非洲大草原木质覆盖的决定因素
Mahesh Sankaran1, Niall P Hanan, Robert J Scholes
1Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, Colorado 80523, USA. mahesh@nrel.colostate.edu
Nature
|December 13, 2005
概括
非洲大草原的生态系统由水的可用性控制. 在干燥的草原中,水限制了树木的覆盖,而湿的草原则需要火灾等干扰来维持草和树的共存.
科学领域:
- 生态生态学 生态生态学
- 环境科学 环境科学
- 生物地理学是生物地理学.
背景情况:
- 萨凡纳,以共同占主导地位的树木和草为特征,是重要的全球生态系统.
- 森林覆盖是影响萨凡纳生态系统属性和动态的关键因素.
- 资源的可用性和干扰制度是沙漠结构的争论驱动因素.
研究的目的:
- 调查非洲沙原木质覆盖的主要驱动因素.
- 为了确定平均年降水 (MAP) 对草原结构的影响.
- 根据降水情况,区分稳定和不稳定的草原系统.
主要方法:
- 分析了来自非洲854个萨凡纳地区的数据.
- 统计检查MAP和最大木质覆盖之间的关系.
- 在不同降水门下对沙原动态进行比较.
主要成果:
- 在MAP小于650毫米的草原中,木质覆盖与MAP线性增加,表明水的限制.
- 干旱/半干旱的沙漠是"稳定的"系统,水限制了木质覆盖.
- 在MAP>650毫米的草原中,干扰是必要的,以防止木质树冠关闭,定义"不稳定"系统.
结论:
- 降水是构建非洲草原的关键因素,其值约为650毫米.
- 沙漠动态在干旱/半干旱和湿地区之间有很大差异.
- 未来降水变化可能会大大改变草原分布和生态动态.
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