Abstract. Climate change and human activities have significant
impacts on terrestrial vegetation. Syria is a typical arid region with a
water-limited ecosystem and has experienced severe social unrest over the
last decades. In this study, changes in vegetation and potential drivers in
Syria are investigated. By using an enhanced vegetation index (EVI), a
general browning trend is found in Syria during 2001–2018, with the EVI
decreasing at a rate of −0.8 × 10−3 yr−1 (p<0.1). The decrease of the EVI is mainly found in the north region, whereas
the west region still maintains an increasing trend. The residual analysis
indicates that besides precipitation, human activities also contribute
significantly to the EVI decrease, which is confirmed by the decrease in
rainfall use efficiency. Moreover, a paired land-use experiment (PLUE)
analysis is carried out in the Khabur River basin where croplands are widely
distributed in adjacent regions of Syria and Turkey. The time series of the
EVIs over these two regions are highly correlated (r=0.8027, p<0.001), indicating that both regions are affected by similar climate
forcing. However, vegetation in Syria and Turkey illustrates contrary
browning (−3 × 10−3 yr−1, p<0.01) and greening
trends (4.5 × 10−3 yr−1, p<0.01), respectively.
Relevant reports have noted that social unrest induced insufficient
irrigation and lack of seeds, fertilizers, pesticides and field management.
Therefore, we concluded that the decline in vegetation in the north Syria is
driven by the change of land management.