Seed and seedling demography of invasive and native trees of subtropical Pacific islands
Seed and seedling demography of invasive and native trees of subtropical Pacific islands
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DOI：
10.1111/j.1654-1103.2003.tb02123.x
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发表时间：
2003-02-01
影响因子：
2.8
通讯作者：
Kamo, K
中科院分区：
文献类型：
--
作者：
Yamashita, N;Tanaka, N;Kamo, K
Bischofia javanica是日本西太平洋小笠原群岛的一种入侵树种。该物种具有侵略性的生长，竞争性地取代了岛上天然森林中的本土树木。本研究的目的是检查种子和幼苗的因素，可能赋予优势，建立比肖菲亚比本土树木。在5年的时间内，我们比较了人口参数的早期生活史的Bischofia和杜英，原生冠层占主导地位，在积极入侵的森林。在种子传播前（27.9-32.9%）和传播后（41.3-100%），引进啮齿动物对杜英种子的捕食率明显高于B。javanica。大部分杜英种子在约100 ℃时丧失生活力。6个月后埋在森林土壤中，而一些Bischofia的种子保持活力超过2年。在第一个2年的幼苗存活率是高得多的Bischofia（16%）比杜英（1.3%）。Bischofia在阴凉处的高持久性，再加上它的快速适应高光水平，是一个不寻常的组合，因为在森林树种，一般有一个权衡幼苗在阴凉处的生存和树冠开放的反应。与本地冠层占主导地位相比，更大的种子寿命，较低的种子捕食引入啮齿动物，更长的结实期和封闭的树冠下形成幼苗银行的能力似乎有助于Bischofia小笠原群岛的入侵成功。
Bischofia javanica is an invasive tree of the Bonin Islands in the western Pacific, Japan. This species has aggressive growth, competitively replacing native trees in the natural forest of the islands. The aim of this study was to examine seed and seedling factors which might confer an advantage to the establishment of Bischofia over native trees. During a 5-yr period we compared the demographic parameters of early life history of Bischofia and Elaeocarpus photiniae-folius, a native canopy dominant, in actively invaded forests. Predation of Elaeocarpus seeds by introduced rodents was much higher before (27.9-32.9%) and after (41.3-100%) dispersal of seeds than that of B. javanica. Most Elaeocarpus seeds lost viability ca. 6 mo after burial in forest soil while some seeds of Bischofia remained viable for more than 2 yr. Seedling survival in the first 2 yr was much higher in Bischofia (16%) than in Elaeocarpus (1.3%). The high persistence of Bischofia in the shade, coupled to its rapid acclimation to high light levels, is an unusual combination because in forest tree species there is generally a trade-off between seedling survival in the shade and response to canopy opening. Compared with a native canopy dominant, greater seed longevity, lower seed predation by introduced rodents, longer fruiting periods and the ability to form seedling banks under closed canopy appear to have contributed to the invasive success of Bischofia on the Bonin Islands.