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. In order to reach a more reliable conclusion, a comparative 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. Relative reports have reported that social unrest had induced insufficient irrigation and lack of seeds, fertilizers, pesticides and field managements. Therefore, we concluded that the decline of vegetation in the north Syria is driven by the change of land managements.

中文翻译：

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2001-2018 年期间，土地管理对观察到的叙利亚植被褐变做出了重大贡献

摘要。气候变化和人类活动对陆地植被有重大影响。叙利亚是典型的干旱地区，生态系统缺水，过去几十年经历了严重的社会动荡。在这项研究中，调查了叙利亚植被和潜在驱动因素的变化。通过使用增强型植被指数 (EVI)，在 2001-2018 年期间，叙利亚呈现普遍褐化趋势，EVI 以 -0.8 × 10 ^-3  yr ^-1 ( p < 0.1)。EVI 的下降主要集中在北部地区，而西部地区仍保持上升趋势。残差分析表明，除降水外，人类活动对 EVI 的下降也有显着贡献，降水利用效率的下降证实了这一点。为了得出更可靠的结论，在与叙利亚和土耳其相邻地区农田广泛分布的哈布尔河流域进行了比较分析。这两个区域的 EVI 时间序列高度相关（r  = 0.8027，p  < 0.001），表明两个区域都受到相似的气候强迫的影响。然而，叙利亚和土耳其的植被显示相反的褐变（-3 × 10 ^-3  yr^-1 , p  < 0.01) 和绿化趋势 (4.5 × 10 ^-3  yr ^-1 , p  < 0.01)。相关报道称，社会动荡导致灌溉不足，缺乏种子、肥料、杀虫剂和田间管理。因此，我们得出结论，叙利亚北部植被的减少是由土地管理的变化驱动的。