Intraspecific variation in seed dispersal of a Neotropical tree and its relationship to fruit and tree traits.
Intraspecific variation in seed dispersal of a Neotropical tree and its relationship to fruit and tree traits.
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DOI：
10.1002/ece3.1905
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发表时间：
2016-02
影响因子：
2.6
通讯作者：
Muller-Landau HC
中科院分区：
文献类型：
--
作者：
Augspurger CK;Franson SE;Cushman KC;Muller-Landau HC
风传播种子在母树周围的分布取决于一水硬铝石和树木的特征，以及风的条件和周围的植被。本研究以一种新热带树冠树--秀丽悬铃木为研究对象，探讨了一水硬铝石和树木性状的亲本变异在多大程度上解释了(1)一水硬铝石在静止空气中下降的速度，(2)散布在森林中40米高塔上的一水硬铝石的分布，以及(3)一水硬铝石在母树周围的自然分布。20名父母在静止空气中的几何平均下降率与几何平均翅膀载荷1/2高度相关(r=0.84)。然而，一水硬铝石特征和下降速率预示着离塔的扩散距离的变化较小，尽管下降速率−1与扩散距离一致相关。测量的种子阴影，特别是其分布边缘，在6个亲本(胸径范围62-181 cm)之间差异显著，最适合于6个独立的各向异性扩散核和调查的繁殖力。测量的下降速率和树木性状结合在一个机械的种子传播模型中，无法显著解释亲本之间在自然种子传播距离上的差异，可能是因为仅用六棵树检测影响的能力有限。苗木和幼树与亲本的平均距离大于种子分布；幼树高度集中在较远的距离。双亲在分布尾巴上的差异对补充至关重要，不能用这种样本量的一水硬铝石或树木特征来解释，更多的可能是由风型和与风条件有关的脱落时间决定的。风扩散的研究需要投入更大的实地努力，记录有助于远距离扩散的“罕见”扩散事件，跟踪其后果，并了解产生这些扩散事件的机制。
The distribution of wind‐dispersed seeds around a parent tree depends on diaspore and tree traits, as well as wind conditions and surrounding vegetation. This study of a neotropical canopy tree, Platypodium elegans, explored the extent to which parental variation in diaspore and tree traits explained (1) rate of diaspore descent in still air, (2) distributions of diaspores dispersed from a 40‐m tower in the forest, and (3) natural diaspore distributions around the parent tree. The geometric mean rate of descent in still air among 20 parents was highly correlated with geometric mean wing loading1/2 (r = 0.84). However, diaspore traits and rate of descent predicted less variation in dispersal distance from the tower, although descent rate−1 consistently correlated with dispersal distance. Measured seed shadows, particularly their distribution edges, differed significantly among six parents (DBH range 62–181 cm) and were best fit by six separate anisotropic dispersal kernels and surveyed fecundities. Measured rate of descent and tree traits, combined in a mechanistic seed dispersal model, did not significantly explain variation among parents in natural seed dispersal distances, perhaps due to the limited power to detect effects with only six trees. Seedling and sapling distributions were at a greater mean distance from the parents than seed distributions; saplings were heavily concentrated at far distances. Variation among parents in the distribution tails so critical for recruitment could not be explained by measured diaspore or tree traits with this sample size, and may be determined more by wind patterns and the timing of abscission in relation to wind conditions. Studies of wind dispersal need to devote greater field efforts at recording the “rare” dispersal events that contribute to far dispersal distances, following their consequences, and in understanding the mechanisms that generate them.