The role of abscission in long-distance seed dispersal by the wind
The role of abscission in long-distance seed dispersal by the wind
复制标题
DOI：
10.1890/04-1430
复制
发表时间：
2005-11-01
期刊：
影响因子：
4.8
通讯作者：
Greene, DF
中科院分区：
文献类型：
--
作者：
Greene, DF
种子远距离传播在植物集合种群的持久性和对快速气候变化的响应中起着至关重要的作用。最近以蒲公英为例，研究了对流与剪切产生的上升气流在促进远距离扩散中的作用，表明（1）脱落的可能性与水平速度无关，因此（2）剪切引起的垂直湍流很低，因此默认情况下，大部分上升气流必须是由于对流，特别是在草原等开放栖息地。在本文中，我直接测试第一个假设，并通过建模练习间接测试第二个。采用较短的平均时间比以前使用的，它表明，在T。officinale由水平风速控制。事实上，它与风速的平方有关，如果阻力是动力，这是可以预料的。我还表明，这种增强的风速的偏置应充分增加剪切引起的湍流，使剪切对手对流作为一个来源的上升气流在开放的栖息地。总之，远距离扩散的风将不会成功地模拟，直到我们耦合的扩散和随后的扩散过程。
It has become clear that long-distance seed dispersal plays a crucial role in plant metapopulation persistence and response to rapid climate change. Recent studies of the role of convective vs. shear-generated updrafts in prompting long-distance dispersal using Taraxacum officinale as an example, suggest that (1) the probability of abscission is independent of horizontal speed and thus (2) shear-induced vertical turbulence is low, and so by default the bulk of updrafts must be due to convection, especially in open habitats such as grasslands. In this paper, I directly test the first hypothesis, and indirectly test the second via a modeling exercise. Employing shorter averaging times than used previously, it is shown that abscission in T. officinale is controlled by horizontal wind speed. Indeed, it is related to the square of the wind speed, as might be expected if drag is the motive force. I also show that this augmentation of wind speed by the abscission bias should sufficiently increase the shear-induced turbulence so that shear rivals convection as a source of updrafts in open habitats. In conclusion, long-distance dispersal by wind will not be successfully modeled until we couple the abscission and subsequent dispersal processes.