Data from: Dryness is accelerating degradation of vulnerable shrublands in semiarid Mediterranean environments

Semiarid Mediterranean regions are highly susceptible to desertification processes. This study investigated the influence of increasing climate aridity in explaining the decline in vegetation cover in highly vulnerable gypsum semiarid shrublands of the Mediterranean region. For this purpose, we have used time series of the percentage of vegetation coverage obtained from remote sensing imagery (Landsat satellites). We found a dominant trend toward decreased vegetation cover, mainly in summer and in areas affected by the most severe water stress conditions (low precipitation, higher evapotranspiration rates and sun-exposed slopes). We show that past human management and current climate trends interact with local environmental conditions to determine the occurrence of vegetation degradation processes. The results suggest that degradation could be a consequence of the past overexploitation that has characterized this area (and many others in the Mediterranean region), but increased aridity, mainly related to global warming, may be triggering and/or accelerating the degradation processes. The observed pattern may be an early warning of processes potentially affecting more areas of the Mediterranean, according to the most up to date climate change models for the 21st century.

半干旱地中海地区极易受到荒漠化进程的影响。本研究针对地中海地区高脆弱性石膏质半干旱灌丛的植被覆盖度下降问题，探究了气候干旱化加剧对该现象的解释作用。为此，我们采用了源自陆地卫星（Landsat）遥感影像的植被覆盖度时间序列数据。研究结果显示，植被覆盖度整体呈下降趋势，该趋势在夏季以及受最严重水分胁迫的区域（低降水、高蒸散速率的阳坡）尤为显著。本研究表明，过往人类经营管理活动与当前气候趋势，会同当地环境条件共同作用，决定植被退化过程的发生。研究结果指出，该区域（以及地中海地区诸多其他区域）曾经历的过度开发，或是当前植被退化的根源，但与全球变暖相关的干旱化加剧，可能正在触发并/或加速这一退化进程。结合21世纪最新的气候变化模型来看，本次观测到的变化模式，或为潜在影响地中海地区更多区域的荒漠化过程的早期预警信号。