Distance and non-randomness of seed dispersal by the dwarf cassowary Casuarius bennetti
Distance and non-randomness of seed dispersal by the dwarf cassowary Casuarius bennetti
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侏儒食火鸡 Casuarius bennetti 种子传播的距离和非随机性
DOI：
10.1111/j.1600-0587.1995.tb00131.x
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发表时间：
1995
期刊：
影响因子：
5.9
通讯作者：
A. Mack
中科院分区：
文献类型：
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作者：
A. Mack
为了确定分散的种子的来源，我在倒下的米仔兰中插入了独特的标签。在矮食火鸡（Casuarius bennetti）吃掉含有种子的果实之前，三十自然分散，标记的种子重新定位在食火鸡粪便在400公顷的研究领域。种子传播距离的分布没有显着差异，从一个正常的分布，平均传播距离为388米，SD=196.8。分散的种子到最近的成熟同种树的平均距离为170米，SD=108.4 ;分散的种子通常降落在更接近其他同种比他们的父母。所有种子（包括许多未分散的种子）的估计分布呈尖峰形，在源树附近产生高密度（树干100 m内> 0.035种子m-2），并迅速逐渐减少（距树干100 m）;任何密度依赖效应仅在母树附近表现出来。食火鸡的运动模式和休息行为造成非随机传播的种子。种子优先移动到水平网站上坡从他们的源树沿着路线，没有跨越陡峭的地形。未分散的种子通常从源树落在下坡处。在没有食火鸡介导的扩散的情况下，这一种群的Aglaia可能会向下收缩成较小的、分散的种群。
To determine the sources of dispersed seeds I inserted unique tags in fallen Aglaia aff. flavida seeds before dwarf cassowaries (Casuarius bennetti) ate the fruits containing the seeds. Thirty naturally-dispersed, marked seeds were re-located in cassowary droppings in a 400 ha study area. The distribution of seed dispersal distances did not differ significantly from a normal distribution with a mean dispersal distance of 388 m, SD=196.8. Mean distance of dispersed seeds to nearest mature conspecific tree was 170 m, SD=108.4 ; dispersed seeds usually landed closer to other conspecifics than their parent. The estimated distribution of all seeds (including many undispersed seeds) was leptokurtic, creating high densities near source trees (> 0.035 seeds m -2 within 100 m of bole) that quickly tapered off ( 100 m from the bole) ; any density dependent effects are liable to be manifest only near parent trees. Cassowary movement patterns and resting behavior caused non-random dispersal of seeds. Seeds were preferentially moved to level sites uphill from their source trees along routes that did not cross steep terrain. Undispersed seeds generally landed downhill from source trees. This population of Aglaia would probably contract downhill into smaller, fragmented populations in the absence of cassowary-mediated dispersal.