The timing of autumn senescence is affected by the timing of spring phenology: implications for predictive models
The timing of autumn senescence is affected by the timing of spring phenology: implications for predictive models
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DOI：
10.1111/gcb.12890
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发表时间：
2015-07-01
影响因子：
11.6
通讯作者：
Richardson, Andrew D.
中科院分区：
文献类型：
--
作者：
Keenan, Trevor F.;Richardson, Andrew D.
秋季衰老调节了生态系统功能的多个方面，并对气候系统产生了相关的反馈。尽管它很重要，但目前对衰老驱动因素的理解是有限的，这导致了对衰老时间以及生长季节长度在未来气候条件下如何变化的预测的广泛传播。最普遍的观点是温度和光周期是主要的控制因素，这表明随着全球气温的上升，秋季生长季节将会延长。在这里，利用二十年来基于地面和卫星的温带落叶林物候观测，我们表明，在整个美国东部，秋季衰老的时间与春季发芽的时间相关。在年复一年的基础上，无论是在个体物种还是在区域尺度上，早春/晚春都与早秋/晚秋衰老有关。我们利用观察到的关系建立了一个新的秋季物候模型。与现有的物候模型相比，该模型预测秋季物候对未来气候变化的潜在响应受到气候变化对春季物候的影响的强烈限制。因此，目前的秋季物候模型可能高估了未来生长季节长度的增加，从而对未来二氧化碳吸收和蒸散的模拟产生影响。
Autumn senescence regulates multiple aspects of ecosystem function, along with associated feedbacks to the climate system. Despite its importance, current understanding of the drivers of senescence is limited, leading to a large spread in predictions of how the timing of senescence, and thus the length of the growing season, will change under future climate conditions. The most commonly held paradigm is that temperature and photoperiod are the primary controls, which suggests a future extension of the autumnal growing season as global temperatures rise. Here, using two decades of ground- and satellite-based observations of temperate deciduous forest phenology, we show that the timing of autumn senescence is correlated with the timing of spring budburst across the entire eastern United States. On a year-to-year basis, an earlier/later spring was associated with an earlier/later autumn senescence, both for individual species and at a regional scale. We use the observed relationship to develop a novel model of autumn phenology. In contrast to current phenology models, this model predicts that the potential response of autumn phenology to future climate change is strongly limited by the impact of climate change on spring phenology. Current models of autumn phenology therefore may overpredict future increases in the length of the growing season, with subsequent impacts for modeling future CO2 uptake and evapotranspiration.