation (recovery) in inner Mongolia than in outer Mongolia, respectively.