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野火导致北美北极森林生态系统的光合作用增加
Jinhyuk E Kim1, Jonathan A Wang2, Yue Li3
1Department of Earth System Science, University of California, Irvine, California, USA.
Global change biology
|January 26, 2024
概括
北极森林的野火通过促进灌木和树叶树的生长来增加光合作用. 植物群落的这种转变增加了夏季二氧化碳的吸收,影响了北极.
科学领域:
- 生态生态学 生态生态学
- 遥感 遥感 遥感 遥感
- 生物地质化学生物地质化学
背景情况:
- 北极原和北极森林显示陆地新陈代谢增加,大气二氧化碳循环证明了这一点.
- 驱动这些变化的机制,特别是火灾引起的生态变化的作用,尚未完全理解.
- 火灾干扰可能会通过植物群体组成的变化改变净生态系统交换.
研究的目的:
- 调查火灾干扰如何影响北美西部北极地区的景观级光合作用模式.
- 用太阳诱导光 (SIF) 来量化火灾后植物继承对光合作用活动的影响.
- 确定火灾对SIF的长期趋势有所贡献的机制.
主要方法:
- 利用来自阿拉斯加和加拿大的大型火灾数据库来绘制野火周边地图.
- 使用Landsat衍生的土地覆盖时间序列来描述植物功能类型 (PFT).
- 使用来自轨道碳观测站-2 (OCO-2) 的太阳诱导光 (SIF) 数据作为光合作用的代理.
- 应用了空间对时间的方法来分析火灾后植物继承和光合作用活动的变化.
主要成果:
- 在6月和7月期间,在2-59岁的树群中,草本,稀疏植被,灌木和叶大叶森林PFT的中继增长增加了8-40%的SIF.
- 增加的年度燃烧转移支了年龄分布,有利于灌木和落叶森林,夏季初和中旬的SIF更高.
- 在北方平原生态区域,火灾促进了从常青针叶树长期转变为大叶落叶森林.
结论:
- 增加火灾频率有助于通过增强光合作用促进季节性二氧化碳交换的积极趋势.
- 火灾后的植被变化,特别是叶物种的增加,大大提高了夏季SIF.
- 这些发现突出了火在调节生态系统碳动态中的作用,独立于长期碳储存变化.
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