升高的二氧化碳增加了生产力和入侵物种在干旱的生态系统中的成功
S D Smith1, T E Huxman, S F Zitzer
1Department of Biological Sciences, University of Nevada, Las Vegas 89154-4004, USA. ssmith@ccmail.nevada.edu
Nature
|November 18, 2000
概括
大气中二氧化碳的升高显著提高了干旱生态系统的灌木生长在潮湿的年份,但不是干燥的. 这种变化有利于侵入性草,可能会改变沙漠生态系统.
科学领域:
- 生态生态学 生态生态学
- 气候变化生物学 气候变化生物学
- 植物生态学植物生态学
背景情况:
- 干旱的生态系统覆盖了地球20%的土地,对气候变化非常敏感.
- 大气中二氧化碳的增加是全球气候变化的关键驱动力.
- 莫哈维沙漠的生态系统面临着由于环境条件的变化而可能发生的转变.
研究的目的:
- 调查大气二氧化碳增加对莫哈韦沙漠生态系统中的植物生产的影响.
- 评估降雨变化如何影响沙漠植物对二氧化碳增加的反应.
- 为了确定二氧化碳增加对本地和入侵植物物种的差异性影响.
主要方法:
- 在一个完好无损的沙漠环境中,利用了自由空气二氧化碳丰富技术 (FACE).
- 监控主导多年生灌木的新芽生长.
- 量化地表产量和本地和入侵性一年生草的种子雨.
主要成果:
- 占主导地位的多年生灌木的新芽产量翻了一番,在降雨量高的一年中,二氧化碳增加了50%.
- 增加的二氧化碳在干旱年没有增加灌木生长.
- 与本地物种相比,侵入性一年草在高二氧化碳下显示出更大的产量增加和种子降雨.
结论:
- 升高的二氧化碳可以显著提高干旱地区的植物生产,但这种效应是由降雨调节的.
- 增加的二氧化碳有利于侵入性一年生草,而不是莫哈韦沙漠本地物种.
- 这种物种组成的转变可能会加速火灾周期,减少生物多样性,并改变北美沙漠的生态系统功能.
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