Insights on the roles of climate and human activities to vegetation degradation and restoration in Beijing-Tianjin sandstorm source region

Abstract

Evaluating climate and human-induced vegetation change could support managing the sustainability of ecological environment. Based on the Normalized Difference Vegetation Index (NDVI) dataset, meteorological data (temperature, precipitation), land use data and statistical data, this study used a trend quantitative analysis to distinguish the relative roles of climate change and human activities on vegetation degradation and restoration from 1982 to 2015 in Beijing-Tianjin sandstorm source region. Our results demonstrated that the increased vegetation reached 63.8% of the study area during 1982–2015. Using piecewise linear regression method, we identified two turning points within the period 1982–2015 were 1994 and 2004, respectively. By considering the turning points, we found the increasing, decreasing, and increasing trend during 1982–1994, 1995–2004 and 2005–2015, respectively. In 1982–2015, 68.1% of the vegetation change was dominated by the combined effects of climate and human activities, whereas 25.4% was caused by human activities. During 1982–1994, the increasing trend of vegetation was due to favorable climate factors (26.8%) and the combined effects of both (45.4%). In 1995–2004, the vegetation degradation was driven by unreasonable human activities (13%) and the combined effects of unfavorable climate factors and unreasonable human activities (33.1%). However, with the implementation of ecological engineering, the positive human activities (8%) and the combined effects of both (59.1%) were responsible for vegetation restoration during 2005–2015. We noticed that precipitation was the main climate factor limiting regional vegetation change, the sensitivity of vegetation to precipitation was increasing over the study period. Nevertheless, human activities played an increasingly important role in regional vegetation. In particularly, the ecological engineering and increasing precipitation were the main factors for regional vegetation restoration in the past 10 years.