Declining global warming effects on the phenology of spring leaf unfolding
Declining global warming effects on the phenology of spring leaf unfolding
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DOI：
10.1038/nature15402
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发表时间：
2015-10-01
期刊：
影响因子：
64.8
通讯作者：
Janssens, Ivan A.
中科院分区：
文献类型：
--
作者：
Fu, Yongshuo H.;Zhao, Hongfang;Janssens, Ivan A.
早春叶片展开是植物对气候变暖的一种常见反应（1-4）。许多落叶树种需要低温来解除休眠，而与变暖相关的低温减少可能会抵消叶片展开对变暖的反应（5，6）。然而，这方面的经验证据仅限于气候控制室中的树苗或树枝（7，8）。通过对1,245个地点的7种主要欧洲树种的叶片展开进行长期原位观察，我们发现，从1980年到2013年，所有监测树种的叶片展开对气候变暖的明显反应（S-T，以每摄氏度变暖的叶片展开提前天数表示）显着下降。所有物种和地点的平均S-T下降了40%，从1980-1994年的4.0 +/- 1.8天摄氏度下降到1999-2013年的2.3 +/- 1.6天摄氏度。下降的S-T也被基于寒冷的物候模型模拟，尽管下降幅度（24-30%）弱于Answedin situ。S-T的减少可能部分归因于冷却的减少。尽管如此，其他机制也可能有一定的作用，如“光周期限制”机制，可能成为最终限制时，叶片展开日期发生在赛季过早。我们的研究结果提供了经验证据，下降的S-T，但也表明，在未来的预测强劲的冬季变暖可能会进一步减少S-T，因此导致在树木春季物候提前放缓。
Earlier spring leaf unfolding is a frequently observed response of plants to climate warming(1-4). Many deciduous tree species require chilling for dormancy release, and warming-related reductions in chillingmay counteract the advance of leaf unfolding in response to warming(5,6). Empirical evidence for this, however, is limited to saplings or twigs in climate-controlled chambers(7,8). Using long-termin situ observations of leaf unfolding for seven dominant European tree species at 1,245 sites, here we show that the apparent response of leaf unfolding to climate warming (S-T, expressed in days advance of leaf unfolding per degrees C warming) has significantly decreased from 1980 to 2013 in all monitored tree species. Averaged across all species and sites, S-T decreased by 40% from 4.0 +/- 1.8 days degrees C-1 during 1980-1994 to 2.3 +/- 1.6 days degrees C-1 during 1999-2013. The declining S-T was also simulated by chilling-based phenology models, albeit with a weaker decline (24-30%) than observedin situ. The reduction in S-T is likely to be partly attributable to reduced chilling. Nonetheless, other mechanisms may also have a role, such as 'photo-period limitation' mechanisms that may become ultimately limiting when leaf unfolding dates occur too early in the season. Our results provide empirical evidence for a declining S-T, but also suggest that the predicted strong winter warming in the future may further reduce S-T and therefore result in a slow down in the advance of tree spring phenology.