48,000年的气候和森林变化在一个生物多样性热点
Mark B Bush1, Miles R Silman, Dunia H Urrego
1Florida Institute of Technology, 150 West University Boulevard, Melbourne, FL 32901-6975, USA. mbush@fit.edu
Science (New York, N.Y.)
|February 7, 2004
概括
一个48,000年的古生态记录显示,新热带森林在冰河时代的冷却中持续存在. 物种交换标志着过渡到全新纪的条件,但与现代气候变化预测相比,其速度较慢.
科学领域:
- 古生态学 古生态学
- 气候科学 气候科学
- 新热带地区植物学
背景情况:
- 了解对气候变化的长期生态反应对于预测未来生态系统动态至关重要.
- 新热带地区拥有巨大的生物多样性,使其古生态历史对保护至关重要.
- 以前的记录提供了有限的分辨率,用于重建冰川-冰川间周期期间的过去森林动态.
研究的目的:
- 为了重建一个新热带低山林的古生态在过去的48,000年.
- 为了确定森林对冰河时代冷却和随后的变暖的反应.
- 将过去气候转型期间的生态变化速度与当前气候变化预测进行比较.
主要方法:
- 一个连续48,000年的古生态记录的分析.
- 花粉和宏观化石分析以确定植物物种和社区组成.
- 古气候重建以估计温度变化.
主要成果:
- 在整个48,000年的时间里,森林的存在始终保持不变.
- 大约5-9摄氏度的冷却发生在冰河时代.
- 一个长达3万年的组成稳定时期,在普世-全新世过渡期间,随之而来的是一个长达8000年的物种周转.
- 在过渡期间,社区的变化速度与稳定时期相当.
- 每千年升温率约为1摄氏度,比预计的21世纪升温速度要慢得多.
结论:
- 新热带森林通过显著的气候变化表现出性和持久性.
- 过去的气候转型,虽然有方向性,但并不一定会导致快速,不稳定的社区变化.
- 过去变暖的缓慢速度表明,目前的人为气候变化可能对生态系统稳定构成前所未有的挑战.
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