Chen Mingyang, Henderson Mark, Liu Binhui, Zhou Wanying, Ma Rong, Huang Weiwei, Dou Zeyu
College of Forestry, The Northeast Forestry University, Harbin, China.
Mills College, Northeastern University, Oakland, CA, United States.
Front Plant Sci. 2024 Dec 2;15:1476576. doi: 10.3389/fpls.2024.1476576. eCollection 2024.
Global warming has significantly altered plant phenology by advancing the timing of leaf emergence, impacting vegetation productivity and adaptability. Winter and spring temperatures have commonly been used to explain spring phenology shifts, but we still lack a solid understanding of the effects of interactions between conditions in different seasons. This study utilizes normalized difference vegetation index (NDVI) and meteorological data to examine the effects of changes in winter and spring temperatures and precipitation on the start of the vegetation growing season (SOS) at high latitudes in China from 1982 to 2015. We found that SOS in Northeast China, as a whole, showed a weak advancing trend (moving earlier in the year), but with obvious regional differences. Even within the same vegetation type, changes in SOS were faster in the cold north (1.9 days/decade) and the cold and dry northwest (1.6 days/decade) than the regional averages for deciduous needleleaf forests (DNF; 1.2 days/decade) and grasslands (0.6 days/decade). Increases in spring temperatures dominate forest SOS advancement, while grassland SOS is mainly influenced by winter and spring precipitation. Decreases in winter minimum temperature (T) enhance the spring temperature sensitivity of SOS. The way that winter precipitation regulates the spring temperature sensitivity of SOS differs among vegetation types: increasing sensitivity in grasslands but suppressing it in DNF. The moderating effects of winter conditions account for the greatest part of the regional differences in the magnitude of change in SOS. Our findings highlight that, although rising spring temperatures significantly affect SOS, winter T and precipitation are crucial for understanding spatial SOS differences, particularly in cold, arid high-latitude regions. Winter conditions play an essential role in regulating the response of vegetation SOS to spring climate at high latitudes. These results suggest that considering the moderating effect of winter climate can facilitate more accurate predictions of temperature-driven phenological changes under future climate change.
全球变暖通过提前叶片出现时间显著改变了植物物候，影响了植被生产力和适应性。冬季和春季温度通常被用来解释春季物候变化，但我们对不同季节条件之间相互作用的影响仍缺乏深入了解。本研究利用归一化植被指数（NDVI）和气象数据，研究了1982年至2015年中国高纬度地区冬季和春季温度及降水变化对植被生长季开始时间（SOS）的影响。我们发现，中国东北地区的SOS总体呈微弱提前趋势（年份提前），但存在明显的区域差异。即使在同一植被类型内，寒冷的北方（1.9天/十年）和寒冷干燥的西北（1.6天/十年）的SOS变化速度也比落叶针叶林（DNF；1.2天/十年）和草原（0.6天/十年）的区域平均速度快。春季温度升高主导了森林SOS的提前，而草原SOS主要受冬季和春季降水影响。冬季最低温度（T）的降低增强了SOS对春季温度的敏感性。冬季降水调节SOS春季温度敏感性的方式因植被类型而异：在草原上增加敏感性，而在DNF中抑制敏感性。冬季条件的调节作用在SOS变化幅度的区域差异中占最大部分。我们的研究结果表明，尽管春季温度上升显著影响SOS，但冬季T和降水对于理解SOS的空间差异至关重要，特别是在寒冷、干旱的高纬度地区。冬季条件在调节高纬度地区植被SOS对春季气候的响应中起着至关重要的作用。这些结果表明，考虑冬季气候的调节作用有助于更准确地预测未来气候变化下温度驱动的物候变化。
