Transpiration from subarctic deciduous woodlands: Environmental controls and contribution to ecosystem evapotranspiration
Transpiration from subarctic deciduous woodlands: Environmental controls and contribution to ecosystem evapotranspiration
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亚北极落叶林地的蒸腾：环境控制和对生态系统蒸散的贡献
DOI：
10.1002/eco.2190
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发表时间：
2020
期刊：
影响因子：
2.6
通讯作者：
Sabater A
中科院分区：
文献类型：
--
作者：
Sabater A
在亚北极地区，快速变暖正推动森林向苔原扩张，潜在的陆地气候反馈可能是由不同植物功能类型的蒸腾作用差异介导的。本文评估了亚北极落叶林地上层蒸腾的环境控制及其与生态系统蒸散的相关性。我们测量了芬诺斯坎迪亚北部两个地点的高山桦树冠层蒸腾和生态系统蒸散，这些地点的上层层密度为密集（Abisko）和稀疏（Kevo）。对于Kevo，我们还使用详细的土地覆盖图对室内测量的灌木和地衣的下层蒸散量进行了优化。亚日蒸发通量不受土壤湿度的影响，并受各站点间蒸汽压差和辐射的相似控制。在日时间尺度上，蒸发需求的增加导致上层蒸腾对生态系统蒸散的贡献比例增加。在整个生长季节，阿比斯库的上层蒸腾占生态系统蒸散量的33%，而凯沃仅占16%。后一样地林下叶面积指数高于林下，对生态系统蒸散的贡献大于林下林下。在阿比斯库，生长季蒸散量比降水高27%，这与夏季土壤水分逐渐枯竭相一致。结果表明，亚北极落叶林地的上层冠层蒸腾不是主要的蒸发通量。然而，考虑到观测到的蒸散发组分的环境敏感性，随着亚北极地区树木覆盖面积和蒸发需求的增加，落叶树对生态系统蒸散发的驱动作用可能会增加。
Potential land–climate feedbacks in subarctic regions, where rapid warming is driving forest expansion into the tundra, may be mediated by differences in transpiration of different plant functional types. Here, we assess the environmental controls of overstorey transpiration and its relevance for ecosystem evapotranspiration in subarctic deciduous woodlands. We measured overstorey transpiration of mountain birch canopies and ecosystem evapotranspiration in two locations in northern Fennoscandia, having dense (Abisko) and sparse (Kevo) overstories. For Kevo, we also upscale chamber‐measured understorey evapotranspiration from shrubs and lichen using a detailed land cover map. Subdaily evaporative fluxes were not affected by soil moisture and showed similar controls by vapour pressure deficit and radiation across sites. At the daily timescale, increases in evaporative demand led to proportionally higher contributions of overstorey transpiration to ecosystem evapotranspiration. For the entire growing season, the overstorey transpired 33% of ecosystem evapotranspiration in Abisko and only 16% in Kevo. At this latter site, the understorey had a higher leaf area index and contributed more to ecosystem evapotranspiration compared with the overstorey birch canopy. In Abisko, growing season evapotranspiration was 27% higher than precipitation, consistent with a gradual soil moisture depletion over the summer. Our results show that overstorey canopy transpiration in subarctic deciduous woodlands is not the dominant evaporative flux. However, given the observed environmental sensitivity of evapotranspiration components, the role of deciduous trees in driving ecosystem evapotranspiration may increase with the predicted increases in tree cover and evaporative demand across subarctic regions.
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影响因子：
9.7
作者：
Hartley, Iain P.;Hopkins, David W.;Wookey, Philip A.
通讯作者：
Wookey, Philip A.
未来气候变化：北极的建模和情景
DOI：
--
发表时间：
2005
期刊：
影响因子：
--
作者：
V. Kattsov;E. Källén;H. Cattle;J. Christensen;H. Drange;I. Hanssen‐Bauer;T. Jóhannesen;I. Karol;J. Räisänen;G. Svensson;Stanislav Vavulin
通讯作者：
Stanislav Vavulin
光合作用和生产力。
DOI：
--
发表时间：
2005
期刊：
影响因子：
--
作者：
C. Menzel;G. Waite
通讯作者：
G. Waite
使用自动化室系统测量北极蒸散量的昼夜循环
DOI：
--
发表时间：
2015
期刊：
影响因子：
--
作者：
L. Cohen;N. Raz‐Yaseef;J. Curtis;Jessica M. Young;T. Rahn;C. Wilson;S. Wullschleger;B. Newman
通讯作者：
B. Newman
影响因子：
11.6
作者：
Wang, Jonathan A.;Sulla-Menashe, Damien;Friedl, Mark A.
通讯作者：
Friedl, Mark A.