概括
加拿大落基山脉的木材线比今天高了3500年,然后普遍退缩. 这项研究详细介绍了贾斯珀国家公园过去8700年的林界波动.
科学领域:
- 古生态学 古生态学
- 四年纪地质学四年纪地质学
- 加拿大落基山脉古气候学 古气候学.
背景情况:
- 树木线的升高是气候变化的敏感指标.
- 了解过去的树林线动态对于预测未来的生态反应至关重要.
- 加拿大落基山脉的高海拔生态系统特别容易受到气候变化的影响.
研究的目的:
- 为了重建过去8700年的马利格尼山脉,贾斯珀国家公园的林界波动的历史.
- 为提供加拿大落基山脉林线动态的第一个详细的古生态记录.
- 为了将林界变化与区域气候变化相关联.
主要方法:
- 来自三个高海拔地区的化石花粉,化石日志和宏观化石的分析.
- 沉积物核心的年代测定采用已知的地质年代测定技术.
- 基于化石证据的过去林界位置的重建.
主要成果:
- 在8700到5200年前,木线比现在高得多.
- 森林线的高度发生了显著的波动,包括衰退时期 (67005900和87007000年前).
- 自5200年前以来,人们观察到林界衰退的一般趋势,达到500年前以来的最低水平.
结论:
- 加拿大落基山脉在全新纪期间经历了相当大的木材线变化.
- 过去的林界动态表明对气候变化的敏感性,有前进和后退的时期.
- 长期的经济衰退表明,过去几千年来,该地区的环境发生了重大变化.
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