Assessing temperature sensitivity of subalpine shrub phenology in semi-arid mountain regions of China
Assessing temperature sensitivity of subalpine shrub phenology in semi-arid mountain regions of China
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DOI：
10.1016/j.agrformet.2015.06.013
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发表时间：
2015-11-15
影响因子：
6.2
通讯作者：
Liu, Hu
中科院分区：
文献类型：
--
作者：
He, Zhibin;Du, Jun;Liu, Hu
亚高山灌木正在经历，或经历了深刻的变化，最近的气候异常的力量，如改变物候期的时间生态位和与环境条件的动态相互作用。作为高海拔生态区的寒冷生物群落，它们对当前和未来气候变化的潜在脆弱性日益受到关注。在这项研究中，我们检索了时间序列（2000-2013）的卫星为基础的物候转变（营养生长的开始和偏移）的亚高山灌木在五个单独的网站在中国西北部祁连山。我们的目标是确定出叶的时间和叶下降的气候限制，并预测这些物候模式在未来的气候条件下。为实现上述目标，采用单变量和多变量时间序列模型研究了这些区域物候事件与气候变量之间的关系，并基于IPCCs排放情景特别报告（SRES）A2和B2的最佳预测模型对未来20 a的物候动态进行了预测。我们的研究结果一般揭示了站点依赖的物候气候关系，其中涉及的平均或最低温度在相应的月份发生的即时物候响应，并在前几个月和季节的滞后累积气候效应。一定时期的平均气温是植物生长的重要限制因子。然而，我们的研究结果也提供了证据的最低温度控制的物候事件在亚高山灌丛的发展，可能是由于在春季和秋季霜冻风险的频率密切相关。在未来的气候条件下，根据海拔高度的不同，预计每个研究地点的活跃生长季节将总体延长。因此，灌木的净碳吸收将受益于温度的升高。(C)2015 Elsevier B. V.版权所有。
Subalpine shrubs are undergoing, or have experienced profound changes by force of recent climate anomalies, such as the alteration in temporal niche of phenophases and the dynamic interaction with ambient conditions. As cold biomes in high-altitude ecoregions, they have drawn a growing concern of the potential vulnerability to current and future climate change. In this study, we retrieved the time series (2000-2013) of satellite-based phenological transitions (the onset and offset of vegetative growth) for subalpine shrubs at five individual sites in the Qilian Mountains in northwestern China. Our goals were to identify the climatic constraints on the timing of leaf-out and leaf-fall, and to project these phenological patterns under the future climate conditions. To achieve these goals, the relationships between these regional phenological events and climate variables were investigated with univariate and multivariate time series models, and the future phenological dynamics were forecasted for two decades based on the best predictive models under the A2 and B2 of IPCCs Special Report on Emissions Scenarios (SRES). Our results generally revealed site-dependent phenology-climate relationships, which involved an immediate phenological response to the mean or minimum temperature in the corresponding month of occurrence, and a lagged cumulative climate effect across preceding months and seasons. Average temperature during a certain period has been demonstrated as an important limiting factor for plant growth. However, our results also provided evidence for the minimum temperature controls of the development of phenological events in subalpine shrublands, possibly due to a close association with the frequency of frost risk in spring and autumn. Under future climate conditions, an overall lengthening of the active growing season is expected at each of the study sites depending on elevation. Consequently, net carbon uptake by shrubs will benefit from the increased temperature. (C) 2015 Elsevier B.V. All rights reserved.