College of Geography and Remote Sensing Sciences, Xinjiang University, Urumqi, 830046, China.
College of Geography and Remote Sensing Sciences, Xinjiang University, Urumqi, 830046, China; College of Tourism, Xinjiang University of Finance & Economics, Urumqi, 830012, China.
J Environ Manage. 2023 Oct 15;344:118734. doi: 10.1016/j.jenvman.2023.118734. Epub 2023 Aug 10.
Global warming has exacerbated the threat of drought in Central Asia, amplifying its ecological implications within the region's grassland ecosystems. This has become an increasingly prominent issue that requires attention and action. The temporal link between grassland development and drought is asymmetric. However, a quantitative assessment of the temporal effects of multiscale drought on Central Asian grasslands has yet to be explored. Based on correlation analysis and the coefficient of variation method, this study analysed the cumulative and lag effects of multitimescale drought on grassland NPP (net primary productivity) under different climatic zones, altitudes and water availabilities in Central Asia from 1982 to 2018, and discussed the impact of temporal effects on grassland NPP stability. Our results on the cumulative effects of drought on grasslands indicate the 6.72 months preceding NPP measurement was the duration for which, on average, drought was most strongly correlated with NPP. Additionally, we found a mean lagged effect of 5.36 months, meaning that the monthly drought 5.36 months prior to NPP measurement was, on average, most strongly correlated with NPP. The degree to which grassland NPP was affected by cumulative drought at a given level of water availability was inversely proportional to the number of cumulative drought months. Under different water availabilities, the lagged effect of grassland NPP was stronger in dry areas than in wet areas, and the number of lag months tended to decrease and then increase as the water availability increased. The percentage of areas where grassland NPP was dominated by the cumulative and lagging effects of drought was 30.02% and 69.98%, respectively. The stability of grassland NPP was adversely affected by the drought accumulation effect. The findings of this study contribute to a deeper understanding of the long-term effects of drought on grassland ecosystems. Additionally, it will aid in the development of strategies for mitigating and adapting to drought events, thereby minimizing their negative impacts on agriculture, livestock, and ecosystems.
全球变暖加剧了中亚地区干旱的威胁，放大了其对该地区草原生态系统的生态影响。这已成为一个日益突出的问题，需要引起关注和采取行动。草原发展与干旱之间的时间联系是不对称的。然而，对于多尺度干旱对中亚草原的时间效应的定量评估尚未得到探索。本研究基于相关分析和变异系数方法，分析了 1982 年至 2018 年不同气候带、海拔和水分条件下中亚草原 NPP（净初级生产力）对多时间尺度干旱的累积和滞后效应，并讨论了时间效应对草原 NPP 稳定性的影响。本研究发现，在 NPP 测量前的 6.72 个月是干旱与 NPP 最强烈相关的平均持续时间；此外，我们还发现平均滞后效应为 5.36 个月，这意味着在 NPP 测量前的 5.36 个月，每月的干旱与 NPP 最强烈相关。在一定水分供应水平下，草原 NPP 受到累积干旱影响的程度与累积干旱月数成反比。在不同的水分供应条件下，干旱对草原 NPP 的滞后效应在干旱地区比在湿润地区更强，滞后月数随着水分供应的增加而减少，然后增加。受干旱累积和滞后效应主导的草原 NPP 面积百分比分别为 30.02%和 69.98%。草原 NPP 的稳定性受到干旱积累效应的不利影响。本研究的结果有助于深入了解干旱对草原生态系统的长期影响。此外，这将有助于制定缓解和适应干旱事件的策略，从而将其对农业、畜牧业和生态系统的负面影响降到最低。
